Research and Development of Refractory Oxidation-Resistant Diborides. Part II,Volume V: Thermal,Physical,Electrical and Optical Properties.

摘要

Thermal conductivity data were measured from 100to 1000C and were calculated from thermal diffusivity,specific heat and density data from 1000to 2000C for compositional and microstructural variations of ZrB2and HfB2with SiC and/or C additives varying in total content from 20to 34volume percent. The specific heat data were obtained from drop calorimetry methods for selected compositions and by calculations from constituent values for other compositions. Linear expansion data were obtained from room temperature to 2000C by direct-view and differential dilatometry for compositions of ZrB2with SiC and/or C additives. Electrical resistivity data were obtained from room temperature to 1000C;all compositions displayed positive temperature coefficients. Total normal emittance data were measured from 1600to 2300C for unoxidized diboride compositions. (Author)