Gasanalyse beim Sintern von Hartmetall durch TA-imulation

Abstract

The processes taking place during outgassing and sintering of different hard metals are investigated by Simultaneous Thermal Analysis (Thermogravimetry and Differential Thermoanalysis) coupled with Mass Spectrometry. In this paper an overview on the application of these methods is given. The progress of gas reactions, their kinetics and the reaction products themselves are characterized more in detail. Main products of the outgassing during the sintering of hard metals are hydrocarbons, carbon monoxide, carbon dioxide and partly nitrogen. The outgassing during the sintering of conventional WC-Co hard metal is finished at relatively low temperatures (approximately 800‡C). The outgassing during the sintering of cermets and of hard metals containing mixed carbides takes place up to higher temperatures (partly up to the formation of the liquid phase). Critical temperature ranges of technological processes may be determinated.