Ceramic-to-metal brazing and soldering use a metal or alloy (often eutectic) in the form of a wire, paste, or preform with a lower melting temperature than either of the parts to be joined. The braze or solder is placed between the faces to be joined and heated. Upon melting, the braze or solder metallurgically wets both surfaces. Upon cooling, the braze or solder solidifies to form a strong and hermetic joint. Brazes and solders naturally wet to many metals. However, many metals with robust native oxides require Nickel and Gold plating to increase the wettability. Bare ceramics require metallization in order for the braze or solder to sufficiently wet. To metallize, we use one of the metallization techniques listed in the Metallization section under Capabilities.
Sealing techniques that occur at temperatures below 450°C are called soldering (often flux-less soldering at STC Material Solutions) or soft brazing. Sealing techniques performed at temperatures greater than 450°C are called brazing.