Electroless plating of Nb-Ni coatings from salt melt

摘要

Electroless plating of niobium on a nickel surface is investigated in NaCl-K2NbF7 halide melt containing 10-30 wt % K2NbF7 in the presence of metallic niobium powder. At a temperature of 750A degrees C, a nickel surface is covered by Nb-Ni coatings to a thickness of 20 mu m, which include NbNi3 and NbNi intermetallic compounds. They are characterized by low roughness and the lack of penetration defects. They protect nickel from corrosive dissolution in halide salt melts. The microhardness of the coatings is 8370 +/- 350 MPa and does not change over the layer thickness within the measurement error.