Electrophoretic Deposition of Wollastonite on 316L Stainless Steel from Different Dispersing Media

Natural wollastonite was electrophoretically deposited on 316L stainless steel in order to promote a bioactive surface. The effect of the disperse media and the deposition time on the deposit weight and microstructure of the wollastonite coatings was evaluated. The disperse media were methanol, acetone, ethanol, propyl alcohol and the deposition time was in the range of 1 to 180 s. Suspensions were prepared by using wollastonite powder with a mean particle size of 2 μm at a concentration of 1 g/L. The deposition was performed under a DC field of 800 V. The coated substrates were sintered at temperatures ranging from 900 to 1050oC in air for 2 to 4 h. Dense, homogeneous and crack-free coatings were obtained by using methanol and acetone. No wollastonite coating was obtained by using ethanol at these processing conditions and few wollastonite particles were deposited on the metallic substrates by using propyl alcohol. The deposit weight increases as the deposition time is increased in all the cases.