Wetting of Original and Metallized High‐Alumina Surfaces by Molten Brazing Solders

An apparatus using the sessile‐drop method is described for determining surface tension and wettability data of liquid‐solid systems at elevated temperatures in vacuum and in controlled atmospheres. The relative merits of some of the current methods of metallizing alumina ceramics are evaluated in terms of solder wetting. The wetting by molten brazing metals and alloys is reported as a function of time in terms of contact angle on surfaces of high‐alumina ceramics with and without various types of hightemperature metal coatings.