フラックス添加によるステンレス鋼の焼結促進機構 Mechanism of Enhanced Sintering of Stainless Steel by Fluxing
A small amount of borax enhanced the sintering of SUS316L stainless steel powder compacts. The compacts of the -100mesh water-atomized powder with 2mass%Na<SUB>2</SUB>B<SUB>4</SUB>O<SUB>7</SUB> were sintered at different temperatures in vacuum. SEM micrographs and EPMA or EDX figures of the samples indicate that the silica-based oxide film on the surface of the steel particles has dissolved into the melted flux or borax at 1070K, that Cr<SUB>2</SUB>B particles have precipitated from the steel matrix while silicon and manganese have concentrated into the flux following a steel/flux reaction at 1270K, and that a Fe-Cr-B eutectic liquid has been formed and the Cr<SUB>2</SUB>B particles have disappeared above 1470K. Sintering at 1620K for 60min resulted in the highest density of compacts with almost no vacant pores. The formation of a Fe-Cr-B eutectic liquid may have caused the enhancement of densification by the capillary-force effect of the liquid.
粉体および粉末冶金 43(2), 241-248, 1996-02-15
Japan Society of Powder and Powder Metallurgy