Patent ID: 8840739
Filing Date: 2014-09-23
Classification: C22C,C22F

Abstract:
1. A method of producing a magnesium-based alloy surface layer on a surface of a magnesium alloy article to improve the resistance of the magnesium alloy surface to corrosion from contact with water, the method comprising: traversing the surface of the article to be protected with a surface of a tool, by movement of the tool or of the article, and applying cooling liquid at cryogenic temperature to the article surface as the article surface is being traversed by the tool, the tool surface being pressed against the cryogenically-cooled surface of the article in sliding frictional contact to compress and deform the surface layer, without cutting material from the surface layer, to a predetermined depth to change the metallurgical grain structure of the surface layer, the tool repeatedly traversing the cryogenically-cooled surface while progressively advancing into continued engagement with the cryogenically-cooled surface, the changed surface layer having greater resistance to corrosion than an untreated region of the magnesium-based alloy article.