A Study on the Pretreatment of Direct Electroless Nickel Plating on Magnesium Alloys AZ91D

Yong Wei Song; Da Yong Shan; En Hou Han

doi:10.4028/www.scientific.net/MSF.488-489.835

Paper Titles

Phosphate Conversion Coating on Diecast AZ91D and Its Corrosion Resistance
p.819

Characterization of Wear and Corrosion Protective Coatings Formed on AZ91 Magnesium Alloy and SiCw/AZ91 Magnesium Matrix Composite by Microarc Oxidation
p.823

Compressive Behavior of Extruded SiCw/AZ91 at Temperatures close to and above the Solidus of the Matrix Alloy
p.827

Phosphoric Conversion Coating and Chromic Conversion Coating for Die-Cast Magnesium Alloy ZM5
p.831

A Study on the Pretreatment of Direct Electroless Nickel Plating on Magnesium Alloys AZ91D
p.835

Corrosion of New Wrought Magnesium Alloys
p.839

Effects of Alloying Elements on Mechanical Properties of Mg-Al Alloys
p.845

Effect of Strong Magnetic Field on the Discontinuous and Continuous Precipitation in AZ91 Mg Alloy
p.849

Dynamic Fracture Behavior of Magnesium Alloy under Biaxial Stress
p.853

HomeMaterials Science ForumMaterials Science Forum Vols. 488-489A Study on the Pretreatment of Direct Electroless...

A Study on the Pretreatment of Direct Electroless Nickel Plating on Magnesium Alloys AZ91D

Abstract:

Magnesium alloys are considered as “difficult to plate” metal. The pretreatment processes play a key role for plating. The pretreatments of alkaline cleaning, chromic acid etching and hydrofluoric acid activating were carried out and the microstructures investigated by SEM and EDAX in detail. The hydrofluoric acid activating time of 8 minutes was determined by Potential-Time curve. The experimental results showed that the alkaline cleaning moved the grease and oils off the substrate surface, but there was no apparent surface morphology change. The chromic acid etching was a very critical step, and the optimum etching time of 1 minute was chosen; the eutectic α was severely etched, and the chromic compounds were mainly formed on the surface. During the hydrofluoric acid activating, the white activating product of magnesium fluoride was preferentially generated on the β–phase, and obvious morphology change has been observed on the alloy substrate surface.