APA 7

Incusil-ABA alloys are used because of their ability to wet directly to PCD and CBN at reduced temperatures. Indium is used as a melting point depressant which decreases the liquidus of the filler metal. A braze range of 100-150 °F above the liquidus is beneficial for creating the reaction between the titanium and surface oxides. An increased soak time of 20 minutes also leads to a better reaction, and stronger braze joint. When wetting to a non-metalic surface, these ABA’s will wet in-place, but not flow through a joint by capillary, therefore it is recommended that the paste is applied to all surfaces which require wetting, prior to brazing. Suitable for use in all vacuum brazing applications as well as under partial pressure of argon gas. Brazing of active alloys under protective nitrogen atmosphere is not recommended. It is important to maintain a high purity, oxygen-free environment; any oxidation of reactive elements will limit alloy wettability across the non-metallic surface.

The properties of a brazed joint are dependent upon the base metal, joint design and brazing technique. For controlled atmosphere brazing or vacuum brazing the recommended radial joint clearance for silver base alloys fall within 0.0015 in. - 0.002 in. (0.038 mm - 0.051 mm.) range.