Abstract: This invention relates to a method of anodising magnesium material. The method includes anodising the magnesium material whilst it is immersed in an aqueous electrolyte solution having a pH above 9, and in the presence of a phosphate. The phosphate is preferably an ortho-phosphate, and the solution also preferably includes a buffering agent such as tetra-borate to maintain the pH of the solution above 9. There are also described method steps prior to anodising. One step describes a cathodic cleaning of the magnesium material, prior to it being anodised. Another step describes a pre-treatment which preferably includes one or more substeps, namely a cleaning step and/or an etching step and/or a surface activation step.

Abstract: This invention provides a method for the anodization of magnesium or magnesium based alloys using an electrolytic solution containing ammonia, amines or both. The use of such an aqueous electrolytic solution in at least preferred forms alters the conditions under which anodization can occur to provide a more than satisfactory coating on the magnesium material with reduced cycle times.