非酸化物セラミックス用焼結速度測定装置

抄録

A high-temperature dilatometer was assembled for studying the densification behavior of non-oxide ceramics up to 2300°C in 1MPa innert gas atmosphere. The accuracy of shrinkage up to 2300°C was better than 17.8×10^-3% for 40mm long samples including the base line drift and probable error. The accuracy of shrinking rate was better than 3.3×10^-3%·min^-1, where the base line drift was negligibly small. The shift of base lines estimated from the drift of shrinkage was also smaller than the probable error of shrinking rate. Heating rate affected the base line drift of shrinkage, while the probable error was not influenced. The accuracy of shrinkage and shrinking rate did not depend on the kind of atmospheric gas. With decreasing gas pressure, the accuracy was improved by the damped gas convection. The densif ication behavior of some kinds of silicon nitride and silicon carbide powder compacts was measured by using this equipment. The high accuracy was maintained for silicon carbide during measurement in spite of the large shrinkage and shrinking rate. The probable error for silicon nitride increased above 1600°C, because of the thermal decomposition and vaporization. The error was diminished by a numerical smoothing.