Metal-carbon and metal carbide-carbon eutectic fixed points as high-temperature standards

Abstract

Results of scale uncertainty simulations using metal-carbon (M-C) and metal carbide-carbon (MC-C) eutectic fixed points showed that extension of the fixed-point temperature range to above 2500/spl deg/C is the key to the improvement of the scale. From this viewpoint /spl delta/(Mo carbide)-C, TiC-C and ZrC-C eutectics were investigated by radiation thermometry. The observed melting temperatures were 2583/spl deg/C, 2761/spl deg/C and 2882/spl deg/C, respectively. The results indicate that MC-C eutectics can establish a new series of high-temperature fixed points above 2500/spl deg/C.