Authors: Y Yamada Y Wang W Zheng N Sasajima
Publish Date: 2007/10/23
Volume: 28, Issue: 6, Pages: 2028-2040
Abstract
The authors recently reported the very first radiometric plateau observation of hightemperature fixed points of metalcarbide carbon peritectics These act in a similar way to the metal carbidecarbon eutectic points in the sense that they can be used at high temperature without being contaminated by their graphite crucibles The performance seems similar in terms of repeatability and plateau shape The peritectic transition temperatures are close to the transition temperatures of some of the metal carbidecarbon eutectics In this article results of further study to understand the melting and freezing involved in these fixed points are reported with the focus on the Cr3C2C peritectic point Difficulty in producing an ingot without voids was encountered To overcome this a filling technique that takes advantage of the capillary effect was devised Plateau shapes and microstructures observed with electronprobe microanalysis EPMA and backscattered electron imaging BSE for various filling methods were compared The observation of two fixedpoint plateaux one at the Cr3C2C peritectic point and the other at a lower temperature of the Cr7C3Cr3C2 eutectic point correlates to the presence of two kinds of domains in the observed microstructure The graphite crucible is shown to play an essential role in realizing peritectic plateaux of good quality
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