Corrosion Behavior of Electroless Ni-P/Ni-B Coating on Magnesium Alloy AZ91D in NaCl Environment

摘要

The Ni-P/Ni-B coating was deposited on AZ91D magnesium alloy by electroless plating. Ni-P coatingas inner layer and Ni-B coating as outer layer. A tight and compact Ni-P/Ni-B coating on Mg alloysubstrate was formed via Ni-P plating for 70 min and Ni-B plating for 20 min. The corrosion behaviorof coating was studied by electrochemical test and neutral salt spray test in the presence of chlorideenvironment. The test results shown that the double coating has better corrosion resistance than singleNi-P or Ni-B coating. Ni-B plated outer layer functions as cathodic protective and sealing layer.