To solve the following problems with a conventional surface treatment method for an iron alloy material: the diffused amount of diffusing elements serving as a diffusing agent is not sufficient and also a treatment agent has a short life, and therefore a treatment bath may change with time to cause a variation in forming a hardened layer.
In the surface treatment method, after performing a pre-nitriding treatment on a surface of the iron alloy material (material to be treated), a diffusion treatment is performed to form a surface hardened layer. After performing a nitriding treatment on the surface of the iron alloy material, actually nitrided material to be treated is heated and retained in 400-700 °C molten salt, thereby forming the surface hardened layer consisting of a nitride or a carbonitride of one or more types of elements such as a group 4-7 element in the fourth to sixth period in the periodic table on the material to be treated.
TAKAHASHI KATSUHIRO
| JP2000178711A | 2000-06-27 | |||
| JPS6240362A | 1987-02-21 | |||
| JPS6270561A | 1987-04-01 | |||
| JP2008189988A | 2008-08-21 | |||
| JPH03202460A | 1991-09-04 |
Michiko Ema
Chiori Ueda
Takaya Muramatsu
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