METHOD FOR SPRAYING A GRADIENT COATING BASED ON A COMPOSITE POWDER OF THE Al:SiN:SiAlON SYSTEM Russian patent published in 2022 - IPC C23C4/10 C23C4/12 C23C24/04 

FIELD: coatings.

SUBSTANCE: invention relates to a method for creating a microhardness-gradient wear-resistant coating based on a composite volume-reinforced powder of the Al:Si₃N₄:SiAlON system. Aluminium powder used as a matrix, with a particle size of 80 to 130 mcm, is mixed with plasma-chemical powder of Si₃N₄ used as a hardening phase in an amount of 55 wt.%, with particles of fibrous shape with a diameter below 100 nm and a diameter-to-length ratio of 1:20. Mechanosynthesis of the resulting powder mixture is performed on an attrition unit for 20 minutes at a rotation speed of the cups of 1,200 to 1,400 rpm, resulting in a composite powder for creating an adhesive layer containing 5 wt.% of the volume-reinforcing SiAlON phase. The aluminium powder used as a matrix, with a particle size of 80 to 130 mcm, is then mixed with plasma-chemical powder of Si₃N₄ used as a hardening phase in an amount of 65 wt.%, with particles of fibrous shape with a diameter below 100 nm and a diameter-to-length ratio of 1:20. Mechanosynthesis of the resulting powder mixture is performed on an attrition unit, resulting in a composite powder for creating a periphery layer containing 8 wt.% of the volume-reinforcing SiAlON phase. Layer-by-layer supersonic cold dynamic gas spraying is performed of said composite powder for creating an adhesive layer and said composite powder for forming a peripheral layer on a substrate at an air flow rate of 500 to 1200 m/s.

EFFECT: creation of a gradient coating based on a composite volume-reinforced powder material of the Al:Si₃N₄:SiAlON system with a hardness of up to 7 GPa, an adhesion up to 60 MPa, and a porosity below 1%.

1 cl, 3 dwg, 2 ex