A study of chromium on wettability of liquid copper on alumina ceramics

摘要

The wetting characteristics of metals on ceramics is an important factor of many processes such as brazing, bonding, liquid-phase sintering of infiltrating when metals and ceramics are needed to be combined together. However, most of the pure metals exhibit obtuse contact angles on ceramics and thus some addition of active metals are required to enhance their wettability. In this study, the effect and role of an active element such as chromium has been evaluated as an additive to promote the wetting of liquid copper on alumina by a sessile drop method. It is found that an appropriate percent of chromium addition can improve the wettability of copper on alumina after a long exposure at high temperature, According to SEM observation, chromium inclines to segregating in the interface area between solidified copper droplet and alumina substrate. In order to further understand the modification mechanism of chromium, XRDand TEM are performed to identify the created phases and analyze the reactions in the interface. Finally, a model for chromium effect on the reactive wetting is proposed. [References: 9]