EFFECT OF CITRIC ACID CONTENT ON PROPERTIES OF ELECTROPLATED RE-Ni-W-P-SiC COATING

The effect of citric acid on properties of electroplated RE-Ni-W-P-SiC composite coating was studied.The most proper content of citric acid in the electrobath was determined.With the increase of citric acid content,the microhardness of the composite coating increased first and then decreased,and it reached the maximum value in 150g/L.The microstructure became smooth,crystal grains distributed uniformly and compactly,and the thickness was basically reduced.The most proper content of citric acid was 130-150g/L.