Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
933–938
CAVITATION EROSION PROPERTIES OF A NICKEL-FREE
HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
RAZISKAVE ODPORNOSTI PROTI KAVITACIJSKI EROZIJI
Z DU[IKOM LEGIRANEGA Fe-Cr-Mn-N NERJAVNEGA JEKLA
Yanxin Qiao1, Xiang Cai1, Yipeng Chen1, Jie Cui2, Yanbing Tang3, Huabing Li4,
Zhouhua Jiang4
1Jiangsu University of Science and Technology, School of Materials Science and Technology, No.2 Mengxi Road, Zhenjiang, China
2Jiangsu University of Science and Technology, School of Naval Architecture and Ocean Engineering, No.2 Mengxi Road, Zhenjiang, China
3Jiangsu University of Science and Technology, Marine Equipment and Technology Institute, No.2 Mengxi Road, Zhenjiang, China
4Northeastern University, School of Metallurgy, No.2 Wenhua Road, Shenyang, China
yxqiao@just.edu.cn, cuijie2006@hotmail.com
Prejem rokopisa – received: 2017-03-22; sprejem za objavo – accepted for publication: 2017-05-12
doi:10.17222/mit.2017.034
The cavitation erosion behaviour of a nickel-free high-nitrogen stainless steel was investigated using 20-kHz vibratory
cavitation test equipment and analysed by scanning electron microscopy (SEM). The potentiodynamic polarization was
measured to clarify the role of corrosion on the cavitation erosion of tested steel. The results indicated that the cavitation erosion
damage in tested steel occurred initially at the grain boundary, twin boundary and interface between the precipitate and the
matrix. Cavitation shifted the corrosion potential to the cathodic direction in 0.5-M NaCl solution and leading to a
corrosion-current density almost two orders higher than that under static conditions. In the total cumulative mass loss under
cavitation erosion–corrosion conditions, the mechanical effect played a key role in a 0.5-M NaCl solution and the synergistic
effect induced by electrochemical and mechanical amounts to 14.78 % of the total mass loss.
Keywords: cavitation erosion, high-nitrogen stainless steel, corrosion, synergistic effect
Za raziskave odpornosti proti kavitacijski eroziji z du{ikom brez niklja, legiranega nerjavnega jekla, so uporabili preizkuse z 20
kHz vibracijsko kavitacijo in vrsti~no elektronsko mikroskopijo (SEM). Zato, da bi pojasnili vlogo kavitacijske korozije pri
preiskovanem jeklu, so izmerili potenciodinamsko polarizacijo. Rezultati so pokazali, da so se po{kodbe zaradi kavitacijske
erozije za~ele na mejah med zrni, mejah dvoj~kov in na mejah med izlo~ki in matrico. Preizkus v 0,5 M NaCl raztopini je
pokazal, da je kavitacija premaknila korozijski potencial v katodni smeri, ki vodi h skoraj za dve stopnji vi{ji korozijski gostoti
elektri~nega toka, kot je tisti v stati~nih pogojih preizku{anja. V celoti je za kumulativno izgubo mase v 0,5 M NaCl raztopini
pod kavitacijsko erozijsko-korozijskimi pogoji klju~no odgovoren mehanski u~inek. Celotna izguba mase je zna{ala 14,78 %
zaradi isto~asnega elektrokemijskega in mehansko induciranega delovanja.
Klju~ne besede: kavitacijska erozija, mo~no legirano du{ikovo nerjavno jeklo, korozija, vpliv sinergijskega delovanja
1 INTRODUCTION
Cavitation erosion (CE) is a common problem in
engineering parts in contact with a liquid. Plastic defor-
mation and erosion damage on the metal surfaces are
caused by the combination of shock loading and fatigue
as a result of the stress generated by the repeated growth
and collapse of cavities in the sheared liquid.1 High-
nitrogen stainless steel (HNSS) has attracted much
attention during the past several decades due to its
well-balanced combination of excellent mechanical
properties such as high strength and ductility, high
work-hardening ability, high stress-induced martensite
transformation and corrosion resistance.2,3 These
attractive properties make HNSS good candidates for use
in severe CE conditions.
HNSSs have been reported as suitable materials for
applications in which erosive damage caused by CE,
leading to a decrease in the large maintenance costs
characteristics of hydraulic systems.4,5 S. Z. Luo6 found
that the excellent CE resistance of CrMnN was related to
the good mechanical properties of the austenitic phase
and the consumption of CE energy by plastic deforma-
tion involving slip and twinning. W. Liu7 found that the
high CE resistance of CrMnN was mainly attributed to
their high work-hardening ability and favourable cavita-
tion crack propagation, i.e., parallel rather than perpen-
dicular to the specimen surface. H. Berns8 attributed the
better CE performance of HNSS to the effect of nitrogen
in lowering the stacking-fault energy (SFE), leading to
an increase in plasticity and work hardening. According
to W. T. Fu9 the high CE resistance of HNSS is related to
its good mechanical properties induced by changes in the
dislocation configurations, CE-induced mechanical
twinning or formation of stacking faults and CE-induced
phase transformation. P. Niederhofer10 found that the
superior CE resistance of HNSS is caused by the
strengthening effect of N and the low stacking-fault
energy leading to intense cold work hardening. W. T.
Fu11 studied the CE behaviour of CrMnN and showed
that CE could induce a new martensite structure and
delayed the progress of damage due to CE. D. J. Mill and
Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938 933
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
UDK 621.178.6:67.017:620.193.16 ISSN 1580-2949
Original scientific article/Izvirni znanstveni ~lanek MTAEC9, 51(6)933(2017)
R. D. Knutsen12 observed that the CE rate of CrMnN de-
creased with increasing amounts of cold working. They
stressed the importance of the increase in yield strength,
leading to a decrease of the plastic deformation inside
individual grains during the early CE stages, to a delay
of the onset of grain-boundaries extrusion and to a delay
of the fatigue damage nucleation and growth. J. F. San-
tos13 found that the superior CE resistance of nitride
304L stainless steel is attributed to the high elastic
energy. D. H. Mesa14 found that the high CE resistant of
HNSS is due to its high hardness and great resistance to
plastic deformation. The energy transferred by the shock
waves caused by imploding bubbles, during the earliest
stages of CE, is greatly consumed elastically without
leaving traces of plastic deformation on the surface.
In practice, many flow-handling components includ-
ing pumps and valves operate in corrosion environments,
where they are apparently subjected to the combined
action of CE and corrosion. Although the stainless steel
has a dense passive film, the corrosions still happen to
some components contacting liquids in fluid machinery
and become more obvious in the presence of CE, which
causes a more serious damage of components because of
the synergism of CE and corrosion.15,16 C. T. Kwok17
studied the CE behaviour of stainless steel in 3.5 % NaCl
and found that corrosion and corrosion/erosion
synergism play a negligible role.
Although a lot of publications on the CE perfor-
mance of HNSS have been published, a systematic inves-
tigation of the effect of corrosion on the CE characte-
ristics of HNSS was rarely reported in the literature. The
aim of this study was to investigate the relative
importance of CE, corrosion and the synergism between
them in the overall CE-corrosion damage of HNSS.
2 EXPERIMENTAL PART
2.1 Materials and specimen preparation
The HNSS used in this study was made by the
dissolution of the raw materials in a high-vacuum
furnace, followed by forging, hot rolling, cold rolling
and then air cooling to room temperature. The HNSS
was in the form of a round bar with a diameter of 20
mm. The chemical composition of HNSS is listed in
Table 1.
Table 1: Chemical composition of HNSS used in this study (w/%)
C Si Mn P S Cr Mo N Fe
0.048 0.24 15.96 0.004 0.017 18.44 2.23 0.66 Bal.
The shape and dimension of the specimen used has
been given in a previous study.15 Test surfaces were
gradually ground down to 1000 grit and polished using
1.5-μm alumina powder before the CE test to observe the
response of different phases to CE later. Specimens were
degreased by immersion in acetone in an ultrasonic bath
and were rinsed with distilled water, then dried and
stored in desiccators. The specimens used for the
microstructure observation was electrolytically etched in
10 % ethanedioic acid reagent at 12 V for 90 s.
2.2 Test method
CE was produced by a magnetostrictive-induced
cavitation facility (Sonicator XL 2020) resonating at 20
kHz with a peak-to-peak amplitude of 60 μm. This test
followed ASTM Standard G32-92. The cavitation tests
were performed in distilled water and 0.5-M NaCl.
Reagent grade NaCl and distilled water were used. The
temperature of the tested solution was maintained in the
range 20±1 °C.
For the CE test, the specimen was screwed into the
horn and immersed into the test medium to a depth of 15
mm. After each test period, the specimen was degreased,
rinsed, dried, and weighed using an analytical balance
(Sartorius BT25S) with an accuracy of 0.1 mg. To ensure
the reproducibility of the results, every test was repeated
three times. The potentiodynamic polarization tests were
performed with a CS350 workstation (Corrtest Instru-
ment, China). Using a platinum plate as the counter-
electrode and a saturated calomel electrode (SCE) as the
reference electrode, a classic three-electrode system was
used in the electrochemical measurements. Potentiodyn-
amic polarization was started after CE for 15 min and
swept from –400 mV relative to corrosion potential at a
fixed rate of 1 mV/s until a current density of
10 mA/cm–2 was reached.
In order to investigate the mechanism of material
removal during CE, specimens were examined after fixed
cavitation intervals. The microstructures of HNSS and
the eroded surfaces of the samples examined using XL20
scanning electron microscopy (SEM). The crystal struc-
tures of the HNSSs were studied by XRD (Philips
PW3710), using Cu-K radiation generated at 40 kV and
35 mA.
3 RESULTS AND DISCUSSION
3.1 Material characterization
Figure 1 shows the SEM morphology of the
as-received HNSS. It is clear that HNSS consisted of a
typical  (austenitic) phase matrix with twin boundaries
and precipitated Cr2N.18,19 The EDS of HNSS and
precipitated particles were shown in Table 2. The XRD
analysis in Figure 2 shows that HNSS was in a single 
phase, while the dispersed precipitated Cr2N cannot be
detected.
Table 2: EDS of as-received HNSS and Cr2N, in mass fractions (w/%)
Area Fe Cr Mn Mo Si N
1 5.01 78.83 4.03 0.72 0.58 10.83
2 61.32 18.33 17.37 2.98 - -
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
934 Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
3.2 Mass loss
Figure 3 presents the mass-loss curve versus CE
time, which indicates that the CE resistance can be
influenced by the corrosivity of the tested solution. After
CE for 8 h, the mass loss of HNSS in 0.5-M NaCl was
1.17 times that in distilled water. In distilled water, the
mass loss rate curves of HNSS could be divided into two
stages. The mass loss rate was characterized by a very
low value and kept almost constant within 4 h, and it
could be regarded as an incubation period. After a CE
time of 4 h the mass-loss rate increased quickly and
linearly with the CE time. Generally, it is believed that
the duration of incubation time depends on how long
microcracks need to initiate by collapse. Material with
longer incubation periods is considered to have a
superior CE resistance. In contrast, the mass loss rate
was characterized by a high value in the 0.5-M NaCl
solution. After CE for 2 h, the mass-loss rate reached a
constant stage. This indicated that the CE resistance of
HNSS in distilled water was better than that in a NaCl
solution. The initiation and propagation of microcracks
can be facilitated by corrosion media. This could be
further confirmed by SEM observation in the later
stages.
3.3 Electrochemical behaviour
In order to investigate the effect of corrosion on CE
behaviour of HNSS, polarization curves were tested
under static and CE conditions in 0.5-M NaCl and shown
in Figure 4. It can be seen that the corrosion behaviour
of the HNSS under both static conditions and CE con-
ditions exhibited similar polarization behaviour. The
anodic current density gradually increased by increasing
the electrode potential under both static and CE condi-
tions. The corrosion potential under static and CE condi-
tion was –212.05 mVSCE and –506.96 mVSCE, respec-
tively. The corrosion current density (icorr) of HNSS
under static and CE conditions is 1.39 μA/cm2 and
133.97 μA/cm2, respectively. The results obtained indi-
cating that cavitation shifted the corrosion potential to a
negative direction and increased the anodic current
densities by two orders of magnitude. The corrosion of
HNSS in the static condition was controlled by the
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938 935
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 2: XRD of as-received HNSS
Figure 1: SEM micrograph of as-received HNSS
Figure 4: Potentiodynamic polarization curves for HNSS in 0.5 M
NaCl and 0.5 MHCl solution under static and CE condition
Figure 3: Mass-loss rate for HNSS in tested solutions under CE
condition
R. D. Knutsen12 observed that the CE rate of CrMnN de-
creased with increasing amounts of cold working. They
stressed the importance of the increase in yield strength,
leading to a decrease of the plastic deformation inside
individual grains during the early CE stages, to a delay
of the onset of grain-boundaries extrusion and to a delay
of the fatigue damage nucleation and growth. J. F. San-
tos13 found that the superior CE resistance of nitride
304L stainless steel is attributed to the high elastic
energy. D. H. Mesa14 found that the high CE resistant of
HNSS is due to its high hardness and great resistance to
plastic deformation. The energy transferred by the shock
waves caused by imploding bubbles, during the earliest
stages of CE, is greatly consumed elastically without
leaving traces of plastic deformation on the surface.
In practice, many flow-handling components includ-
ing pumps and valves operate in corrosion environments,
where they are apparently subjected to the combined
action of CE and corrosion. Although the stainless steel
has a dense passive film, the corrosions still happen to
some components contacting liquids in fluid machinery
and become more obvious in the presence of CE, which
causes a more serious damage of components because of
the synergism of CE and corrosion.15,16 C. T. Kwok17
studied the CE behaviour of stainless steel in 3.5 % NaCl
and found that corrosion and corrosion/erosion
synergism play a negligible role.
Although a lot of publications on the CE perfor-
mance of HNSS have been published, a systematic inves-
tigation of the effect of corrosion on the CE characte-
ristics of HNSS was rarely reported in the literature. The
aim of this study was to investigate the relative
importance of CE, corrosion and the synergism between
them in the overall CE-corrosion damage of HNSS.
2 EXPERIMENTAL PART
2.1 Materials and specimen preparation
The HNSS used in this study was made by the
dissolution of the raw materials in a high-vacuum
furnace, followed by forging, hot rolling, cold rolling
and then air cooling to room temperature. The HNSS
was in the form of a round bar with a diameter of 20
mm. The chemical composition of HNSS is listed in
Table 1.
Table 1: Chemical composition of HNSS used in this study (w/%)
C Si Mn P S Cr Mo N Fe
0.048 0.24 15.96 0.004 0.017 18.44 2.23 0.66 Bal.
The shape and dimension of the specimen used has
been given in a previous study.15 Test surfaces were
gradually ground down to 1000 grit and polished using
1.5-μm alumina powder before the CE test to observe the
response of different phases to CE later. Specimens were
degreased by immersion in acetone in an ultrasonic bath
and were rinsed with distilled water, then dried and
stored in desiccators. The specimens used for the
microstructure observation was electrolytically etched in
10 % ethanedioic acid reagent at 12 V for 90 s.
2.2 Test method
CE was produced by a magnetostrictive-induced
cavitation facility (Sonicator XL 2020) resonating at 20
kHz with a peak-to-peak amplitude of 60 μm. This test
followed ASTM Standard G32-92. The cavitation tests
were performed in distilled water and 0.5-M NaCl.
Reagent grade NaCl and distilled water were used. The
temperature of the tested solution was maintained in the
range 20±1 °C.
For the CE test, the specimen was screwed into the
horn and immersed into the test medium to a depth of 15
mm. After each test period, the specimen was degreased,
rinsed, dried, and weighed using an analytical balance
(Sartorius BT25S) with an accuracy of 0.1 mg. To ensure
the reproducibility of the results, every test was repeated
three times. The potentiodynamic polarization tests were
performed with a CS350 workstation (Corrtest Instru-
ment, China). Using a platinum plate as the counter-
electrode and a saturated calomel electrode (SCE) as the
reference electrode, a classic three-electrode system was
used in the electrochemical measurements. Potentiodyn-
amic polarization was started after CE for 15 min and
swept from –400 mV relative to corrosion potential at a
fixed rate of 1 mV/s until a current density of
10 mA/cm–2 was reached.
In order to investigate the mechanism of material
removal during CE, specimens were examined after fixed
cavitation intervals. The microstructures of HNSS and
the eroded surfaces of the samples examined using XL20
scanning electron microscopy (SEM). The crystal struc-
tures of the HNSSs were studied by XRD (Philips
PW3710), using Cu-K radiation generated at 40 kV and
35 mA.
3 RESULTS AND DISCUSSION
3.1 Material characterization
Figure 1 shows the SEM morphology of the
as-received HNSS. It is clear that HNSS consisted of a
typical  (austenitic) phase matrix with twin boundaries
and precipitated Cr2N.18,19 The EDS of HNSS and
precipitated particles were shown in Table 2. The XRD
analysis in Figure 2 shows that HNSS was in a single 
phase, while the dispersed precipitated Cr2N cannot be
detected.
Table 2: EDS of as-received HNSS and Cr2N, in mass fractions (w/%)
Area Fe Cr Mn Mo Si N
1 5.01 78.83 4.03 0.72 0.58 10.83
2 61.32 18.33 17.37 2.98 - -
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
934 Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
3.2 Mass loss
Figure 3 presents the mass-loss curve versus CE
time, which indicates that the CE resistance can be
influenced by the corrosivity of the tested solution. After
CE for 8 h, the mass loss of HNSS in 0.5-M NaCl was
1.17 times that in distilled water. In distilled water, the
mass loss rate curves of HNSS could be divided into two
stages. The mass loss rate was characterized by a very
low value and kept almost constant within 4 h, and it
could be regarded as an incubation period. After a CE
time of 4 h the mass-loss rate increased quickly and
linearly with the CE time. Generally, it is believed that
the duration of incubation time depends on how long
microcracks need to initiate by collapse. Material with
longer incubation periods is considered to have a
superior CE resistance. In contrast, the mass loss rate
was characterized by a high value in the 0.5-M NaCl
solution. After CE for 2 h, the mass-loss rate reached a
constant stage. This indicated that the CE resistance of
HNSS in distilled water was better than that in a NaCl
solution. The initiation and propagation of microcracks
can be facilitated by corrosion media. This could be
further confirmed by SEM observation in the later
stages.
3.3 Electrochemical behaviour
In order to investigate the effect of corrosion on CE
behaviour of HNSS, polarization curves were tested
under static and CE conditions in 0.5-M NaCl and shown
in Figure 4. It can be seen that the corrosion behaviour
of the HNSS under both static conditions and CE con-
ditions exhibited similar polarization behaviour. The
anodic current density gradually increased by increasing
the electrode potential under both static and CE condi-
tions. The corrosion potential under static and CE condi-
tion was –212.05 mVSCE and –506.96 mVSCE, respec-
tively. The corrosion current density (icorr) of HNSS
under static and CE conditions is 1.39 μA/cm2 and
133.97 μA/cm2, respectively. The results obtained indi-
cating that cavitation shifted the corrosion potential to a
negative direction and increased the anodic current
densities by two orders of magnitude. The corrosion of
HNSS in the static condition was controlled by the
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938 935
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 2: XRD of as-received HNSS
Figure 1: SEM micrograph of as-received HNSS
Figure 4: Potentiodynamic polarization curves for HNSS in 0.5 M
NaCl and 0.5 MHCl solution under static and CE condition
Figure 3: Mass-loss rate for HNSS in tested solutions under CE
condition
dissolution of the passive film and repassivation of the
metal. The passive film on the surface of HNSS can be
damaged locally by a random collapse of bubbles and
results in the dissolution of material and will cause the
total anodic current density to increase a lot. The
influence of CE on the corrosion potential is attributed to
the reason that a relatively stronger influence on anodic
reaction than that of cathodic reaction.20,21 It is well
known that chloride ions will induce pitting corrosion in
stainless steels in static conditions. Under CE conditions,
stirring of the electrolyte and film destruction occur
simultaneously,22 both upsetting the local environment
for pit growth. Thus the effect of cavitation remains
mechanical, even in the presence of chloride ions.17
3.4 Evolution of CE damage of HNSS
The microstructure change of HNSS in each period
was observed continuously. Figure 5 shows the surface
micrographs of HNSS after CE for different time inter-
vals in distilled water. Figure 5a shows the appearance
of the surface after a CE time of 1 h. The eroded surface
was characterized by the formation of surface undula-
tions, labelled A, and cavities, labelled B, caused by
material removal appeared along grain boundaries can be
clearly seen. This provided evidence that CE damage
was firstly initiated at grain boundaries and is consistent
with the results reported by S. Z. Luo,6 who reported that
CE damage arising from material extrusions at grain
boundaries in polycrystalline materials. Slip lines,
labelled C, and deformed twins, labelled D, can also be
seen clearly inside austenite grains. The surface exhi-
bited plastic deformation in the form of surface undula-
tions as well as the appearance of grain boundaries, slip
bands, and twin boundaries in incubation periods.10,12
Figure 5b shows the appearance of the surface after a
CE time of 3 h. It can be seen that material removal was
preferentially at the grain boundaries and cavities, then
growth towards the inner region of the grains. The mass
removal inside the grains starts at slip lines and
deformed twins. This is consistent with the results
reported by Mills and Knutsen12. It could also be seen
that some grains are much more deformed than others,
indicating significant plasticity anisotropy at the
mesoscale, which can be addressed to different values of
the resolved shear stress inside each grain.15 The
damaged surface after CE for 5h is shown in Figure 5c,
in which craters about 2-5 μm in diameter and cracks can
be observed. The craters were created due to the removal
of material by a combined effect of microfatigue and
microcrack formation. After CE for 8 h, the propagation
and connection of the microcracks by fatigue at
continuous impact of bubble collapse, give to the larger
craters and wide cracks, as shown in Figure 5d. This is
consistent with the mass-loss rate presented in Figure 3
that larger bulk material was lost in this period.
The morphologies of the eroded surfaces in 0.5-M
NaCl were slightly different to that in distilled water for
the same time intervals. Figure 6 shows surface micro-
graphs of HNSS after CE for different time intervals in
0.5-M NaCl. Figure 6a indicates that plastic deformation
and surface undulations are more serious than that in
distilled water, more slip lines formed inside grains and
discontinuous at grain boundaries. The active dissolution
of HNSS can be clearly seen on the surface, especially at
site of slip line intersections. After CE for 3 h, the
cavitated surface was very rough and only a little
original surface be preserved, deep gaps and cracks due
to the material removal at the grain boundaries can be
clearly seen, as shown in Figure 6b. These results
suggested that mass loss of HNSS in 0.5-M NaCl
solution was significantly enhanced and consistent with
the results that mass loss is almost constant in 0.5-M
NaCl solution after the initial increase. Figure 6c and 6d
shows the surface of HNSS after CE for 5 h and 8 h. The
eroded surface of the HNSS was found to be similar to
that in distilled water in that they are all characterized by
the formation of craters and fatigue cracks on the sample
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
936 Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 6: SEM images of HNSS after CE for: a)1 h, b)3 h, c)5 h and
d) 8 h in 0.5 M NaCl solution
Figure 5: SEM images of HNSS after CE for : a) 1 h, b) 3 h , c) 5 h
and d) 8 h in distilled water: A- surface undulations, B- cavities, C-
slip lines, D-deformed twins
surface. The size of cater is smaller than that in the
distilled water. This indicates corrosion played an
important role in that it can promote the crack initiation
and propagation of the cracks.
The overall CE rate is constituted by an erosion rate,
a corrosion rate and a synergistic effect of erosion and
corrosion.15–17,23–25 The synergistic effect of electrochemi-
cal and mechanical factor produced far more damage
than if each acted separately in a large number of sys-
tems. The total mass loss is composed of erosion mass
loss, corrosion mass loss and synergistic effect of erosion
and corrosion. In corrosive media the total material loss
can be expressed by:20
WT + WE + WC + WS= WC + WE + WCIE + WEIC (1)
where WT is the total CE material loss, WE is the com-
ponent of pure erosion part, WC is the fraction of pure
corrosion under static condition, WS is volume loss rate
of synergism, WEIC is the fraction of erosion induced
corrosion, WCIE is the fraction of erosion induced corro-
sion.
Table 3: Mass loss induced by pure corrosion (WC), pure erosion
(WE), erosion-induced corrosion (WEIC) and corrosion induced erosion
(WCIE) and ratios of each factor for HNSS in 0.5 M NaCl
Mass loss (mg) Damage fraction (%
WT WC WE WEIC WCIE fC fE fEIC fCIE
12.45 0.01 10.60 1.10 0.74 0.08 85.14 8.83 5.95
Note: fC ratio of pure corrosion, fE ratio of pure erosion, fEIC ratio of
erosion-induced corrosion, fCIE ratio of corrosion-induced erosion,
WT mass loss induced by CE
In present work, WT was the cumulative mass loss
under CE conditions for 8 h in 0.5-M NaCl. WE were the
cumulative mass loss under CE condition for 8 h in
distilled water. WC was calculated from the icorr in the
polarization curve under static conditions according to
Faraday’s law. WEIC was calculated from the icorr in the
polarization curve under CE and WCIE could be obtained
from Equation (1). Table 3 lists the parameters described
above. It indicated that the contribution of the synergistic
component (WEIC and WCIE) to WT was 14.78 %, which
meant that the mechanical effect was the main factor for
the CE–corrosion behaviour of HNSS, but at the same
time the contribution of corrosion cannot be neglected.
4 CONCLUSION
The cumulative mass loss of the HNSS in 0.5-M
NaCl was about 1.17 times that in distilled water. CE
shifted the corrosion potential of HNSS to cathodic
direction in 0.5-M NaCl. The anodic reactions under
cavitation conditions were two orders of magnitude
faster than that in quiescent conditions. Cavitation
erosion damage began at the grain, twin boundaries and
interfaces between Cr2N. In the total cumulative mass
loss under CE corrosion conditions, the mechanical
effect played a key role for HNSS and the synergistic
component was 14.78 % in 0.5-M NaCl. The propaga-
tion and connection of cracks can be facilitated by the
corrosivity of the tested media.
Acknowledgements
We wish to express our gratitude to the financial
support of the National Natural Science Foundation of
China (Nos.51401092, 51409129, 51131008, 51434004,
U1435205 and 51304041) and Natural Science Foun-
dation of Jiangsu Province (BK20140504) for the
finance support of this research.
5 REFERENCES
1 A. Karimi, J. L. Martin, Cavitation erosion of materials, Int. Mater.
Rev., 31 (2013), 1–26, doi:10.1179/imtr.1986.31.1.1
2 M. Moallemi, A. Zarei-Hanzaki, H. S. Baghbadorani. Evolution of
microstructure and mechanical properties in a cold deformed
nitrogen bearing TRIP-assisted duplex stainless steel after reversion
annealing. Mater. Sci. Eng. A, 683 (2016), 83–89, doi:10.1016/
j.msea.2016.10.105
3 F. Y. Dong, P. Zhang, J. C. Pang, Y. B. Ren, K. Yang, Z. F. Zhang,
Strength, damage and fracture behaviors of high-nitrogen austenitic
stainless steel processed by high-pressure torsion, Scripta Mater., 96
(2015), 5–8, doi:10.1016/j.scriptamat.2014.09.016
4 Y. G. Zheng, S. Z. Luo, W. Ke, Cavitation erosion–corrosion beha-
viour of CrMnB stainless overlay and 0Cr13Ni5Mo stainless steel in
0.5M NaCl and 0.5M HCl solutions, Tribol. Int., 41 (2008),
1181–1189, doi:10.1016/j.triboint.2008.02.011
5 H. Hänninen, J. Romu, R. Ilola, J. Tervo, A. Laitinen, Effects of
processing and manufacturing of high nitrogen-containing stainless
steels on their mechanical, corrosion and wear properties, J. Mater.
Process. Technol., 117 (2001), 424–430, doi:10.1016/S0924-
0136(01)00804-4
6 S. Z. Luo, Y. G. Zheng, W. Liu, H. M Jing, Z. M Yao, W. Ke,
Cavitation erosion behavior of CrMnN duplex stainless steel in
distilled water and 3% NaCl solution, J. Mater. Sci. Technol., 19
(2003), 346–350, doi:10.3321/j.issn:1005-0302.2003.04.016
7 W. Liu, Y. G. Zheng, C. S. Liu, Z. M. Yao, W. Ke, Cavitation erosion
behavior of Cr-Mn-N stainless steels in comparison with
0Cr13Ni5Mo stainless steel, Wear, 254 (2003), 713–722,
doi:10.1016/S0043-1648(03)00128-5
8 H. Berns, S. Siebert, High nitrogen austenitic cases in stainless
steels. ISIJ Inter., 36 (1996), 927–931, doi:10.2355/isijinternational.
36.927
9 W. T. Fu, Y. Z. Zheng, X. K. He, Resistance of a high nitrogen
austenitic steel to cavitation erosion, Wear, 249 (2001), 788–791,
doi:10.1016/S0043-1648(01)00811-0
10 P. Niederhofer, L. Richrath, S. Huth, W. Theisen, Influence of con-
ventional and powder-metallurgical manufacturing on the cavitation
erosion and corrosion of high interstitial CrMnN austenitic stainless
steels, Wear, 360–361 (2016), 67–76, doi:10.1016/j.wear.2016.
04.017
11 W. T. Fu, Y. B. Yang, T. F. Jing, Y. Z. Zheng, M. Yao, The resistance
to cavitation erosion of CrMnN stainless steels, J. Mater. Eng.
Perform., 7 (1998), 801–804, doi:10.1361/105994998770347396
12 D. J. Mills, R.D. Knutsen, An investigation of the tribological
behaviour of a high-nitrogen Cr-Mn austenitic stainless steel, Wear,
215 (1998), 83–90, doi:10.1016/S0043-1648(97)00273-1
13 J. F. Santos, C. M. Garzón, A. P. Tschiptschin, Improvement of the
cavitation erosion resistance of an AISI 304L austenitic stainless
steel by high temperature gas nitriding, Mater. Sci. Eng. A, 382
(2004), 378–386, doi:10.1016/j.msea.2004.05.003
14 D. H. Mesa, C. M. Garzón, A. P. Tschiptschin, Influence of cold-
work on the cavitation erosion resistance and on the damage
mechanisms in high-nitrogen austenitic stainless steels, Wear, 271
(2011), 1372–1377, doi:10.1016/j.wear.2011.01. 063
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938 937
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
dissolution of the passive film and repassivation of the
metal. The passive film on the surface of HNSS can be
damaged locally by a random collapse of bubbles and
results in the dissolution of material and will cause the
total anodic current density to increase a lot. The
influence of CE on the corrosion potential is attributed to
the reason that a relatively stronger influence on anodic
reaction than that of cathodic reaction.20,21 It is well
known that chloride ions will induce pitting corrosion in
stainless steels in static conditions. Under CE conditions,
stirring of the electrolyte and film destruction occur
simultaneously,22 both upsetting the local environment
for pit growth. Thus the effect of cavitation remains
mechanical, even in the presence of chloride ions.17
3.4 Evolution of CE damage of HNSS
The microstructure change of HNSS in each period
was observed continuously. Figure 5 shows the surface
micrographs of HNSS after CE for different time inter-
vals in distilled water. Figure 5a shows the appearance
of the surface after a CE time of 1 h. The eroded surface
was characterized by the formation of surface undula-
tions, labelled A, and cavities, labelled B, caused by
material removal appeared along grain boundaries can be
clearly seen. This provided evidence that CE damage
was firstly initiated at grain boundaries and is consistent
with the results reported by S. Z. Luo,6 who reported that
CE damage arising from material extrusions at grain
boundaries in polycrystalline materials. Slip lines,
labelled C, and deformed twins, labelled D, can also be
seen clearly inside austenite grains. The surface exhi-
bited plastic deformation in the form of surface undula-
tions as well as the appearance of grain boundaries, slip
bands, and twin boundaries in incubation periods.10,12
Figure 5b shows the appearance of the surface after a
CE time of 3 h. It can be seen that material removal was
preferentially at the grain boundaries and cavities, then
growth towards the inner region of the grains. The mass
removal inside the grains starts at slip lines and
deformed twins. This is consistent with the results
reported by Mills and Knutsen12. It could also be seen
that some grains are much more deformed than others,
indicating significant plasticity anisotropy at the
mesoscale, which can be addressed to different values of
the resolved shear stress inside each grain.15 The
damaged surface after CE for 5h is shown in Figure 5c,
in which craters about 2-5 μm in diameter and cracks can
be observed. The craters were created due to the removal
of material by a combined effect of microfatigue and
microcrack formation. After CE for 8 h, the propagation
and connection of the microcracks by fatigue at
continuous impact of bubble collapse, give to the larger
craters and wide cracks, as shown in Figure 5d. This is
consistent with the mass-loss rate presented in Figure 3
that larger bulk material was lost in this period.
The morphologies of the eroded surfaces in 0.5-M
NaCl were slightly different to that in distilled water for
the same time intervals. Figure 6 shows surface micro-
graphs of HNSS after CE for different time intervals in
0.5-M NaCl. Figure 6a indicates that plastic deformation
and surface undulations are more serious than that in
distilled water, more slip lines formed inside grains and
discontinuous at grain boundaries. The active dissolution
of HNSS can be clearly seen on the surface, especially at
site of slip line intersections. After CE for 3 h, the
cavitated surface was very rough and only a little
original surface be preserved, deep gaps and cracks due
to the material removal at the grain boundaries can be
clearly seen, as shown in Figure 6b. These results
suggested that mass loss of HNSS in 0.5-M NaCl
solution was significantly enhanced and consistent with
the results that mass loss is almost constant in 0.5-M
NaCl solution after the initial increase. Figure 6c and 6d
shows the surface of HNSS after CE for 5 h and 8 h. The
eroded surface of the HNSS was found to be similar to
that in distilled water in that they are all characterized by
the formation of craters and fatigue cracks on the sample
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
936 Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
Figure 6: SEM images of HNSS after CE for: a)1 h, b)3 h, c)5 h and
d) 8 h in 0.5 M NaCl solution
Figure 5: SEM images of HNSS after CE for : a) 1 h, b) 3 h , c) 5 h
and d) 8 h in distilled water: A- surface undulations, B- cavities, C-
slip lines, D-deformed twins
surface. The size of cater is smaller than that in the
distilled water. This indicates corrosion played an
important role in that it can promote the crack initiation
and propagation of the cracks.
The overall CE rate is constituted by an erosion rate,
a corrosion rate and a synergistic effect of erosion and
corrosion.15–17,23–25 The synergistic effect of electrochemi-
cal and mechanical factor produced far more damage
than if each acted separately in a large number of sys-
tems. The total mass loss is composed of erosion mass
loss, corrosion mass loss and synergistic effect of erosion
and corrosion. In corrosive media the total material loss
can be expressed by:20
WT + WE + WC + WS= WC + WE + WCIE + WEIC (1)
where WT is the total CE material loss, WE is the com-
ponent of pure erosion part, WC is the fraction of pure
corrosion under static condition, WS is volume loss rate
of synergism, WEIC is the fraction of erosion induced
corrosion, WCIE is the fraction of erosion induced corro-
sion.
Table 3: Mass loss induced by pure corrosion (WC), pure erosion
(WE), erosion-induced corrosion (WEIC) and corrosion induced erosion
(WCIE) and ratios of each factor for HNSS in 0.5 M NaCl
Mass loss (mg) Damage fraction (%
WT WC WE WEIC WCIE fC fE fEIC fCIE
12.45 0.01 10.60 1.10 0.74 0.08 85.14 8.83 5.95
Note: fC ratio of pure corrosion, fE ratio of pure erosion, fEIC ratio of
erosion-induced corrosion, fCIE ratio of corrosion-induced erosion,
WT mass loss induced by CE
In present work, WT was the cumulative mass loss
under CE conditions for 8 h in 0.5-M NaCl. WE were the
cumulative mass loss under CE condition for 8 h in
distilled water. WC was calculated from the icorr in the
polarization curve under static conditions according to
Faraday’s law. WEIC was calculated from the icorr in the
polarization curve under CE and WCIE could be obtained
from Equation (1). Table 3 lists the parameters described
above. It indicated that the contribution of the synergistic
component (WEIC and WCIE) to WT was 14.78 %, which
meant that the mechanical effect was the main factor for
the CE–corrosion behaviour of HNSS, but at the same
time the contribution of corrosion cannot be neglected.
4 CONCLUSION
The cumulative mass loss of the HNSS in 0.5-M
NaCl was about 1.17 times that in distilled water. CE
shifted the corrosion potential of HNSS to cathodic
direction in 0.5-M NaCl. The anodic reactions under
cavitation conditions were two orders of magnitude
faster than that in quiescent conditions. Cavitation
erosion damage began at the grain, twin boundaries and
interfaces between Cr2N. In the total cumulative mass
loss under CE corrosion conditions, the mechanical
effect played a key role for HNSS and the synergistic
component was 14.78 % in 0.5-M NaCl. The propaga-
tion and connection of cracks can be facilitated by the
corrosivity of the tested media.
Acknowledgements
We wish to express our gratitude to the financial
support of the National Natural Science Foundation of
China (Nos.51401092, 51409129, 51131008, 51434004,
U1435205 and 51304041) and Natural Science Foun-
dation of Jiangsu Province (BK20140504) for the
finance support of this research.
5 REFERENCES
1 A. Karimi, J. L. Martin, Cavitation erosion of materials, Int. Mater.
Rev., 31 (2013), 1–26, doi:10.1179/imtr.1986.31.1.1
2 M. Moallemi, A. Zarei-Hanzaki, H. S. Baghbadorani. Evolution of
microstructure and mechanical properties in a cold deformed
nitrogen bearing TRIP-assisted duplex stainless steel after reversion
annealing. Mater. Sci. Eng. A, 683 (2016), 83–89, doi:10.1016/
j.msea.2016.10.105
3 F. Y. Dong, P. Zhang, J. C. Pang, Y. B. Ren, K. Yang, Z. F. Zhang,
Strength, damage and fracture behaviors of high-nitrogen austenitic
stainless steel processed by high-pressure torsion, Scripta Mater., 96
(2015), 5–8, doi:10.1016/j.scriptamat.2014.09.016
4 Y. G. Zheng, S. Z. Luo, W. Ke, Cavitation erosion–corrosion beha-
viour of CrMnB stainless overlay and 0Cr13Ni5Mo stainless steel in
0.5M NaCl and 0.5M HCl solutions, Tribol. Int., 41 (2008),
1181–1189, doi:10.1016/j.triboint.2008.02.011
5 H. Hänninen, J. Romu, R. Ilola, J. Tervo, A. Laitinen, Effects of
processing and manufacturing of high nitrogen-containing stainless
steels on their mechanical, corrosion and wear properties, J. Mater.
Process. Technol., 117 (2001), 424–430, doi:10.1016/S0924-
0136(01)00804-4
6 S. Z. Luo, Y. G. Zheng, W. Liu, H. M Jing, Z. M Yao, W. Ke,
Cavitation erosion behavior of CrMnN duplex stainless steel in
distilled water and 3% NaCl solution, J. Mater. Sci. Technol., 19
(2003), 346–350, doi:10.3321/j.issn:1005-0302.2003.04.016
7 W. Liu, Y. G. Zheng, C. S. Liu, Z. M. Yao, W. Ke, Cavitation erosion
behavior of Cr-Mn-N stainless steels in comparison with
0Cr13Ni5Mo stainless steel, Wear, 254 (2003), 713–722,
doi:10.1016/S0043-1648(03)00128-5
8 H. Berns, S. Siebert, High nitrogen austenitic cases in stainless
steels. ISIJ Inter., 36 (1996), 927–931, doi:10.2355/isijinternational.
36.927
9 W. T. Fu, Y. Z. Zheng, X. K. He, Resistance of a high nitrogen
austenitic steel to cavitation erosion, Wear, 249 (2001), 788–791,
doi:10.1016/S0043-1648(01)00811-0
10 P. Niederhofer, L. Richrath, S. Huth, W. Theisen, Influence of con-
ventional and powder-metallurgical manufacturing on the cavitation
erosion and corrosion of high interstitial CrMnN austenitic stainless
steels, Wear, 360–361 (2016), 67–76, doi:10.1016/j.wear.2016.
04.017
11 W. T. Fu, Y. B. Yang, T. F. Jing, Y. Z. Zheng, M. Yao, The resistance
to cavitation erosion of CrMnN stainless steels, J. Mater. Eng.
Perform., 7 (1998), 801–804, doi:10.1361/105994998770347396
12 D. J. Mills, R.D. Knutsen, An investigation of the tribological
behaviour of a high-nitrogen Cr-Mn austenitic stainless steel, Wear,
215 (1998), 83–90, doi:10.1016/S0043-1648(97)00273-1
13 J. F. Santos, C. M. Garzón, A. P. Tschiptschin, Improvement of the
cavitation erosion resistance of an AISI 304L austenitic stainless
steel by high temperature gas nitriding, Mater. Sci. Eng. A, 382
(2004), 378–386, doi:10.1016/j.msea.2004.05.003
14 D. H. Mesa, C. M. Garzón, A. P. Tschiptschin, Influence of cold-
work on the cavitation erosion resistance and on the damage
mechanisms in high-nitrogen austenitic stainless steels, Wear, 271
(2011), 1372–1377, doi:10.1016/j.wear.2011.01. 063
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938 937
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
15 Y. X. Qiao, S. Wang, B. Liu, Y. G. Zheng, H. B. Li, Z. H. Jiang,
Synergistic effect of corrosion and cavitation erosion of high
nitrogen stainless steel, Acta Metall. Sin., 52 (2016), 233–240,
doi:10.11900/0412.1961.2015.00282
16 A. Al-Hashem, P. G. Cacere, A. Abdullah, H. M. Shalaby, Cavitation
corrosion of duplex stainless steel in seawater, Corrosion, 53 (1997),
103–113, doi:10.5006/1.3280438
17 C. T. Kwok, F. T. Cheng, H. C. Man, Synergistic effect of cavitation
erosion and corrosion of various engineering alloys in 3.5% NaCl
solution, Mater. Sci. Eng. A, 290 (2000), 145–154, doi:10.1016/
S0921-5093(00)00899-6
18 T. H. Lee, C. S. Oh, C. G. Lee, S. J. Kim, S. Takaki, Precipitation of
-phase in high-nitrogen austenitic 18Cr-18Mn-2Mo-0.9N stainless
steel during isothermal aging, Scripta Mater., 50 (2004), 1325–1328,
doi:10.1016/j.scriptamat.2004.02.013
19 H. Y. Ha, H. S. Kwon. Effects of Cr2N on the pitting corrosion of
high nitrogen stainless steels, Electrochimica Acta, 52 (2007),
2175–2180, doi:10.1016/j.electacta.2006.08.034
20 S. Z. Luo, M. C. Li, W. Ke, Z. M. Yao, Y. G. Zheng, Effect of cavi-
tation on corrosion behavior of 20SiMn low-alloy steel in 3% sodium
chloride solution, Corrosion, 59 (2003), 597–605, doi:10.5006/
1.3277590
21 Y. G. Zheng, S. Z. Luo, W. Ke, Effect of passivity on electrochemical
corrosion behavior of alloys during cavitation in aqueous solutions,
Wear, 262 (2007), 1308–1314, doi:10.1016/j.wear.2007.01.006
22 B. Vyas. I. L.H. Hansson, The cavitation erosion-corrosion of
stainless steel, Corro. Sci., 30 (1990), 761–770, doi:10.1016/0010-
938X(90)90001-L
23 J. Basumatary, M. Nie, R. J. K. Wood, The Synergistic Effects of
cavitation erosion–corrosion in ship propeller materials, J. Bio.
Tribo. Corro., 1 (2015), 1–12, doi:10.1007/s40735-015-0012-1
24 R. J. K. Wood, S. A. Fry, The synergistic effect of cavitation erosion
and corrosion for copper and cupro-nickel in seawater, J. Fluids
Eng., 111 (1989), 271–277, doi:10.1115/1.3243641
25 S. Hong, Y. P. Wu, J. Zhang, Y. G. Zheng, J. Lin, Synergistic effect
of ultrasonic cavitation erosion and corrosion of WC-CoCr and
FeCrSiBMn coatings prepared by HVOF spraying, Ultrason. Sono-
chem., 31 (2016), 563–569. doi:10.1016/j.ultsonch.2016.02.011
Y. X. QIAO et al.: CAVITATION EROSION PROPERTIES OF A NICKEL-FREE HIGH-NITROGEN Fe-Cr-Mn-N STAINLESS STEEL
938 Materiali in tehnologije / Materials and technology 51 (2017) 6, 933–938
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
D. R. PONNUSAMY RAJARATHNAM, M. JAYARAMAN: INVESTIGATION OF THE WEAR BEHAVIOUR OF AN AISI 1040 ...
939–944
INVESTIGATION OF THE WEAR BEHAVIOUR OF AN AISI 1040
FORGED STEEL SHAFT WITH PLASMA-SPRAY
CERAMIC-OXIDE COATINGS FOR SUGAR-CANE MILLS
RAZISKAVA OBRABE AISI 1040 KOVANE JEKLENE GREDI S
KERAMI^NIMI OKSIDNIMI PREVLEKAMI ZA MLINE ZA
MLETJE SLADKORNEGA TRSA
Duraisamy Revathi Ponnusamy Rajarathnam1, Murugesan Jayaraman2
1Paavai Engineering College, Department of Mechanical Engineering, Namakkal District, India
2Velalar College of Engineering and Technology, Department of Mechanical Engineering, Erode District, India
drprajamalathi@yahoo.co.in
Prejem rokopisa – received: 2017-03-27; sprejem za objavo – accepted for publication: 2017-05-19
doi:10.17222/mit.2017.035
In this investigation, ceramic oxide powders, alumina, titania, chromia, alumina-titania, alumina-chromia and titania-chromia,
were coated for a thickness of 200 μm on an AISI 1040 forged steel substrate by means of an atmospheric plasma spraying
method. Ni-Cr was used as an intermediate bond coat of thickness 20 μm over the substrate to improve the coating adhesion.
Pin-on-disc apparatus was employed for a dry wear test as per the American Society for Testing and Materials G99 standards for
a constant load of 10 N, at different sliding distances of 1000 m, 2000 m and 3000 m, respectively. The investigation shows that
the microstructure, coating thickness, porosity, surface roughness and hardness influence the wear rate. Before and after the
wear tests, surface roughness measurements were carried out by using a talysurf instrument on the specimens. It is shown that
the highest value (20.89 μm) was obtained for the coating of alumina-titania. The practical results show that the pure chromia
coated specimen has a very good wear-resistance property compared to the ceramic oxides. This suggests that surface coating
with pure chromia on the top mill roll shaft of sugar industries enhanced the wear resistance.
Keywords: alumina, titania, chromia, atmospheric plasma spray, pin-on-disc, wear, Talysurf profilometer
V raziskavi so bili oksidni pra{ki: glinica, titan, krom, aluminijev oksid, aluminij-krom, prevle~eni z 200 μm na AISI 1040
podlago kovanega jekla z metodo napr{evanja s plazmo. Ni-Cr smo uporabili kot vmesni vezni premaz z debelino 20 μm nad
podlago za izbolj{anje oprijemljivosti prevleke. Pin-on-disk aparat je bila uporabljen za preskus suhe obrabe, v skladu s
standardi G99 Ameri{kega zdru`enja za testiranje in materiale, s konstantno obremenitvijo 10 N, na razli~nih drsnih razdaljah
1000 m, 2000 m in 3000 m. Preiskava je pokazala, da so mikrostruktura, debelina prevleke, poroznost, povr{inska hrapavost in
trdota vplivali na stopnjo obrabe. Pred in po testih obrabe, so bile meritve vzorcev povr{inske hrapavosti izvedene z uporabo
Talysurf instrumenta. Izkazalo se je, da je najve~ja vrednost (20,89 μm), pridobljena s prevleko iz aluminijevega
oksida-titanovega dioksida. Prakti~ni rezultati ka`ejo, da ima s ~istim kromom prevle~en vzorec zelo dobro odpornost na obrabo
kot tisti s kerami~nimi oksidi. Ka`e, da povr{inska prevleka s ~istim kromom na zgornji gredi mlina v sladkorni industriji
pove~a odpornost proti obrabi.
Klju~ne besede: aluminij, titan, krom, atmoferski plazma sprej, spoj na disk, obraba, Talysurf profilometer
1 INTRODUCTION
In many sugar industries, the top mill roller shaft,
used to crush sugarcane, is made up of AISI 1040 forged
carbon steel as this medium carbon, tensile steel shows
good strength, toughness and wear resistance. The roller
shaft has to operate under critical working conditions
such as heavy load, high speed, temperature and chemi-
cal environment, while it crushes the raw sugar cane to
extract the sugar cane juice. Hence, surface hardening of
the shaft is a must to improve the wear resistance as they
suffer from various types of degradation. Generally, the
shaft diameter will decrease due to continuous rotation
with a speed of 4 min–1 and accumulation of various im-
purities such as bagasse, ferrous and non-ferrous metals
and also due to improper lubrications in between the
journal bearing and the shaft. Hence, the shaft surface at
the pinion end should be coated with ceramic materials
with a good wear-resistance property.
The coating layer is very important because it
enhances the wear resistance of the metal substrate of
AISI 1040 forged steel to increase its life and efficiency.
Some of the most commonly used ceramic materials in
industrial applications are alumina (Al2O3), titania
(TiO2), Chromia (Cr2O3). S.-H. Yao1 studied nanostruc-
tured Al2O3 with 13 % of mass fractions of TiO2 coatings
and found that they showed better performance in
hardness and wear. Y. Sert et al.2 studied the wear resis-
tance of the plasma sprayed alumina – titania, titania,
chromia and chromia – titania and found the effect of
TiO2 content on Al2O3–TiO2 and Cr2O3–TiO2 coatings on
Al-based substrate, and concluded that hardness, coating
density and wear resistance changed with the TiO2
content.
Materiali in tehnologije / Materials and technology 51 (2017) 6, 939–944 939
MATERIALI IN TEHNOLOGIJE/MATERIALS AND TECHNOLOGY (1967–2017) – 50 LET/50 YEARS
UDK 620.1:620.193.95:669.1.017:621.926 ISSN 1580-2949
Original scientific article/Izvirni znanstveni ~lanek MTAEC9, 51(6)939(2017)