Effects of surface treatment methods on the phase\rchanges in zirconia

Abstract

Aim: In this study, zirconia was subjected to various surface treatments,\rnamely, Al₂O₃ sandblasting, CoJet, and coating, the effects of these\rmethods were investigated with the use of SEM, EDX, and XRD. Coating of\rzirconia surface with silica using the ultrasonic spray method is performed\rfor the first time in this study. The present results are particularly\rimportant for the conduct of future studies.\rMethodology: Eighty-four zirconia samples were used for the XRD (n=28),\rSEM (n=28), and EDX (n=28) analyzes. Commercial semi-sintered discs\r(Kuraray-Noritake Katana HT10 14 mm, Japan) were used in this study. The\rsize of the zirconia samples (i.e., 6 mm in diameter and 3 mm in height)\rwas designed in a computer environment, factoring in the degree of\rshrinkage following sintering. The dimensions of the sintered samples were\rdetermined with a digital caliper. Four surface treatments were employed\rin this study.\rResults: The surfaces of the zirconium samples subjected to different\rsurface treatments were investigated. The SEM and EDX images of the\rtreated zirconia were taken at 80×, 250×, 1000×, 10,000×, and 20,000×\rmagnifications and then compared with those of the untreated sintered\rsamples. The XRD analysis results showed that the intensity of the peaks of\rthe zirconium oxide samples at the 2θ range of 20°–40° varied from the\rtetragonal phase to the monoclinic phase along the surface.\rConclusion: The sandblasting and CoJet surface treatments caused\rmechanical changes on the surface of the zirconia samples, and Al₂O₃\rparticles were detected on the surface, as shown by the SEM and EDX\ranalysis results. The XRD analysis results for the blasting group differed the\rmost from the results for the control group, by contrast, the results for the\rultrasonic spray group were nearly the same to those for the control group.