An investigation of corrosive effects on zirconia with different crystal structures

This study aimed to compare the time-related corrosive resistance in different corrosive solution environments after sintering of zirconia with different crystal structures. The zirconia samples were produced in pellet form as 12.7 × 3 mm. To determine the time-related corrosion resistance of the sintered samples in sodium carbonate (Na₂ CO₃ ), sodium chloride (NaCl), and citric acid (C₆ H₈ O₇ ) solutions, the weights were measured at baseline then on the first and fifth days and the microhardness values were calculated. For the evaluation of surface appearance, images were obtained with a scanning electron microscope. The baseline microhardness values of the groups with 3 and 10 mol% yttria-stabilized zirconia samples were found to be 1,064 VHN and 1,079 VHN, respectively. The microhardness values of the groups with 3 mol% yttria-stabilized zirconia samples immersed in Na₂ CO₃ 1d (1,010 VHN) and 5d (1,060 VHN), and NaCl (1d (1,010 VHN) and 5d (1,055 VHN) were found to be affected more. The microhardness values of the sample group (1,064 VHN) with 10 mol% yttria doped zirconia which was left for 5 days in citric acid were found to be lower than the sample group (1,120 VHN) with 3 mol% yttria added. C₆ H₈ O₇ was seen to have a greater corrosive effect with increased yttria content and the microhardness value decreased. With longer duration of the samples of all the groups in C₆ H₈ O₇ , NaCl, and Na₂ CO₃ solutions, the surface characteristics of the samples were affected negatively. With prolonged immersion in the corrosive solutions, the resistance to the corrosion causing the changes in the surface topography of the samples was seen to decrease.