Corrosion Investigation of Stir Cast Zn-27Al Based Hybrid Composites Reinforced with Quarry Dust and Silicon Carbide Particles

Abstract

This paper investigates the corrosion behaviour of Zn-27Al based hybrid composites reinforced with quarry dust (QD) and silicon carbide particles (SiCp). The Zn-27Al hybrid composites containing 8 wt% and 10 wt% SiCp-QD particles reinforcement with varied weight percentage of 0, 25, 50, 75 and 100% quarry dust respectively were synthesized using stir casting technique. The corrosion behaviour of the composites was investigated in 0.3M H2SO4 and 3.5 wt% NaCl solution at 25oC using electrochemical methods in accordance with ASTM G59-97(2014) standard. The results show that for 8 wt% reinforcement, the hybrid composites A2 and A3 (corresponding to 50% SiCp: 50% QD and 25% SiCp: 75% QD respectively) having corrosion rate of 0.006 mmpy displayed superior corrosion resistance. For 10 wt% reinforcement, hybrid grades B1 (75% SiCp: 25% QD), B2 (50% SiCp: 50% QD) and B3 (25% SiCp: 75% QD) has superior corrosion rate of 0.0172, 0.0126 and 0.0135 mmpy respectively while B4 (corresponding to 100% QD) shows the most superior corrosion rate of 0.00315 mmpy when compared with the monolithic alloy having corrosion rate of 0.213 mmpy all in marine environment (3.5 wt% NaCl solution). However, except for composite grade A2 with 0.055 mmpy corrosion rate and B4 (corresponding to 100% QD) with superior corrosion rate of 0.0143 mmpy in 0.3M H2SO4 medium, all other composite grades performed poorly in the acidic medium.