Zinc-modified hydroxyapatite coatings obtained from parascholzite alkali conversion

Abstract In this study, a novel method of zinc-substituted hydroxyapatite coating is presented. The technique consists of a two-step hydrothermal process. In the first step, the coatings consisted of parascholzite (JCPDS-01-086-2372), a mixture of parascholzite and monetite (JCPDS-01-071-1759) or parascholzite and brushite (JCPDS-72-0713), depending on the Zn concentration in the precursor solution. The second step consisted of an alkali conversion in a KOH solution. The resulting coating was identified as zinc-doped hydroxyapatite. Growing amounts of ZnO were identified for the coatings obtained with higher Zn content. Rietveld refinement revealed a slight decrease in the unit cell volume, due to zinc partial substitution, when compared to pure hydroxyapatite coatings.