Experimental Study On Preparation Of NbC And TiC Powders By Vacuum Carbothermal Reduction

Titanium carbide and niobium carbide are used as ceramic materials for their high temperature resistance,wear resistance and high conductivity.Because of good corrosion resistance and very high hardness and used as a mechanical tool materials;It is used in heat-resisting alloy because of its excellent heat-resisting property.Whether in the basic industry,chemical industry or in the high-end aviation,defense technology has a very important application.Titanium carbide is a kind of important inorganic non-metallic materials and typical excess metal carbides,its crystal structure includes micro ionic bond,metallic bond and covalent bond,and NaCl crystal with the same three-dimensional structure,face-centered cubic crystal system structure,so it has high melting point?3140±90??,modulus of elasticity,hardness,low density(4.93 g·cm^-3),good corrosion resistance and excellent conductivity,thermal conductivity performance advantages,such as.Titanium carbide is the most widely used material among many excessive metal carbides.It is mainly used as raw material for the manufacture of TiC based ceramics and TiC foundation ceramics and composites.As a reinforcing agent or wear-resisting agent,it can be used to manufacture various metal-based ceramics and metal-based composites.As a high-temperature healing agent,it is used to prepare alumina ceramic matrix composites and as an anti-wear agent to prepare wear-resistant coatings.Its applications involve many fields such as mechanical processing,surface engineering,powder metallurgy and electronics industry.Niobium carbide?NbC?and titanium carbide?TiC?has the same structure,is a cubic crystal structure,and titanium carbide difference is its green metallic luster,sodium chloride type of cubic crystal system structure,high melting point,its melting point is3600?or so,high hardness,its hardness is 1800 HV,the advantages of good wear resistance,chemical stability,in addition the density and the density of steel material is very close to the density(7.78 g·cm^-3),the excellent performance is used as the ideal steel reinforced phase in the project,Therefore,it is widely used in technical fields such as ceramic metal,casting infiltration of metal materials,surface spraying of various materials.This article is based on baiyun obo ore,was studied using vacuum carbon thermal reduction method,useful ceramic matrix niobium carbide and the possibility of titanium carbide,the basic theory,the experiment with pigment grade TiO₂,Nb₂O₅,activated carbon powder as raw materials,which were studied by orthogonal experiment method several substances mixed vacuum carbon thermal reduction preparation of micro titanium carbide,niobium carbide mixture powder.By comparing the vacuum reduction of activated carbon powder with niobium pentoxide?Nb₂O₅?and titanium dioxide?TiO₂?,as well as the mixing of Nb₂O₅,TiO₂ and activated carbon powder under different molar ratio,different mixing ball grinding time,different reduction temperature and reduction time,experimental research on vacuum carbon thermal reduction was conducted.By means of laser particle size analyzer,tga,X-ray diffractometer and scanning electron microscope,the materials before and after reduction were tested and analyzed.The emphasis of this experiment is to prepare niobium carbide and titanium carbide products by mixed reduction,and then study the ferro-titanium carbide niobium carbide metal ceramics with excellent properties.This experiment mainly carries on the detailed calculation and detection to the mixed reduction experiment.The results show that the reaction temperature has the greatest influence on the reduction,followed by the carbon ratio and reaction time.Moreover,when the vacuum degree is 50-80 pa and the reduction temperature is 1600?,the average reduction degree can reach 92.6%.9 combination?ball mill 10 h,molar ratio of Nb₂O₅:TiO₂:C=1:3:20,insulation 1 h?as the best conditions,weightlessness rate is highest,the highest degree,and most of the nanoscale titanium carbide,niobium carbide powder,and the orthogonal experiment introduced the optimal factor combination,has carried on the experimental study of exploration,comparing with orthogonal experiment results the best 9 groups.Except for the reduction time,the other reaction conditions are the same,and the range of influencing factors of the reduction time is the smallest,which has little influence on the results.Therefore,the experimental reproducibility of these two groups is better.Combined with the experiment,the general rule can be preliminarily inferred:the temperature increases,the reduction degree increases;The ball grinding time was prolonged and the reduction degree was improved.The reduction degree was slightly improved by prolonging the reaction time.Moreover,by increasing the molar ratio of TiO₂,the reduction degree was improved,and it was concluded that mixed oxides were easier to complete the reduction reaction under different proportions of TiO₂ and TiO₂,and the specific mechanism needed further exploration.By comparing the preparation of NbC with mixed reduction and carbon-thermal reduction of Nb₂O₅,it was obviously found that,in particular,the reduction conditions of Nb₂O₅,reduction temperature and reaction time were reduced.