Titanium metallization of alumina ceramics by molten salt reaction

In this work, we reported a novel method that is flexible to metallize alumina ceramics with complex surface. Through Ti2+ disproportionation occurred in molten NaCl-KCl-K2TiF6 bath, the dense Ti layer was deposited on Al2O3 ceramics surface with strong adhesion. The effects of reaction temperature, time and initial K2TiF6 concentration on deposition rate were investigated. As-prepared coatings compose of bilayer structure of reactive Ti2O phase, namely, the outer layer with coarse grains and the inner layer with fine grains. The wettability of eutectic Ag72Cu28 and Pb37Sn63 alloys with metallized Al2O3 ceramics was measured by using sessile drop method and compared with that of original ceramics. The results show that the metallized Al2O3 surface could be reactively wetted well with Ag72Cu28 and Pb37Sn63 alloys. The contact angles lowered to 35° and 8°, respectively, when temperature rose to 900 °C, showing significant enhancement of wettability after Ti metallization by molten salt reaction.