| 摘要 |
PCT No. PCT/JP96/02912 Sec. 371 Date Jun. 2, 1997 Sec. 102(e) Date Jun. 2, 1997 PCT Filed Oct. 2, 1996 PCT Pub. No. WO97/13002 PCT Pub. Date Apr. 10, 1997This invention aims to provide a nitriding method of forming a relatively thick nitride layer on the surface of an aluminum material containing silicon, and an auxiliary agent for nitriding. By using a nitriding auxiliary agent mainly comprising aluminum containing a metal such as lithium or boron, which has a high bonding strength with oxygen, coexists with silicon to form substantially no silicide, or a nitriding auxiliary agent mainly comprising an Al-Mg-Cu alloy or an Mg-Zn-Cu alloy, heat treatment is applied by nitrogen gas with the aluminum material to be nitrided contacted with the nitriding auxiliary agent. Hence, a thick nitride layer can be easily formed even on the surface of an aluminum material containing silicon, and this is most suitable to surface nitride aluminum-silicon alloys, which possess superior castability.
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