DEVELOPMENT OF A NEW THERMOGRAVIMETRIC SYSTEM FOR PERFORMING CONSTANTRATE THERMAL-ANALYSIS (CRTA) UNDER CONTROLLED-ATMOSPHERE AT PRESSURESRANGING FROM VACUUM TO 1-BAR

A CI electronic microbalance which allowed sample weights up to 5 g to be measured with a maximum sensitivity of 1 mug has been used to deve lop a new constant rate thermal analysis (CRTA) technique. This permit ted a constant rate of change of weight Absolute value of C greater-th an-or-equal-to 10 mug min-1. Moreover, it has been extended to constan t rate jump thermal analysis (CRJTA). The microbalance is attached to a conventional system of vacuum and gas storage that allowed work to b e carried out under vacuum or under controlled atmosphere. The perform ance of the equipment was checked by studying both the thermal decompo sition of CaCO3 and the recombination reaction of silicon and nitrogen , producing Si3N4.