Preparation Of Refractory Metal Mo And Ru Powders

Refractory metals and alloys are very important metal materials,because of their excellent physical,chemical and mechanical properties.They are widely used in aerospace,defense industry,energy,metallurgy,chemical industry,nuclear industry,electronic information and other fields.The role of refractory metals and their alloys materials in some applications（space,aviation and defense）are irreplaceable,so the development of refractory metals fabrication is very important issue.With the rapid development of electronic and national defense in the 21 st century,the requirements of refractory metal materials have been increasingly improved.Refractory metals powders have great influence on the properties of refractory metals materials,and they even restrict the properties of refractory metals materials.Therefore,the preparation of high-performance refractory metals powders is of great importance to the fabrication of high-performance refractory metal materials.In this paper,micro-spherical Mo,Ru and W-Mo alloy particles were successfully synthesized by spraying dry combined with ignition.The thermal decomposition behavior of（NH₄）₂RuCl₆ pieces was investigated,which includes two stages.The first stage is decomposed from 255 ℃ to 314 ℃,and the products are NH3,HCl and（NH3）4Ru3Cl12.The second stage is from 314 ℃ to 360.9 ℃,N2 and HCl are revealed,and Ru is residual.The spraying dry process of（NH₄）₂RuCl₆ solution was investigated.The results show that the morphology,size and surface of（NH₄）₂RuCl₆ particles were controlled by the spray drying process.Both gas/liquid rate and drying temperature influence the morphology and size of spray dried particles,while solution concentration is directly proportional to size of spray dried particles.The ignited processing of spherical（NH4）6Mo7O24·4H2O particles to be spherical Mo particles was investigated.With the heating rate increasing,the phenomenon of fragmentation was reduced.While the heating rate was greater than 10℃/min,the phenomenon of fragmentation was disappeared and the Mo particles was spherical.On one hand,the heating rate was proportional to the particle size.On the other hand,the heating rate was inversely proportional to the specific surface area（BET）of the powder.Finally,micro-spherical Mo,Ru and W-Mo alloy particles were successfully synthesized by spraying dry combined with ignition.