Abstract: A position control device includes: a storage unit that stores a deviation, between time from transmitting an ultrasonic wave until receiving a reflected wave and a reference time, in an (n?1)-th line when an ultrasonic probe unit scans the (n?1)-th line of a surface of a sample before the ultrasonic probe unit moves to an n-th line; and a processing unit that determines a position of the ultrasonic probe unit when the ultrasonic probe unit scans the n-th line of the surface based on the deviation in the (n?1)-th line, and calculates a deviation in the n-th line between time from transmitting an ultrasonic wave until receiving a reflected wave and the reference time when the ultrasonic probe unit scans the n-th line of the surface. The processing unit determines the position of the ultrasonic probe unit in a direction perpendicular to the surface to make the deviation zero.

Abstract: A new nitriding process by using a salt bath to produce iron and steel parts having excellent abrasion resistance and corrosion resistance includes forming an iron lithium complex oxide layer at the outermost surface of the iron part by immersing the iron and steel parts in a salt bath containing cationic component of Li, Na and K and anionic components of CNO?and CO32?, where hydroxide compound selected from lithium hydroxide, sodium hydroxide and potassium hydroxide are added to the salt bath. Materials being in a hydrated state or in a free water containing state can be used for preparation or replenishing of the salt bath. Moistened air of (1×10?2 kg·H2O)/(1 kg dry air) can be used for mixing the salt bath. Containing ratio of Li, Na, K is preferable where a solidifying temperature of the mixture of carbonates of Li, Na, K in that ratio is lower than 500° C.

Abstract: A new nitriding process by using a salt bath to produce iron and steel parts having excellent abrasion resistance and corrosion resistance are explained. A iron lithium complex oxide layer are formed at the outermost surface of the iron part by immersing the iron and steel parts in a salt bath containing cationic component of Li, Na and K and anionic components of CNO−and CO32−, where hydroxide compound selected from lithium hydroxide, sodium hydroxide and potassium hydroxide are added to the salt bath. Materials being in a hydrated state or in a free water containing state can be used for preparation or replenishing of the salt bath. An moistend air of (1×10−2 kg·H2O)/(1 kg dry air) can be used for mixing the salt bath. Containing ratio of Li, Na, K is preferable where a solidifying temperature of the mixture of carbonates of Li, Na, K in that ratio is lower than 500° C.

Abstract: 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.

Abstract: 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.

Abstract: A titanium-containing metallic material having a high heat-resistant and abrasion resistant surface is produced by (A) cleaning a titanium-containing metallic material, (B) first plating the cleaned surface of the metallic material with Cu or Ni by a strike or flash plating method, (C) second plating the first plated surface of the Ti-containing material with Ni, Ni-P alloy or a composite material comprising a Ni-P alloy matrix and fine ceramic particles dispersed in the matrix by an electroplating method, (D) non-oxidatively heat treating the second plated Ti-containing material at 450.degree. C.