Method for preparing matrix protective coating

Abstract

Disclosed a method for preparing a matrix protective coating, including a preprocessing step and a like transfer membrane coating preparation step. The like transfer membrane coating preparation step includes the following steps: mixing, drying and cooling YSZ powder and polytetrafluoroethylene powder to obtain a mixture, and then spraying the mixture onto the surface of a preprocessed matrix by an atmospheric plasma spraying method, wherein spraying parameters are set as follows: a moving speed of a spray gun is 440-460 mm/s; the current is 550-600 A, the voltage is 40-50 V, and the power is 24.8-30 kW; the compressed air is 0.6-0.7 MPa; the powder feeding carrier gas Ar is 3-6 L/min; a powder feeding rate is 25-28 g/min; and a spraying distance is 108-112 mm. The wear resistance of the coating of the present invention is significantly improved; the corrosion resistance is excellent; and the superhydrophobic property is excellent.

1 . A method for preparing a matrix protective coating, comprising a preprocessing step and a like transfer membrane coating preparation step, wherein the like transfer membrane coating preparation step comprises the following steps:
 mixing, drying and cooling yttria stabilized zirconia (YSZ) powder and polytetrafluoroethylene powder to obtain a mixture, and then spraying the mixture onto a surface of a preprocessed matrix by an atmospheric plasma spraying method; during spraying, direct current (DC) arc is generated between a cathode and an anode, which heats and ionizes an working gas into a plasma and ejects the plasma from a nozzle to form a plasma flame; the plasma flame includes an inner flame and an outer flame; a high-temperature zone having a temperature far higher than a vaporization temperature of the polytetrafluoroethylene powder is formed in the inner flame and a low-temperature zone having a temperature lower than the high-temperature zone is formed in the outer flame; the mixture is fed by the outer flame; the polytetrafluoroethylene powder is completely melt and the YSZ powder is partially melt molten polytetrafluoroethylene powder and molten YSZ powder are sprayed onto the matrix to form a deposited coating; a surface of the deposited coating is impacted by a non-molten YSZ powder; the non-molten YSZ forms a continuous skeleton structure to fix the molten polytetrafluoroethylene powder;   wherein spraying parameters of the atmospheric plasma spraying are set as follows: a moving speed of a spray gun is 440-460 mm/s; a current is 550-600 A, a voltage is 40-50 V, and a power is 24.8-30 kW; a intensity of pressure of a compressed air is 0.6-0.7 MPa; the compressed air is used to carry and propel the mixture; powder feeding carrier gas Ar is 3-6 L/min; a powder feeding rate is 25-28 g/min; and a spraying distance is 108-112 mm.   
     
     
         2 . The method for preparing the matrix protective coating according to  claim 1 , wherein the preprocessing step comprises a sand blasting step. 
     
     
         3 . The method for preparing the matrix protective coating according to  claim 2 , wherein sand blasting parameters are set as follows: 0.3-0.4 MPa air is taken as power; a spraying distance is 100-130 mm; an injection angle is 70°-90°; the injection angle is an angle between the surface of the preprocessed matrix and a blasting stream; and 60-150-mesh white fused alumina abrasive is injected to the surface of the matrix. 
     
     
         4 . The method for preparing the matrix protective coating according to  claim 1 , wherein a mixing ratio of YSZ powder to polytetrafluoroethylene powder is (92%-93%): (7%-8%), by mass percent. 
     
     
         5 . The method for preparing the matrix protective coating according to  claim 1 , wherein drying refers to drying for 3 hat 50-90° C. 
     
     
         6 . The method for preparing the matrix protective coating according to  claim 1 , wherein a thickness of a like transfer membrane coating is 20 μm-40 μm. 
     
     
         7 . The method for preparing the matrix protective coating according to  claim 1 , wherein the matrix is metal or ceramic material.