METHOD OF PRODUCING CHROME NITRIDE Russian patent published in 1994 - IPC

FIELD: metallurgy. SUBSTANCE: method comprises steps of pouring powder, containing (mass % ): chrome 97.0; silicium 0.2; aluminium 2.3; ferrum 0.44; carbon 0.02; sulfur 0.015; phosphorus 0.005; non-ferrous metal 0.02, and having fineness less, than 0.2 mm, into a crucible, placing the last to a reactor; approaching an electric helix to the powder, sealing the reactor and filling it by nitrogen till pressure 16 MPa; applying an electric current pulse to the helix with amplitude 5A and duration value 0.5 s. Maximum temperature of heating up, equal to 1500 C, corresponds to producing of stable chrome half - nitride Cr₂N. After cooling the sample till 1190 C a process of forming CrN begins. Heat quantity of such reaction allows to maintain temperature 1190-800 C over 30 min, the reaction takes place in a special mode. The product, had been produced, is a briquette with porosity degree 45% and compression strength 20 MPa. The briquette contains 21.2 mass % of nitrogen. EFFECT: enhanced density and strength of the product with high content of nitrogen and lowered loss of chrome and nitrogen at alloying. 1 cl, 3 tbl