Asaoka K
Tokushima University, School of Dentistry, Department of Dental Engineering, Japan.
Dent Mater J. 1997 Jun;16(1):78-86. doi: 10.4012/dmj.16.78.
Thermal diffusivity and specific heat of four groups of dental casting alloys (Ag-based, Au-Pd, high karat and Ni-based alloys) were determined. Measurements were carried out from room temperature to 750 degrees C in an evacuated electric furnace with a laser flash thermal constant analyzer. There was no significant difference between the values of thermal diffusivity in the Ag-based and high karat alloys; 18-24 and 40-53 mm2/s, at room temperature and at 600 degrees C, respectively. For Au-Pd and Ni-based alloys, diffusivity was 8-12 and 3-4 mm2/s at room temperature, and 19-22 and 5-6 mm2/s at 600 degrees C, respectively. The thermal diffusivity of the alloys was significantly low compared to that of the pure-metals of which they were composed. Specific heat was determined as 0.14-0.16, 0.24-0.34, 0.17-0.19 and 0.45-0.51 kJ/(kg.K) for high karat, Ag-based, Au-Pd and Ni-based alloys, respectively, at room temperature. Oxidation of the Ni-based alloy at elevated temperature affected the value of specific heat measured.
测定了四组牙科铸造合金（银基、金钯合金、高K合金和镍基合金）的热扩散率和比热容。测量在配有激光闪光热常数分析仪的真空电炉中，从室温至750摄氏度进行。银基合金和高K合金的热扩散率值在室温下分别为18 - 24mm²/s，在600摄氏度时分别为40 - 53mm²/s，二者之间无显著差异。对于金钯合金和镍基合金，室温下扩散率分别为8 - 12mm²/s和3 - 4mm²/s，600摄氏度时分别为19 - 22mm²/s和5 - 6mm²/s。与构成这些合金的纯金属相比，合金的热扩散率显著较低。室温下，高K合金、银基合金、金钯合金和镍基合金的比热容分别测定为0.14 - 0.16、0.24 - 0.34、0.17 - 0.19和0.45 - 0.51kJ/(kg·K)。镍基合金在高温下的氧化影响了所测比热容的值。
