Hydroxyapatite ceramics coating on magnesium alloy via a double layered capsule hydrothermal hot-pressing

Abstract

Hydroxyapatite (HA: Ca₁₀(PO₄)₆(OH)₂) ceramic coating on magnesium (Mg) alloy (AZ31; Mg–3Al–1Zn) was achieved simultaneously by using a double layered capsule hydrothermal hot-pressing (DC-HHP) method at the low temperature as low as 150°C with no special surface treatment on the surface of the Mg alloy. A mixture of calcium hydrogen phosphate dehydrate (DCPD) and calcium hydroxide (Ca(OH)₂) was used as a starting powder material for solidifying HA. Pull-out tests were conducted in order to obtain an estimate of adhesive properties for the HA coating to the Mg alloy. Average value of maximum shear stress was determined to 6.1 ± 1.0 MPa. After the pull-out fracture tests, it was revealed that HA ceramics remained on the surface of the Mg alloy. The Mg alloy could be bonded to HA ceramics with good adhesive properties.