COMPOSITION OF MIXED CUTTING CERAMICS AND METHOD FOR MANUFACTURE THEREOF Russian patent published in 2022 - IPC C22C1/10 C22C29/00 B22F3/14 B22F3/24 C04B35/01 B23P15/28 

FIELD: powder metallurgy.

SUBSTANCE: invention relates to powder metallurgy, in particular, to manufacture of high-strength ceramic cutting inserts. Invention can be used to equip cutting tools for processing hard-to-process steels and alloys or high-strength and grey cast irons. Mixed cutting ceramics contain, % wt.: aluminium oxide 17 to 24, silicon nitride 19 to 20, silicon oxide 19 to 20, cobalt oxide 4 to 5, zirconium carbide 3 to 4, tantalic carbide 7 to 8, titanium carbide 19 to 20, tungsten carbide 5 to 6. The mixture of silicon oxide, aluminium oxide, and silicon nitride is calcined at a temperature of 1,700 to 1,750 °C, subjected to fine vibration milling on a vibration unit for 3.5 to 4.0 h, and dried. After drying, cobalt oxide, zirconium carbide, tantalic carbide, titanium carbide, and tungsten carbide are added and mixed until homogeneously distributed throughout the volume and an aqueous suspension is formed, followed by adding up to 3% deoxidising additives of catalysts in the form of magnesium oxide MdO, calcium oxide CaO, sodium oxide Na₂O to said suspension and subjecting to spray drying resulting in a mixture. The resulting mixture is pressed, forming a cutting insert, sintered at a temperature of 3,850 to 3,900 °C and subjected to short-term annealing, holding for 10.0 to 15.0 min at a temperature of 1,600 to 1,650 °C. The annealing is followed by machining until the roughness of the faces equal to 0.08–0.16 mcm is achieved.

EFFECT: higher intercrystalline corrosion resistance, thermal wear resistance, plasticity, impact strength and operability, yield strength during hot pressing and sintering of the inserts, rigidity and hardness.

2 cl, 1 tbl, 1 ex