Gas phase borosiliconization of ferrous surfaces

摘要

The surface properties of iron or ferrous alloy are improved by borosiliconizing the surface by contact with a stream of reducing gas containing hydrogen, optionally with an inert gas, to which a gaseous halide or hydride of boron and silicon have been added, either together or sequentially. The temperature of treatment is elevated, e.g. above 350 DEG C., but below 1200 DEG C. Diffusion coatings of both boron and silicon are formed in the ferrous surface. Typical surces of boron and silicon inlude boron trichloride, diborane and silane.