[Effect of SiO2-ZrO2slurry coating on surface performance of zirconia ceramic].

ABSTRACT

OBJECTIVE: To evaluate the effect of SiO2-ZrO2slurry coating on surface performance of zirconia ceramic. METHODS: Seventy pre-sintered zirconia discs were randomly divided into seven groups with 10 discs per group. Sample discs in each group received one of the following seven different surface treatments, namely, sintered (group AS), sand blasting after sintered (group SB), coated with slurry of mole ratio of SiO2to ZrO221 (group 2SiO2-1ZrO2), coated with slurry of mole ratio of SiO2to ZrO211 (group 1SiO2-1ZrO2), coated with slurry of mole ratio of SiO2to ZrO212 (group 1SiO2-2ZrO2), coated with slurry of mole ratio of SiO2to ZrO213 (group 1SiO2-3ZrO2), coated with slurry of mole ratio of SiO2to ZrO214 (group 1SiO2-4ZrO2). Profilometer, X-ray diffractometer (XRD), energy dispersive spectrometer, scanning electron microscopy (SEM) were used to analyze surface performance. RESULTS: The surface roughness of the discs in group AS was lower than those in the other groups [(0.33 ± 0.03) µm] (P < 0.05), there was no statistically significant difference (P > 0.05) among group 2SiO2-1ZrO2[(3.85 ± 0.38) µm], group 1SiO2-1ZrO2[(3.78 ± 0.56) µm] and group 1SiO2-2ZrO2[(4.06 ± 0.48) µm], and no difference (P > 0.05) was observed between group 1SiO2-3ZrO2[(1.02 ± 0.09) µm] and group 1SiO2-4ZrO2[(1.53 ± 0.23) µm] either. However, surface roughness in all coating groups was higher than those in group SB [(0.86 ± 0.05) µm] (P < 0.05). According to the XRD pattern, group AS and all coating groups consisted of 100% tetragonal airconia and monoclinic zirconia was detected at surface of group SB. Contents of surface silicon of coating groups increased significantly, however, no silicon was detected at sample surface of group AS and group SB. SEM showed that zirconia grains of coating exposed since part of silicon was etched by hydrofluoric acid, a three-dimensional network of intergrain nano-spaces was created. CONCLUSIONS: SiO2-ZrO2slurry coating could make surface of zirconia rough and increase Si content without creating monoclinic zirconia.