Evolved gas analysis in modelling studies of pre-sintering step in fabrication of ceramic alumina specimens

摘要

For modelling the pre-sintering procedures of high grade alumina ceramic, thermally evolved gases from alumina-organic binder mixtures released in flowing air have been analyzed and monitored by simultaneous thermogravimetry and differential thermal analysis coupled online with mass spectrometer (TG/DTA-EGA-MS) and FTIR spectroscopic gas cell (TG-EGA-FTIR) up to 700 ℃.rnElimination course of organic vapors and formation of CO_2 have been monitored and compared with the dynamics of overall weight loss (indicated by DTG curves) at constant heating rates. Below 280 ℃, elimination of organic vapors were dominant, while above 280 ℃ CO_2 was the main decomposition product, indicating that additional measures are to be taken to complete the burning out of organic vapors released at relatively low temperature in considerable amount during the pre-sintering process, meanwhile relatively high temperature and long durations are needed to obtain ceramics free from the residues of the moulding additives.