Fundamental Study On Preparing Vanadium Nitride And Carbide By Carbothermal Reduction And Nitridation Of V₂O₃

Vanadium nitride and carbide, as a solid solution, is an important additive to steel. The main reason that eighty to ninety percent vanadium is used in iron and steel industry is that vanadium may be translated into vanadium nitrides or carbides with nitrogen or carbon. These compounds can result in sedimentation and rigidification in the structure of steel. They can also fine fabric of crystalloid. So they will play a more important role in the current time. Various kinds of steel such as structure steel, tool steel, pipe line steel, reinforcing steel bar, common engineering steel and cast iron may be improved in their properties by vanadium nitrides and carbides. They can improve iron or steel general mechanical performance i.e. anti-polish, anti-rust ability, toughness, intensity, tractility, rigidity and anti-fatigue performance. In addition, they can promote the welding ability of steel because they can remove the impurity between the gaps especially in high-intensity steel.Comparing with VC, VN can make better effect on the rigidification in the structure of steel and fining fabric of crystalloid with less addition and lower cost. In order to increase the amounts of vanadium and nitrogen, a only efficient way is to add VCN with high amounts of nitrogen directly in iron and steel.How to produce VCN with enough nitrogen economically and effectively and how to analysis thermodynamics and dynamics are main objects studied in the thesis.Vanadium nitride and carbide was prepared by heating a mixture of V₂O₃ and carbon powder under a flowing nitrogen atmosphere under normal pressure. The sample was put in a reactor made in graphic and designed like a goblet for the experiments.While V₂O₃ is reduced into VC, VC is nitrided into VN by N₂. It means the reduction and nitrification reaction happen synchronously. V₂O₃ is reduced into VC prior to VO. So some study on thermodynamics based on VO initiatively is not proper. The translated temperature in reducing and nitriding reaction is affected by the gas pressure. If C is...