Thermal Conductivity Testing of Metals at Temperatures up to 200 ºC
Thermal conductivity measurements were performed at increasing temperatures on three different metals using the Hot Disk TPS 2200 thermal conductivity instrument. The Hot Disk TPS method can be used to simultaneously measure thermal conductivity, thermal diffusivity and volumetric heat capacity of solids, liquids, pastes, and powders without the need for calibration or contact agents. The TPS 2200 thermal conductivity system can be used for testing of materials with thermal conductivities ranging from 0.03 to 500 W/m·K.
The TPS standard (bulk) module was used for the thermal conductivity testing. In this module, two identical samples are placed on either side of the TPS sensor and light pressure is applied to ensure that there is good contact between the samples and the sensor.
The three samples that were tested for thermal conductivity were bronze, 4130 steel, and 316 stainless steel (Figure 1). Each sample was tested at temperatures of 21, 50, 100, and 200 ºC to determine how the thermal conductivity of each sample is affected by temperature. Five measurements were performed for each sample at each temperature and the average thermal conductivity at each temperature was calculated. The results were plotted and are shown in Figures 2-4.
As can be seen in the figures, the thermal conductivity of bronze increased with increasing temperatures up to 100 ºC, remained relatively constant at 150 ºC, and then began to increase once again. 4130 steel showed an increasing trend in thermal conductivity with temperatures up to 100 ºC, and it began to decrease slightly at higher temperatures. The thermal conductivity of 316 stainless steel sample increased with increasing temperature over the entire temperature range studied.