An interfacial study of sol–gel-derived magnesium apatite coatings on Ti6Al4V substrates

Magnesium apatite coatings on Ti6Al4V substrate were synthesized by the sol–gel dip-coating method. Magnesium was incorporated in the coating according to the formula (Ca10−xMgx)(PO4)6(OH)2, where x = 0, 0.50, 1.00, 1.50 and 2.00. Approximately 2-μm-thick apatite coatings were derived after five cycles of dip–drawing–drying–firing process. A transitional region (Rt) was formed between substrate and coating during the firing process. Adhesion tests show that the adhesion strength between substrate and apatite coating is enhanced by the incorporation of magnesium in the coating. The quantity of magnesium incorporated appeared to correspond to the Mg–Ti–O chemical bonds formed in the transitional region, which contributed to the adhesion strength of the coatings.