FORMATION OF BORIDE LAYER ONTO ALLOY STEEL PRODUCT OR TITANIUM ALLOY SURFACE

摘要

PURPOSE:To obtain the material which has a boride layer and has uniform quality and high fatigue strength by simultaneously or alternately executing vapor deposition of boron and irradiation of inert gaseous ions, thereby forming a mixing layer on an alloy steel product or titanium alloy surface. CONSTITUTION:Vapor 4 of the boron generated from a crucible 5 for evaporation having an electron gun, etc., is deposited by evaporation on a substrate 1 consisting of the alloy steel or titanium alloy on a substrate holder 3 in a vacuum vessel (not shown). On the other hand, the inert gas a supplied from a gas cylinder 8 for an ion source is ionized by an ion source 7 consisting of a plasma chamber 9, etc., having a heater 11, a DC magnet 12, etc., and further, the ions are accelerated by a power source 10 for ions. The substrate 1 is irradiated with the accelerated ions 6 formed in such a manner. The mixing layer composed of the boron is formed on the substrate 1 surface by simultaneously or alternately executing the vapor deposition of the above- mentioned boron and the irradiation of the inert gaseous ions and the vapor deposited layer of boron is formed on this layer at need. The above-mentioned material surface is reformed by forming the boride layer thereon in this way and residual compressive stresses are imparted thereto without strains, by which the fatigue strength is improved.