... (%,min): 99.93Impurity content(%,max):Si 0.005, Al 0.0005, Fe 0.005, Cu 0.005,Mg 0.005, Ni ... , P 0.005,Ca 0.001, Pb 0.0005, C 0.005, Bi 0.0005, Sb 0.005,Ti 0.0015, V ... 0.0015,Co 0.0015,Bi 0.0005,Sn 0.0005 O 0.005, W 0.15.certification:ISO9001:2008 ...