Alumina catalyst waste utilization for aluminum-based composites using the friction stir process

A significant amount of environmental pollution is caused by oil refinery industries in the form of spent alumina catalyst (SAC) waste generated during the process. This waste causes various detrimental effects on human health. In this study, an effort has been made to consume the SAC in the fabrication of aluminum-based composite materials via the friction stir process (FSP). An X-ray diffraction image of the SAC powder used in this work confirms the occurrence of Al2O3, Fe2O3, SiO2, and CaO phases. These hard-phase materials form the basis for SAC to be used as reinforcement content with the aluminum alloy. The FSP is used to create the composite material. It is evident from the scanning electron microscopy image of the Al/SAC composite developed by the FSP technique that fair distribution of constituent ingredients is attained during the process. The incorporation of SAC contents in the aluminum alloy results in remarkable enlargement in tensile strength and hardness of the composite material. The Al2O3, Fe2O3, SiO2, and CaO phases of SAC showed a considerable effect on thermal expansion and corrosion weight loss of the composite.