Abstract
The bonding of several kinds of pure metals and commercial steels was conducted in a hot salt bath containing 40wt% of carborundum and 60wt% of borax at 1, 000°C.
Boride layers having hardness higher than 2, 000VHN and of less than 15μ in thickness were produced by this process for W, Mo, Ta, and Cr; while for Co, Ni, Zr, and V, the hardness was 1, 200-1, 600VHN and the thickness was more than 100μ.
The boride layers in the former group of metals were composed of higher boride compounds such as WB, CrB, and TaB; while the latter were lower boride compounds such as CO2B, Ni2B, Zr2B, arid V2B.
As for commercial steels, thin boride layers were produced for some steels such as 18-8 stainless steel, 13-Cr stainless steel, and high speed steels; while thick layers were produced for other steels such as steel used for nitriding and high carbon steels. The difference between the both groups of steels would be due to the difference in W, Mo, or Cr content of the steels.
