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 tech- niques, such as scanning electronspectroscopy and X-ray diffraction,were used to evaluate the microstructures and compositions of the alloys, revealing the influence of ele-ments such as tungsten and niobium on their electro-chemical 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 Cr 2 O3 passive layer. Water-quenched samples showed high impedance values, demonstrating their effec-tiveness in corrosion resistance. The choice of cooling methods and alloy composition is crucial for improving corrosion resistance and mechanical properties of dental frameworks