582 KB34 KB200020242014Cui, ZhengweiDong, ZhijunLi, WenLi, XuankeLiu, YueYuan, GuangmingZuo, Xiaohuaštevilka:1letnik:48str. 59-66COBISSID:1031338ISSN:1580-2949URN:URN:NBN:SI:doc-QYFLT4ASenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijeboron alloysborove zlitinecarbonizationdoped coal-tar pitchdopirana premogova katranska smolakarbonizacijaodpornost proti oksidacijioxidation resistancepirolizapyrolysissilicijeve zlitinesilicon alloysOxidation behavior of carbon-silicon and carbon-boron-silicon alloys derived from solvent-soluble silicon and boron-silicon-doped coal-tar pitches| Vedenje pri oksidaciji ogljik-silicijevih in ogljik-bor-silicijevih zlitin, pridobljenih iz raztopin premogove katranske smole, dopirane s topnim silicijem in bor-silicijem|The solvent-soluble silicon (Si) and boron-silicon (B-Si) doped coal-tar pitches were synthesized with the co-pyrolysis of a mixture of the toluene-soluble fraction of the coal-tar pitch (TSP), polycarbosilane and pyridine borane. The C-Si and C-B-Si alloys were obtained with a carbonization treatment of the synthetic Si and B-Si doped coal-tar pitches at 1000-1600 °C for 1 h. The physical properties of the Si and B-Si doped coal-tar pitches, such as the softening point, quinoline insolubles, the volatile content and the pyrolysis yield were determined. The influences of the pyridine-borane content in raw materials and the carbonization temperature on the composition, microstructure and oxidation resistance of the C-Si and C-B-Si alloys were investigated. The results show that the C-B-Si alloys are composed of SiC, B2O3 and carbon, while the silicon, boron and oxygen elements are uniformly dispersed in the carbon matrix. In most cases, the oxidation resistance of the C-B-Si alloy is better than that of the C-Si alloy, owing to the sintering-aiding action of B2O3 and the anti-oxidation synergism of the SiO2 and B2O3 formed during oxidation. The higher the carbonization temperature, the larger is the grain size of the SiC in the C-B-Si alloy. A large grain size leads to an increase in the initial oxidation temperature of the SiC, which is unfavorable for the formation of a protective glassy film on the surface of the C-B-Si alloys. As a result, the C-B-Si alloy obtained with the carbonization at 1200 °C shows a better oxidation resistance than that obtained with the carbonization at 1600 °C under the same oxidation conditionsTopila premogove katranske smole, dopirane s topnim silicijem (Si) in bor-silicijem (B-Si), so bila sintetizirana s kopirolizo mešanice v toluenu topne frakcije premogove katranske smole (TSP), polikarbonsilana in piridin borana. Zlitine C-Si in C-B-Si so bile dobljene s karbonizacijsko obdelavo premogove katranske smole, dopirane s sintetičnim Si in B-Si 1 h pri 1000-1600°C. Določene so bile fizikalne lastnosti premogove katranske smole, dopirane s Si in B-Si, točka mehčanja, trdni delci ogljika, vsebnost hlapnih snovi in izkoristek pirolize. Preiskovan je bil vpliv vsebnosti piridin boranav surovini in karbonizacijska temperatura na sestavo, mikrostrukturo in oksidacijsko odpornost zlitin C-Si in C-B-Si. Rezultati kažejo, da so zlitine C-B-Si sestavljene iz SiC, B2O3 in ogljika, pri čemer so elementi ogljik, silicij, bor in kisik enakomerno razpršeni po osnovi iz ogljika. Odpornost proti oksidaciji je v večini primerov pri zlitini C-B-Si boljša od zlitine C-Si zaradi dodatnega učinka B2O3 in protioksidacijske sinergije SiO2 in B2O3, ki nastajata med oksidacijo. Čim višja je temperatura karbonizacije, tem večja postajajo zrna zlitine SiC in C-B-Si. Večja kristalna zrna povzročijo povišanje temperature začetka oksidacije SiC, kar je neugodno za nastanek steklaste zaščitne plasti na površini zlitin C-B-Si. Rezultat tega je, da zlitina C-B-Si, dobljena pri karbonizaciji pri 1200 °C, pri enakih razmerah za oksidacijo kaže boljšo odpornost proti oksidaciji kot zlitina, pridobljena s karbonizacijo pri 1600 °CTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije