Preparation method of thin-shell structure zirconia powder for thermal spraying

Abstract

The invention discloses a preparation method of thin-shell structure zirconia powder for thermal spraying, which includes steps of step 1, preparing porous zirconia powder with grain diameter of 20-106 mu m by spraying and prilling, and calcining the prepared powder at 800-1000 DEG C; preserving temperature for 1-5 hours; step 2, delivering the calcined powder to a plasma spray gun to nodulize. The method is characterized in that a heat insulation zone is arranged in the zone along 10-500 mm of axial direction of a flame flow and 10-50 mm in a radial direction of a spray gun outlet, and the temperature in the heat insulation zone is not less than the melt point of the zirconia powder; step 3, collecting the cooled powder at outside of the heat insulation zone. Through arranging the lengthof the control zone, the hollow degree of the powder can be controlled, thus the powder with different hollow degrees can be acquired. For adopting the heat insulation method, additional heating device is not required to add. Therefore, the method is simple and feasible, and low in cost.

Description

technical field [0001] The invention belongs to the field of ceramic materials, and in particular relates to a method for preparing zirconia powder with a thin shell structure for thermal spraying. Background technique [0002] Zirconia coating has a high melting point and low thermal conductivity, and is widely used in thermal protection of components working at high temperatures, such as turbine blades, flame tubes of aero-engines, nozzles of rocket engines, etc. Depending on the temperature, zirconia has three different phase structures: monoclinic, tetragonal and cubic, and the phase transition process is accompanied by a large volume change. Therefore, during use, usually according to the application environment, in zirconia Add phase stabilizers such as yttrium oxide, magnesium oxide, calcium oxide, cerium oxide, etc. to inhibit phase transition and prevent volume change from causing coating cracking. [0003] Common preparation methods for zirconia coatings include...

AI Technical Summary

Problems solved by technology

However, due to the large temperature gradient of the plasma spray gun or the flame spray gun, the high melting point of the zirconia powder, the low thermal conductivity, and the short heating time of the powder in the flame flow, the temperature of the gas in the droplet is not high, and the flame flow The temperature at the end is often lower than the melting point of zirconia, causing the shell of the molten droplet to solidify and cannot continue to expand. Therefore, the hollowness of most of the particles prepared by this method is relatively low (generally less than 30%)

Images