Determination of the thermal conductivity of nickel – zirconia cermets by a laser-flash method
Wangyu Hu, Hengrong Guan, Xiaofeng Sun, Shizhuo Li
A study of the thermal conductivity of nickel – zirconia cermets is reported. The following samples are investigated: nine types of one-layer nickel – zirconia composites with various nickel contents, four types of two-layered composites, and a three-layered composite. The measurements were performed with a conventional laser-flash apparatus with rear-side detection of the temperature response with an infrared detector. The thermal diffusivity or conductivity of one-layer nickel – zirconia composites is determined directly by the use of the half-rise time, t1/2. For the case of multilayered materials, the data obtained are used to verify the thermal contact resistance (TCR). The measured results show that the thermal diffusivity and conductivity vary linearly with the measured temperature. The TCR is 0 – 0.09 K cm2 W-1 for the duplexes including a nickel layer and 0 – 0.9 K cm2 W-1 for other duplexes. The TCR of the three-layered sample is 0.7 – 1.6 K cm2 W-1, much higher than that of the duplexes.