Evaluation of the Structure, Microhardness and Corrosion Properties of Cobalt-chromium Dental Alloys with Two Different Cooling Media

Abstract

This study investigates the impact of cooling rate after heat treatment on the electrochemical and microstructural properties of three dental Co-Cr alloys. Advanced techniques, such as scanning electronspectroscopy and X-ray diffraction,were used to evaluate the microstructures and compositions of the alloys, revealing the influence of elements such as tungsten and niobium on their electrochemical behavior. The results have shown that the alloys with 5%Mo exhibited higher porosity than the alloy with Nb and W. High melting temperature due to the presence of Nb and W ensured a more homogeneous material and a slightly altered structure. For all alloys, heat-treated samples showed higher microhardness compared with casting samples. A passive behavior was observed for all the samples with the best stability at high potential for the alloy with the highest Cr content due to the formation of a protective Cr2O3 passive layer. Water-quenched samples showed high impedance values, demonstrating their effectiveness in corrosion resistance. The choice of cooling methods and alloy composition is crucial for improving corrosion resistance and mechanical properties of dental frameworks.