Wettability by Liquid Metals, Metalization, and Brazing of Barium Titanate Ceramics A study investigates the contact interaction and wetting of BaTiO3 perovskite ceramics by liquid metals

Detailed investigations, including wetting studies by liquid metals and metal coatings deposition onto ceramic surfaces and brazing processes, were carried out for semiconducting and ferroelectric perovskite ceramic states of barium titanate (BaTiO3). Pure metals (Cu, Ag, Au, Ge, Sn, Pb, Ga, In, Al, Si, Ni, Co, Fe, Pd) and Ti-containing alloys based on In and binary Cu-Sn, Cu-Ga, and Cu-Ag systems were investigated under high vacuum for the semiconducting BaTiO3-x surface. The degree of wettability correlates approximately with the chemical affinity of the liquid metal phase to oxygen (wetting increases when the liquid metal affinity to oxygen increases). Addition of Ti to the liquid metal phase increases capillary properties and adhesion in the system under investigation. Investigations of the wettability of ferroelectric BaTiO3 ceramics were performed in air gaseous media by alloys Ag-Cu-O. Oxygen in the gaseous media preserves stoichiometric composition of barium titanate and being dissolved in Ag-Cu alloys promotes BaTiO3 wetting. For the first time, wettability experiments in liquid metal/ceramic material systems (BaTiO3 in this case) were carried out when the gaseous phase was pure oxygen. At greater oxygen partial pressure (1 atm for O-2 comparing to 1/5 atm for air), wettability further increases significantly. Vacuum brazing technology for semiconducting materials and joining processes in air or pure oxygen atmosphere for ferroelectric ceramic materials based on BaTiO3 have been developed. Various detailed brazing models of BaTiO3 and BaTiO3-x were created.