OPTIMIZATION OF COMPACTING PRESSURE AND SINTERING TIME FOR DENSIFICATION AND MICROHARDNESS OF A CO-28%CR-6%W (STELLITE-TYPE) BIOMEDICAL PRODUCED BY POWDER METALLURGY
Keywords:
Biomaterial, Co-Cr-W alloys, Powder metallurgy, Compaction, Vacuum sintering, MicrohardnessAbstract
In modern history, metals have been used as implants for more than 100 years ago. In the early development, metal implants faced corrosion and insufficient strength problems.
Cobalt–chromium-based alloys are widely used in dental and orthopedic implants due to their high corrosion resistance, wear resistance, and biocompatibility[1,2].
This study investigates the influence of compaction pressure and sintering time on the densification and mechanical properties of Co–28Cr–6W (called Stellite) alloys for biomedical applications.
Cylindrical specimens were produced by uniaxial pressing at loads ranging from 30 to 140 kN, followed by vacuum sintering at 1000 °C for durations between 30 and 600 minutes.
Microstructural observations, densification measurements, and Vickers microhardness testing were performed to evaluate the effect of processing parameters. Results show that both higher compaction pressure and longer sintering time significantly enhance densification, with relative densities increasing from approximately 65% to over 90% of the theoretical value. Correspondingly, microhardness values improved consistently, reflecting enhanced bonding and reduced porosity.
These findings demonstrate the feasibility of producing high-density Co–Cr–W components with tailored properties for dental and orthopedic implants through controlled powder metallurgy processing. The results contribute to the understanding of sintering kinetics in Co–Cr-based alloys and their optimization for biomedical performance.
