Thermal diffusivity and specific heat of dental casting alloys at room and elevated temperatures.
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.
Asaoka
K
K
Tokushima University, School of Dentistry, Department of Dental Engineering, Japan.
D003722:Dental Alloys / Q000737:chemistry*; D006047:Gold Alloys / Q000737:chemistry; D006358:Hot Temperature; D007834:Lasers; D008422:Materials Testing / Q000379:methods; D009532:Nickel / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013814:Thermal Conductivity; D013816:Thermodynamics
D003722:Dental Alloys; D006047:Gold Alloys; D012834:Silver; D009532:Nickel