Thermal Conductivity of Sintered Nickel Films Obtained with the HVOF Technique

Abstract

Thermal conductivity has been measured in the range 6–130 K on sheets of nickel 0.1 mm thick produced by sintering powder sprayed in layers with the HVOF detonation technique. This technique, which pertains to the thermal-spray family, uses a high-velocity jet of low-temperature (≈1000 °C) gas, obtained by detonation of propane in air, for carrying the powder. Sintering in a controlled-atmosphere furnace of the layer obtained in this way follows. The aim is to obtain a metal substrate with a thermal conductivity lower than that of the bulk material, for use in a certain number of applications that require metal substrates of the lowest thermal conductivity. The paper reports on the technique and on the results obtained on nickel using a modular thermal conductivity apparatus that is used simply by immersion in a liquid helium (or liquid nitrogen) standard storage dewar with a 50 mm neck and is fully run by a computer, allowing for routine measurements in the range 5–350 K with an uncertainty as low as ± 4% on silica. In the present work, uncertainty of the measurements on sintered nickel was ≈ ± 30%.