tantalum bar ASTM B365 standard:ASTM B365 RO5200,RO5400 RO5252 (Ta-2. ... (Ta-10W) purity:99.95%,99.99% ISO9001:2008 tantalum bar ASTM B365Introduction:Tantalum is dark, dense, ductile, very hard, easily ... tendency of tantalum to form a protective oxide surface layer, using tantalum powder, pressed into a pellet shape, as one "plate ...