Preparation of Al2O3/Cu porous composites by the combination of solution combustion synthesis and powder metallurgy method

Al2O3/Cu composite powder was prepared by solution combustion synthesis and hydrogen reduction method using copper nitrate, aluminum nitrate, glucose and urea as raw materials. The Al2O3/Cu composite powder was uniformly mixed with the pore-forming agent sodium chloride, and then the mixed powder was cold-pressed. Finally, the Al2O3/Cu porous composite material (A-C-M) was prepared by sintering-dissolution process. The microstructure of powder raw materials and A-C-M were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The compression performance of A-C-M was tested by universal testing machine. The effect of glucose addition on the combustion product powder was studied. The effect of Al2O3 content on the compression performance of A-C-M was discussed. The results show that when the molar ratio of glucose to Cu(NO3)2 is 1, the specific surface area of the combustion product reaches a maximum of 12.5 m2·g-1. After the combustion product is calcined to remove carbon, the pores of the powder particles increase, but the specific surface area is reduced to 10.2 m2·g-1 due to the sintering effect of high temperature calcination. After the calcination product was reduced by hydrogen, the powder particles were broken into floccules. However, due to the sintering effect of high reduction temperature, the specific surface area of the obtained Al2O3/Cu composite powder was further reduced to 7.5 m2·g-1. With the increase of Al2O3 content, the porosity of A-C-M increases gradually, and its compressive strength decreases gradually.