A SIMPLE AND SENSITIVE METHOD FOR SIMULTANEOUS HIGH-TEMPERATURE X-RAY-POWDER DIFFRACTION AND THERMOGRAVIMETRIC ANALYSIS

An apparatus is described for simultaneous high-temperature X-ray powd er diffraction and thermogravimetric studies, based on a Guinier-Lenne focusing powder camera and an analytical chemical balance. No modific ations are required to either instrument and the method would be readi ly useable with many other types of high-temperature powder diffractio n systems. The technique is illustrated by a study of the dehydration reactions in an artists' plaster containing gypsum. A sensitivity to c hanges in weight approaching 100 mu g in a 12.5 mg sample was achieved over a period of 60 h.