METHOD OF LOW-TEMPERATURE APPLICATION OF NANOCRYSTALLINE COATING FROM ALPHA-OXIDE ALUMINUM Russian patent published in 2019 - IPC B82B3/00 C23C14/24 C23C14/08 

FIELD: technological processes.

SUBSTANCE: method includes applying an isostructural chromium oxide sublayer to the product surface, heating the product, melting and evaporating aluminum, and depositing a coating on the product surface in an oxygen-argon discharge plasma under conditions of ion bombardment. Concentration of argon-oxygen plasma and the rate of evaporation of aluminum regulate independently and over a wide range by changing the current distribution between the crucible anode, in which the melting and evaporation of aluminum occurs, and a hollow anode-ionizer, through which oxygen is injected. Formation of coatings with the structure of alpha-alumina is achieved by the fact that for a given value of the rate of evaporation of aluminum, set the value of the bias potential on the products and the current in the anode-ionizer circuit, in which the required for the formation of the nanocrystalline alpha phase of aluminum oxide current density and ion energy on the surface of the growing coating. For the formation of a coating with the structure of the alpha phase of aluminum oxide with a speed of 3–5 mcm/h at a product temperature of 600 °C, the surface temperature of the melt is 950–1,000 °C with an ion current density and displacement potential in the range of 3–10 mA/cm² and 25–200 V, respectively.

EFFECT: method is proposed for producing an alpha alumina nanocrystalline coating at high speed at a lower temperature.

1 cl, 2 dwg