refractory material; borides used as a braze to join molybdenum, tungsten, and tantalum, and niobium parts for electronic, corrosion, and abrasion protection, used as a sputtering target with 99.5% purity to produce films which may be wear-resistant and semiconducting [CER91] [HAW93] [KIR78]
Corroded by molten metals Al,
Mg, V, Cr, Mn, Fe, Ni, Cu, Nb,
Mo, and Ta; corrosion resistant
to molten Cd, Sn, Bi, and Rb
Brazes to join molybdenum, tungsten, tanta-lum, and niobium parts, especially electronic com-ponents, corrosion and abrasion-resistant parts, cut-ting tools, refractory cermets.
Poison by intratracheal
route. Moderately toxic by ingestion and
intraperitoneal routes. When heated to
decomposition it emits toxic fumes of boron
and Mo.
