Experimental Study On Self–propagating Preparation Of Ferrochrome Nitride

Ferrochrome nitride,as additive,mainly used for the production of special steel containing nitrogen. Nitrogen can make the steel has high strength and high corrosion resistance, and can keep the plasticity of the steel in good level. Nitrogen contributes to the formation of austenite, it expands austenite region is about 30 times that of nickel. When produces the nickel chromium and chromium manganese austenitic stainless steel, nitrogen as component can partly replace the shortage of nickel, produces low nickel stainless steel can bring great economic benefits. In this thesis, the preparation of ferrochrome nitride by self-propagating, and making full use self-propagating reaction process equipment is simple, time is short, energy conservation, environmental protection, and high product purity. Since self-propagating reaction was evoked, it can keep self-sustaining reacting, can be obtained the products which meet the requirements of structure and composition. Therefore, the preparation of ferrochrome nitride by self-propagating is a new worthy method of further study.This thesis mainly consists of two parts, which are the theoretical calculation and experimental verification. The technological process: through the self-propagating reduction reaction between aluminum powder, chromium oxide and iron oxide has occurred, adding sodium nitrate as exothermic compound and urea as nitriding medium, can produce ferrochrome nitride with the nitrogen content of more than 3%.The part of thermodynamic calculation: through the thermodynamic calculation of the self- propagating reaction between aluminum powder, chromium oxide and iron oxide can know that self-propagating reaction of this experiment can be carried out self-sustaining reaction. Through calculated the amount of sodium nitrate, can obtain the addition amount of sodium nitrate which as exothermic compound. Adding sodium nitrate can keep the reaction system with sufficient heat. Contributes to make full of reacting, To ensure better separation of impurities and ferrochrome nitride.The part of experimental verification: first of all, using self-propagating to prepare ferrochrome alloy, the purpose of this experiment is verified the exothermic compound to the effect of self-propagating. Then by using urea as nitriding medium for preparation of ferrochrome nitride. The results show that the self–propagating preparation ferrochrome nitride is feasible. Test analysis of ferrochrome nitride, the ferrochrome nitride mainly exists Cr-Fe, CrN, Cr2 N, Fe4 N etc; Chromium content is over 60%, nitrogen element content is over 3%; the contents of other impurities were controlled at 1%.The addition of urea will not affect the self-propagating reaction.The thesis study method compared with the existing methods for the preparation of ferrochrome nitride, it has obvious advantages. In this thesis, using mature self-propagating technology to prepare ferrochrome nitride, select urea as nitriding medium, can be obtained the ferrochrome nitride which meet industrial production standards. Due to this method has the advantages of its simple process, short process and low requirements for the atmosphere environment, it can meet the requirements of high production and low cost on industrial production.