Fuji Oozx Inc.

Eiji Hirai

Takeji Kenmoku

Shinichi Umino

Yoshio Matsumura

Kazuyoshi Kurosawa

There is provided a new method of improving properties of the surface of an internal combustion engine valve made from titanium alloy, which comprises; the steps of (a) forming a surface undercoat layer of nickel on a surface of the engine valve; (b) heating the resulting nickel undercoated valve in vacuum or in an atmosphere of inert gas, at the temperature of 450.degree. C. to 600.degree. C., for one to four hours; (c) forming further a three component coat layer comprising nickel, phosphorus and particles of material selected from the group consisting of silicone carbide, silicone nitride, boron nitride, and the combination thereof, on the surface of the nickel undercoat layer; and (d) heating the resulting coat layer formed on the nickel undercoat layer, at the temperature of 350.degree. C. to 550.degree. C., for one to four hours, so as to make the particles of ceramic material uniformly and homogeneously dispersed in said coat layer.

Properties of the surface of a titanium alloy engine valve

There is provided a new structure of an engine valve made from titanium alloy, having three component coat surface layer formed on the surface of the reciprocating shaft thereof, wherein the composition of the three component coat surface layer comprises nickel, phospher and particles of material selected from the group consisting of silicone carbide, silicone nitride, boron nitride, and the combination thereof; said particles are uniformly dispersed in said coat surface layer; and said coat surface layer is formed via a binding layer or directly on the surface of the shaft.

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Atsugi, Japan

Eiji Hirai