MICRODISSOLUTION OF CALCIUM-IONS FROM CALCIUM-ION-IMPLANTED TITANIUM

Microdissolution of calcium ions from calcium-ion-implanted titanium i nto nitric acid solutions (pH-0.99, 0, 1 and 2) and phosphate-citric a cid buffers (pH 5.2 and 7.2) at 310 K for 10(3)-5 x 10(6) s was charac terized using X-ray photo-electron spectroscopy. As a result, the surf ace oxides with calcium were found to dissolve in the solutions. Oxyge n decreased and titanium increased in the surface oxide according to t he dissolution. In addition, hydroxyl radicals decreased in number and the proportion of Ti4+ in titanium increased. Core-level binding ener gies of calcium, and titanium originating from Ti4+, decreased with th e dissolution. These changes were caused by the transformation of surf ace oxide according to the dissolution. Calcium dissolved and, consequ ently, the surface oxide became titanium oxide. It is feasible to esti mate the microdissolution of an element from materials using surface a nalysis techniques. Copyright (C) 1996 Elsevier Science Ltd