DEVELOPMENT OF LOW TEMPERATURE BRAZING OF TUNGSTEN FOR HIGH TEMPERATURE SERVICE
SOLAR SAN DIEGO CALIF
Pagination or Media Count:
The platinum-alloy reactive braze s stem PtB-W is being investigated to 1 studythe effect of B content, 2 study the effect of mode of W addition, 3 develop diffusion treatment, 4 determine optimum joint thickness, an 5 0 develop alloys based on information derived from preceding studies. Preliminary tests on Pt-2 to 6 5b indicate that the maximum usable B content is about 4.5. The Pt-3.6B alloy was used in studying the effect of the mode of W addition. The particle size of the W powder is not critical for sizes below 74 microns for heating rates in the 25 to 200 Fmin range the amount of W powder reactant added is critical. Study on diffusion treatments is dependent on the B and W studies, however, preliminary work on recrystallization cycles was begun with 0.020in.-gage W sheet samples heated at various temperatures and times in an inert atmosphere. Four cycles were completed 1 2300 F, 10 min, 2 2400 F, MIN, 3 2400 F, 10 min, an 4 2500 F, 1 min. None of these cycles resulted in serious recrystallization although the latter 2 appeared to be in the beginning stages.