Influence of thermal treatment on CTO wettability

Calcium–titanium–oxygen precipitate (CTO) is well known for its notable electrorheological performance. The two main components of CTO particle are calcium oxalate dehydrate (COD) and titanium–oxygen precipitates (HTO). We systematically studied the wettability of these three compounds with silicon oil at different thermal treatment temperatures. We found that the wetting performance of the HTO decreases with increasing heating temperature, the same tendency as that of CTO particles. This discovery inferred that the wettability of CTO particles is dominated by HTO component. Thermal gravity analysis, X-ray diffraction, X-ray photoelectron spectroscopy as well as the wettability analysis were applied to demonstrate our proposition. The results revealed that HTO is decomposed into inorganic compounds like free carbon by thermal treatment, resulting in a decrease of the wettability of the CTO particles.