Surface-conditioning agent, as well as magnesium member or magnesium alloy material with film, and manufacturing method therefor

Abstract

This invention provides a technique that enables a chemical conversion coating excellent in adhesiveness and corrosion resistance to be formed on or over a magnesium material or magnesium alloy material and use of the technique. The above object is achieved by performing a surface conditioning treatment by using a surface conditioning agent that includes specific dibasic calcium phosphate particles before performing a chemical conversion for forming the chemical conversion coating.

1 . A surface conditioning agent comprising particles of dibasic calcium phosphate, the particles of dibasic calcium phosphate having a D 50  of from 0.1 μm to 0.8 μm, and the dibasic calcium phosphate being monetite and/or brushite. 
     
     
         2 . A method for manufacturing a magnesium material or magnesium alloy material with a coating, the method comprising:
 a step of contacting a magnesium material or magnesium alloy material with the surface conditioning agent according to  claim 1 ; and   a step of contacting the magnesium material or magnesium alloy material that has been contacted with the surface conditioning agent with a surface treatment agent including a phosphate ion and a calcium ion.   
     
     
         3 . A magnesium material or magnesium alloy material with a coating, comprising a coating that includes crystalline particles of dibasic calcium phosphate and that is provided on or over a surface of a magnesium material or magnesium alloy material, the crystalline particles of dibasic calcium phosphate having an average particle size of from 0.7 μm to 25 μm and having a particle size distribution standard deviation of 5 or less, and the dibasic calcium phosphate being monetite and/or brushite.