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 metal member is produced with enhanced corrosion resistance by salt bath nitriding. Specifically, in a nitriding salt bath containing Li+, Na+ and K+ ions as cation components and CNO? and CO3?? ions as anion components and enhanced in oxidizing power by addition of an oxidizing-power-enhancing substance selected from the group consisting of alkali metal hydroxides, bound water, free water and moist air, the metal member is immersed such that an nitrided layer is formed on a surface of the metal member and concurrently, an oxide film is formed on an outermost layer of the nitrided layer. As a subsequent step to the immersion in the nitriding salt bath, the metal member is immersed in a displacement cleansing salt bath which contains an alkali metal nitrate.

Abstract: An automobile chassis member includes a lithium-iron composite oxide layer as its outermost surface and a surface-modifying layer formed immediately below the lithium-iron composite oxide layer. The surface modifying layer contains as a surface-modifying diffusion element at least nitrogen element bonded with another element in a base material of the automobile chassis member or diffused in the base material. The lithium-iron composite oxide layer is deposited in an amount of from 10 to 1,500 mg/m2 in terms of lithium atoms.

Abstract: A metal member is produced with enhanced corrosion resistance by salt bath nitriding. Specifically, in a nitriding salt bath containing Li+, Na+ and K+ ions as cation components and CNO− and CO3−− ions as anion components and enhanced in oxidizing power by addition of an oxidizing-power-enhancing substance selected from the group consisting of alkali metal hydroxides, bound water, free water and moist air, the metal member is immersed such that an nitrided layer is formed on a surface of the metal member and concurrently, an oxide film is formed on an outermost layer of the nitrided layer. As a subsequent step to the immersion in the nitriding salt bath, the metal member is immersed in a displacement cleansing salt bath which contains an alkali metal nitrate.

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.