Synthesis and characterisation of chromium, eggshell and grinding sludge-reinforced aluminium metal matrix composite: an experimental approach

This investigation deals with the utilisation of industrial waste to develop an aluminium (Al)-based composite. Waste eggshell (ES) generated from the food industry has been used as the primary reinforcement material. Waste grinding sludge (GS) produced from the iron-forging sector was utilised as the secondary reinforcement content. Chromium (Cr) was also added to the composite material to prevent the composite material’s grain growth. The composite material was developed by the stir casting process. Experimental results concluded that the tensile strength, compressive strength and hardness of the base material (AA 5052 alloy) had been improved by about 18.02, 23.40 and 49.53%, respectively, by adding 4.5% of ES, 4.5% of GS and 1.5% of chromium. The microstructural analysis of the AA 5052/4.5% ES/4.5% GS/1.5% chromium composite shows the fair distribution of reinforcement content. The X-ray diffraction of the aluminium/4.5% ES/4.5% GS/1.5% chromium composite shows the occurrence of aluminium, ferric oxide (Fe₂O₃), calcium carbonate (CaCO₃), calcium oxide (CaO) and chromium phases. The weight loss due to corrosion and thermal expansion behaviour of the developed composite have also been explored to observe the effect of ES, GS and chromium addition on the aluminium alloy.