Abstract
Various members in the talc-willemseite series were obtained by hydrothermal synthesis under the conditions of 550°C, 500kg/cm2 (water vapour pressure) and 10 days. The products were examined by infrared absorption spectroscopy, X-ray diffraction technique, thermal analysis, heat treatment and electron microscopy.
Nickel contents of the products calculated from the intensities of the absorption bands in the OH stretching vibration region were in good agreement with those of starting materials.
Their DTA curves were characterized by the very large endotherm in the temperature range of 800-1000°C. The peak temperature shifted gradually to higher temperature from 862°C for talc to 945°C for willemseite with increasing nickel content, indicating that nickel rich members are thermally more stable than magnesium rich members. This behaviour was also confirmed by the results of the heat treatment.
