1240 KB20 KB200020242014Šín, PeterŠtubňa, IgorTrník, AntonViljus, Martštevilka:3letnik:48str. 331-336COBISSID:1054890ISSN:1580-2949URN:URN:NBN:SI:doc-KVCG3W4SenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijealumina porcelainaluminijev oksidporcelanShore hardnesstrdota po Shoreutrdota po VickersuVickers hardnessYoungov modulYoung's modulusThe effect of the firing temperature on the hardness of alumina porcelain| Vpliv temperature žganja na trdoto porcelana iz aluminijevega oksida|Green alumina porcelain samples containing kaolin (27 %), Al2O3, grog (50 %) and feldspar (23 %) were fired at temperatures between 300 °C and 1250 °C with a heating and cooling rate of 5 °C/min. The Shore hardness and the Vickers hardness of the fired samples were measured at room temperature. Both hardnesses of the green alumina porcelain samples are low and remain approximately constant up to 400 °C when dehydroxylation begins. Between 400 °C and 700 °C both hardnesses slightly increase. Above 700 °C, they increase exponentially. This is explained by sintering and high-temperature reactions in metakaolinite. The dependencies between both hardnesses, Shore and Vickers, and the firing temperature are very similar, i.e., the Shore hardness and the Vickers hardness reflect changes in the sample in the same manner. The Vickers hardness is much more sensitive to the firing temperature. Its values after firing at 1250 °C are 130 times higher than those measured at room temperature. However, the values of the Shore hardness are only four times higher. The relationship between the Young%s modulus and the Shore hardness and the Vickers hardness can be fitted by power-regression functionsSurovi vzorci porcelana, ki vsebujejo kaolin (27 %), Al2O3 in gline (50 %) ter glinenec (23 %), so bili žgani pri temperaturah med 300 °C in 1250 °C s hitrostjo ogrevanja in ohlajanja 5 °C/min. Pri sobni temperaturi je bila pri žganih vzorcih izmerjena trdota po Shoreu in Vickersu. Obe trdoti surovega porcelana na osnovi aluminijevega oksida sta nizki in ostajata relativno konstantni do temperature 400 °C, ko se začne dehidroksilacija. Med 400 °C in 700 °C obe trdoti nekoliko narasteta. Nad 700 °C trdoti naraščata eksponencialno. To si razlagamo s sintranjem in z visokotemperaturnimi reakcijami v metakaolinitu. Odvisnosti med obema trdotama po Shoreu in Vickersu ter temperaturo žganja so zelo podobne, kar pomeni, da trdoti po Shoreu in Vickersu izražata spremembe v vzorcu na enak način. Trdota po Vickersu je bolj občutljiva za temperaturo žganja. Njena vrednost po žganju pri 1250 °C je 130-krat višja kot trdota, izmerjena pri sobni temperaturi. Vrednosti trdote po Shoreu so samo 4-krat višje. Odvisnost med Youngovim modulom, trdoto po Shoreu in trdoto po Vickersu je mogoče ugotoviti s funkcijami regresijeTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije