Superior No. 601B/3411 is a boron-modified, hi-temp silver brazing paste flux that meets AMS 3411 specifications. Whereas the typical silver brazing white flux (see Silver Brazing White Flux Paste) is active to 870°C/1600°F, No. 601B/3411 black brazing flux paste is active to 980°C/1800°F.
Black Hi-Temp Brazing Flux #601B/3411 – Solder Flux –