EFFECT OF SURFACE-TREATMENT ON UNALLOYED TITANIUM IMPLANTS - SPECTROSCOPIC ANALYSES

Surgical implant finishing and sterilization procedures were investiga ted to determine surface characteristics of unalloyed titanium (Ti). A ll specimens initially were cleaned with phosphoric acid and divided i nto five groups for comparisons of different surface treatments (C = c leaned as above, no further treatment; CP = C and passivated in nitric acid; CPS = CP and dry-heat sterilized; CPSS = CPS and resterilized; CS = C and dry-heat sterilized). Auger (AES), X-ray photoelectron (XPS ), and Raman spectroscopic methods were used to examine surface compos itions. The surface oxides formed by all treatments primarily were TiO 2, with some Ti2O3 and possibly TiO. Significant concentrations of car bonaceous substances also were observed. The cleaning procedure alone resulted in residual phosphorus, primarily as phosphate groups along w ith some hydrogen phosphates. A higher percentage of physisorbed water appeared to be associated with the phosphorus. Passivation (with HNO3 ) alone removed phosphorus from the surface; specimens sterilized with out prior passivation showed the thickest oxide and phosphorus profile s, suggesting that passivation alters the oxide characteristics either directly by altering the oxide structure or indirectly by removing mo ieties that alter the oxide. Raman spectroscopy showed no crystalline order in the oxide. Carbon, oxygen, phosphorus, and nitrogen presence were found to correlate with previously determined surface energy. (C) 1998 John Wiley & Sons, Inc.