Synthesis of ZrO2 nanoparticle by combination of sol-gel auto-combustion method- irradiation technique, and preparation of Al-ZrO2 metal matrix composites

Abstract

Nanocrystalline ZrO₂ with particle size of about 38 nm was directly synthesized by sol-gel auto-combustion method. The overall process involved three steps: formation of homogeneous sol at 50-55°C; formation of dried gel at 110°C, and combustion of the dried gel at 400°C. Experiments revealed that ZrO₂ dried gel derived from glycine (Fuel) and nitrate sol exhibited self propagating combustion at 400°C that it was ignited in air. The auto-combustion was considered as a heat-induced exothermic oxidation-reduction reaction between nitrate ions and carboxyl group. After auto-combustion, products were calcined at 650°C. ZrO₂ nano particle were incorporated into the A356 aluminum alloy by a mechanical stirred at 850°C and after that, cylindrical specimens were cast. After preparing the samples, mechanical properties were measured. The results of microstructure, compression and hardness tests indicated that addition of ZrO₂ nano particulates to aluminum matrix composites improved the mechanical properties. Also, Based on experiments, it was revealed that the presence of ZrO₂ reinforcement led to significant improvement in hardness and compressive strength.