Hydroxyapatite Effect on the Corrosion Rate of AMC Al-Zn by Powder Metallurgy

Abstract

Al-Zn-based AMC is a light metal, with low density, excellent mechanical and mechanical properties, suitable for use in automotive, electrical, general-purpose electronics, machinery and equipment. However, the development of this alloy is limited by its low hardness and low corrosion resistance, which limits its use in many applications. This corrosion process can cause fitting corrosion and can damage the passive oxide layer that protects the metal from corrosion. This study aimed to increase the corrosion resistance of AMC Al-Zn by adding hydroxyapatite ceramic reinforcement from snail shells in a corrosive medium of 3.5% NaCl solution. The HAp is used as an AMC amplifier. AMC uses Al-Zn alloys with a ratio of 90% to 10% by mass. The variation of HAp enhancer used was 10, 15, 20, 30 and 40% by weight. This AMC was produced by powder metallurgy using 250 KPa compression for 20 min with sintering at 550°C for 2 h followed by slow cooling. The characterization of Al-Zn-based AMCs was performed by electrodynamic polarization testing in 3.5% NaCl solution. From the experimental results, the addition of HAp snail waste at a concentration of 20% by weight with matrix composition Al90-Zn10 is an AMC preparation with optimal corrosion resistance. The corrosion rate of Al90-Zn10/20HAp is 0.01 mmpy, while the corrosion rate of Al90-Zn10/0HAp is 1.15 mmpy. The addition of HAp up to 20% by weight showed the highest micro-hardness (117.90 Hv) while the smallest micro-hardness occurred at AMC Al90-Zn10/0HAp (87.57 Hv). The HAp material could very well be used as an AMC-reinforced biomaterial for biomedical applications.