The study was carried out to determine the effect of human and animal urine on nitriding for improved mechanical properties of aluminium alloy material. The study adopted a 2×3 factorial design. The population comprised alloy materials that contain aluminium as elemental metal in its content. The specimens of 24 pieces of aluminium alloy materials were cut from 70mm diameter aluminium alloy machined to 50mm diameter. Human urine was obtained from urine houses built in Port Harcourt while animal urine was got from cattle butchers also in Port Harcourt. Twelve specimens were heated to a temperature of 5000C in a cylinder containing human urine for 4, 5, and 6 hours respectively while another 12 specimens were also heated to the same temperature in a cylinder containing animal urine for 4, 5 and 6 hours respectively. In either case, no quenching was applied, rather the materials were allowed to cool naturally. Direct testing and measurement of nitrided specimens were carried out using Brinell testing machine. The research question that guided the study was answered using mean while the null hypothesis was tested using Analysis of Covariance (ANCOVA) at 0.05 level of significance. It was found from the study that human and animal urine as local ammonia increased the hardness of aluminium alloy material. Animal urine is more effective than human urine on nitriding, nitriding time showed significant effect on hardness of aluminium alloy material.
