Laser-plasma Spray Thermal Barrier Coating Structure And High Temperature Performance Research

As the aircraft engine,in order to ensure the hot end of engine parts under the condition of high temperature and high stress can safe and reliable work,need to have a certain strength and at the same time has good high temperature oxidation resistance,can be appropriate in the preparation of high temperature alloy surface protective coating.Thermal barrier coatings?TBCs,Thermal barrier coatings?has the stable chemical properties at high temperatures and the advantages of good heat insulation effect and in hot end components of aircraft engine is widely used,the heat insulation effect with up to 170 ?,can effectively improve the high temperature tolerance and work efficiency.Engine blades,the author of this paper,the use of laser cladding technology in the turbine blade surface preparation CoCrTaAlY alloy bonding layer,then use of plasma spraying technology in bonding layer surface spraying 8wt%Y2O3-ZrO₂?YSZ?ceramic layer,and the CoCrTaAlY coating and microstructures and properties of thermal barrier coating is analyzed.Geometric morphology research process parameters on the cladding layer,the influence of the analysis of the cladding coating changing with the laser power and scanning speed,and the test of thermal barrier coatings of high temperature oxidation resistance and thermal shock resistance.?1?Under the same laser power,with the increase of the laser scanning speed,the cladding layer thickness and width is reduced,and the shape coefficient and the wetting angle increases;under the same laser scanning speed,with the increase of the laser energy density,thickness of cladding coating and the width increases,the cladding coating shape coefficient and wetting angle decreased.Under the same scan rate,dilution rate increased with the increase of laser power increasing;under the same laser power,the dilution rate with the increase of scanning speed significantly lower first.Combining CoCrTaAlY material properties of alloy powder,when P = 2.7 kW,3.2 kW,v = 8 mm/s dilution rate?11%?13%?can be obtained when the suitable cladding layer.?2?Preparation of CoCrTaAlY coating using laser cladding is mainly composed of y/y'-?Fe,Al?and M?Ta,Si?C phase composition,laser cladding rapid condensation characteristics,easy to form stable phase.Matlab simulation model of a heat source,analysis with the increase of temperature gradient and cooling speed,cellular crystal in the cladding layer into dendrites,which in turn generates isometric dendrite.?3?The ZrO₂ ceramic layer prepared by plasma spraying method mainly in the form of tetragonal phase?t?,the cubic phase?c?and a small amount of monoclinic phase?m?;After 100 h the high temperature oxidation,only CoCrTaAlY coating sample oxidation weight nearly 0.12 g/cm2,and the YSZ coating sample oxidation cumulative increase major is about 0.08 g/cm2,the oxidation weight gain in lower value by 1/3,effectively promotes the high temperature oxidation resistance of the material;After oxidation coating of t-ZrO₂ to m-ZrO₂,makes the m-ZrO₂ increase.When YSZ samples of plasma spraying coating under 900 ? heat shock 20 times,began to appear on the surface of ceramic layer local tiny crack visible to the naked eye,as the experiment continued,crack increases gradually,to 25 thermal shock crack throughout the entire surface,crack has formed after 30 times extremely obvious cracks.