CHEMICAL CONVERSION FILM ON AZ31 MAGNESIUM ALLOY AND ITS CORROSION RESISTANCE

The surface treatment process for AZ31 magnesium alloy using phosphate is investigated.Influence of factors such as pretreatment and process conditions on the quality of chemical conversion film is analyzed.The conversion process and anticorrosion behavior of the alloy are examined by electrochemical means.The surface morphology and composition of the conversion film are observed and analyzed respectively by EPMA.Results show that the chemical conversion film obtained by optimum process is uniform and compact with good protectiveness to the substrate of the magnesium alloy.