Zhong Hai-yun

A binder phase of TiO based cermets

A binder phase of TiO based cermets, a kind of imitated gold materials, was developed by adding active element Si to Fe-Cr alloy, and the related mechanisms were studied. The wettability, matching in thermodynamics and interfacial strength were investigated by the high temperature sessile drop method and element area scanning. The linear expansion coefficients of the materials were measured using TAH100 thermal analyzer. The results show that the wettability of Fe-Cr alloy on TiO are small, with a wetting angle about 90°. After adding some Si in Fe-Cr alloy, its wetting angle can be decreased to about 25°, the interfacial reactions can be prevented effectively and high interface binding can be formed. Fe-25%Cr-1.5%Si matches the thermal expansion coefficient of TiO, so it is a kind of relatively perfect binder for TiO based cermets imitated gold.

The wettability of Fe based alloy on TiO

For developing TiO based imitated gold materials, the wettabilities of Fe and Fe-Cr-Ni-Ti on TiO were studied. The results indicated that the wettabilities of Fe and Fe-Cr on TiO were poor, and their wetting angles were about 90° at melting point. The wetting angles reduced with the increase of wetting temperature, but the influence of temperature was small. Fe and Fe-Cr containing Cr 50% or less could react with TiO on the interface to form Fe2Ti and Ti2O3, but this did not improve the wettability effectively. When Ni-Ti was added into Fe-Cr alloy, Ni3Ti was formed on the interface, which can reduce the interface energy, improve the wettability, and prevent the formation of Fe2Ti and Ti2O3. The wetting angles could go down to about 40° when 3% Ni-Ti was added to Fe-Cr alloy.