Selective laser melting dental CoCr alloy: microstructure, mechanical properties and corrosion resistance

Purpose In this paper, the mechanical properties and corrosion resistance of CoCr alloy fabricated by selective laser melting (SLM) were studied, and the changes of performance after porcelain sintering process were also analysed. This study is to point out the relationship between the microstructure, mechanical properties and corrosion resistance of CoCr alloys prepared by SLM after porcelain sintering process. In addition, the biosafety of the sintered CoCr alloy was evaluated. Design/methodology/approach The microscopic feature changes of CoCr alloy samples after porcelain sintering process were observed by DMI 5000 M inverted metallographic microscope and Nova Nano430 FE-SEM. Moreover, phase identification and determination were conducted by X-ray diffraction (XRD) using Smartlab X-ray diffractometer. The Vickers microhardness was measured on the HVS-30 microhardness tester, and tensile tests were carried out on a CM3505 electronic universal testing machine. The corrosion resistance was tested by a classical three-point electrode system electrochemical method, then the ion precipitation was measured by using an atomic absorption spectrometer of Z2000 7JQ8024. Findings The XRD results indicate that the transition of gamma phase (FCC) to e phase (HCP) occurs during the porcelain sintering processing of CoCr alloy. Moreover, the Vickers microhardness of the upper surface and the side surface of the CoCr alloy sample was improved by more than 36%. In addition, the ultimate strength of CoCr alloy via porcelain sintering treatment was increase to 1,395.3 +/- 53.0 MPa compared to 1,282.7 +/- 10.1 MPa of unprocessed CoCr alloy. However, the corrosion resistance of CoCr alloy samples decreases after porcelain sintering process. Originality/value There are few studies on the relationship of microstructure, mechanical properties and corrosion resistance of CoCr alloys prepared by SLM after porcelain sintering process. In this study, the microstructure, mechanical properties and corrosion resistance of CoCr alloy after porcelain sintering process were studied, and the biosafety of the alloy was evaluated. The research found that it is feasible to apply CoCr alloy fabricated by SLM to dental medicine after porcelain sintering process.