Study on the sintering properties of Mo–La₂O₃ nano-powders prepared by solution combustion method

Molybdenum (Mo) precursor powders doped by lanthanum oxides (La₂O₃) were prepared by the ultra-rapid solution combustion synthesis method using the low-cost and non-toxic starting materials, and the precursor powders were reduced and sintered. The effect of La₂O₃ doping content (mass fraction) on the properties of Mo–La₂O₃ alloys was studied. The results show that, the La₂O₃ doped molybdenum powders with the average particle size of 100~220 nm are obtained by the reduction of the combustion precursor in the hydrogen atmosphere at 700 ℃. The relative density of La₂O₃ doped molybdenum alloys sintered at 1600 ℃ is over 95%. With the increase of La₂O₃ doping content (mass fraction in the range of 0~1.0%), the microhardness increases firstly and then decreases. When the La₂O₃ doping content is 0.7%, the grain size of Mo is about 500 nm, and the microhardness of the materials reaches the highest as HV_0.2 564.