Comparative Method and Choice of Standards for Thermal Conductivity Determinations

An improved version of the comparative method thermal conductivity apparatus was designed. Its accuracy was determined by measuring the conductivity of alumina with standards made of the same alumina and by cross-checking the conductivities of alumina, forsterite, Pyroceram Code 9606, and zirconia. The thermal stabilities of Pyroceram Code 9606 and zirconia were examined to establish their values as thermal conductivity reference materials. It was concluded that: (1) With this apparatus accurate thermal conductivity data can be obtained and (2) Pyroceram Code 9606 can be recommended for use as a primary standard for the low thermal conductivity range.