发明授权
- 专利标题: Chromium-silicon diffusion coating
- 专利标题(中): 铬 - 硅扩散涂层
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申请号: US962753申请日: 1997-11-03
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公开(公告)号: US5972429A公开(公告)日: 1999-10-26
- 发明人: George T. Bayer , Kim A. Wynns
- 申请人: George T. Bayer , Kim A. Wynns
- 申请人地址: PA Tarentum
- 专利权人: Alon, Inc.
- 当前专利权人: Alon, Inc.
- 当前专利权人地址: PA Tarentum
- 主分类号: C23C10/52
- IPC分类号: C23C10/52 ; C23C10/54 ; C23C16/22
摘要:
A method of diffusion coating a surface of an alloy product containing at least 5 wt. % iron with a chromium-silicon coating uses a dual activator containing a fluoride salt and a chloride salt, at least one of those salts particularly being ammonium chloride or another ammonium halide salt. The pack mix contain at least 20% chromium and a chromium to silicon ratio of at least 10 to 1. The workpiece is heated to at least 2050.degree. F. to obtain a coating of at least 10 mils which contains at least 30% chromium. Upon heating the ammonium salt will form a reducing environment containing molecular hydrogen. The presence of molecular hydrogen speeds up the chemical reactions by an additional reduction reaction to create the surface coating which enables the coating reactions to occur shorter hold times.