The Research Of Synthesis Preparation Ultrafine Carbonization Niobium Particles By Mechanical Alloying Method

This paper studies the feasibility of preparation superfine carbonization niobium powder materials, using mechanical alloying method (also called high-energy ball milling method) and using niobium-based powder and graphite powder as raw materials. It systematically analyses the influence law of the main ball milling process parameters on the ball milling process and ball milling products. It puts forward the technical ways of adjusting carbonization niobium powder materials density and carries out reducing carbonization niobium powder materials density by adding carbonization vanadium powder, using the high-energy ball milling method. It explores a method of metal powder coated, by adding metal powder to the carbonization niobium powder and also using the above method.The research results indicate that mechanical alloying method can be used for synthesizing ultrafine NbC powder. Process parameters: niobium-based powder and graphite powder as raw materials, ball powder ratio 30:1, ball-milling speed 300r/min and milling time 20 hours. Process parameters are key to mechanical alloying method during ball-milling process. If the quality of process control agent—graphite is 1.5% of powder, the time of synthetic preparation carbonization niobium will shorten 10 hours. Process control agent makes particle size distribution more uniform in the experiments of synthetic preparation carbonization niobium particle. The ball milling results are better when filling rate is 0.5. X-ray diffraction analysis results show that carbonization niobium is formed by C atoms to Nb crystals in diffusion-solution during ball-milling process. The formation of NbC is gradual with an increase in milling time. The JADE software analysis shows that the intermediate products of synthesizing ultrafine NbC powder, in order Nb2C, among Nb4C3, Nb6C5, and finally getting NbC. The mechanisms of synthetic preparation NbC are diffusion mechanism and solid solution mechanism. The density of ball milling NbC and VC powder mixture is smaller than of NbC. This method can be used for adjusting density of NbC. With the increase of joining VC powder proportion, the density of (Nb,V)C composite carbide powder decreases. The way of ball milling carbonization niobium and metal powder can not make metal powder coat on the surface of NbC powder.