METHOD FOR IONIC-PLASMA TREATMENT OF CUTTING TOOL STEEL SURFACE Russian patent published in 2004 - IPC

FIELD: treatment of tool and part surfaces for imparting certain properties thereto.

SUBSTANCE: method involves, before treating tool surfaces, heating tool to temperature of 250-350⁰C and keeping said temperature at every stage of treatment process; providing ionic cleaning of surface at gas pressure below 0.01 Pa for 0.1-0.5 hour by creating electric arc discharge between emitting cathode and auxiliary anode, which results in formation of plasma in electrochemical gap; supplying negative voltage of 500-1,500 V to part under process, followed by treating of its surface with positively charged ions; supplying positive voltage to basic discharge anode; cutting-off from surface under treatment of metal ionic flux issued by electric arc discharge and simultaneously directing electron beam flow to basic discharge anode for exciting and maintaining in chamber of glow discharge; supplying negative voltage of 200-500 V onto tool under treatment process and providing nitriding for 0.5-2.0 hours at pressure 0.1-1.0 Pa of nitrogen or nitrogen-containing gas, with temperature of tool being maintained at constant level throughout the entire process or periodically changed within the range of 250-350⁰C, from higher value to lower value and vice versa, at cycle of 0.25 hour; after termination of nitride process, creating pressure below 0.0015 Pa in chamber; supplying negative voltage of 200-500 V to tool under treatment process; directing metal part of discharge plasma onto surface under treatment process and providing ionic-plasma spraying of metal nitride from emitting cathode to obtain 0.5-2.0 micron thick layer. Thickness ratio of nitrided layer to layer obtained by spraying of nitride from emitting cathode is at least 5:1.

EFFECT: increased strength and wear-resistance of treated part or tool.

5 cl, 1 dwg, 1 tbl, 1 ex