COAT FOR CUTTING TOOLS Russian patent published in 2003 - IPC

FIELD: application of coats on tool materials by means of arc discharge in atmosphere of chemically active gases. SUBSTANCE: proposed coat used for cutting tools made from hard alloy materials consists of three layers first layer consists of Ti_xAl_1-xN, where x is within 0.4 to 0.6 and has thickness of 0.5 to 1 mkm. Second layer of coat has thickness of 1 to 2 mkm and consists of HfN_y, where y is within 0.4 to 0.6 and third layer, 3 to 4 mkm thick consists of Hf_zAl_1-zN, where z is between 0.2 and 0.3. EFFECT: enhanced serviceability of tools at retained sharpness of cutting edge. 7 tbl, 1 ex