Chromium-containing diffusion coatings for metals

摘要

Cr diffusion coatings are formed on Fe, Ni, Co or a metal having a melting point above that of iron e.g. Mo, W, Ti, Zr, Hf, V, Nb, Ta by immersing the substrate in a molten bath comprising Cr or Cr2O3 dissolved in molten Ca, and an alkali metal under an inert atmosphere to prevent oxidation. The coating may contain Ni. The melt may be in Fe, Ni or Ta container which is vibrated or subject to rolling and rocking motion in a tube furnace. Batch, semi-continuous and continuous coating are referred to.