| Plasma spray-physical vapor deposition（PS-PVD）combines the advantages of plasma spray（PS）and electron beam physical vapor deposition（EB-PVD）,and is recognized as one of the most promising advanced aero-engine thermal barrier coating preparation technologies.The key to the preparation of high performance column thermal barrier coatings by PS-PVD technology lies in the realization of spray powder gasification by plasma jet.As it becomes more and more difficult to improve the performance of coatings,it is necessary to have a deeper understanding of the characteristics of PS-PVD plasma jet in order to obtain more excellent coatings.As the core part of plasma spray gun,the anode size and structure directly affect the plasma jet characteristics.In order to explore the influence of the spray gun anode on the plasma jet characteristics,coating structure and performance,this article starts from the spray gun anode structure design of homemade three different size structure of plasma spray gun anode（#1,#2,#3）,deposition coating for feather columnar,combining spectral diagnosis（OES）and numerical simulation,analyses the features and the jet plasma jet powder gasification,phase composition,microstructure and mechanical properties of the coating were characterized by X-ray diffractometer,scanning electron microscope and nano indentation.The bonding strength,thermal shock and scour resistance of the coating were tested by tensile test,thermal shock test and particle scour test.The main results are as follows:（1）Different anodes of plasma spray gun have great influence on the characteristics of PS-PVD plasma jet and particle gasification.Among the plasma jets produced by anodes#1,#2 and#3,anodes#3 has the narrowest jet width.The results of the OES study show that the electron density and electron temperature of plasma jet at#3 anode are 1.57×1015/cm3 and 3470.70K,respectively,when no powder is fed,which are higher than those at#1 and#2 anode.After powder feeding,the electron density and electron temperature in plasma jet decrease in different degrees,and the jet drop at#3 anode decreased the most.Combined with the calculation results of computer numerical simulation,it can be seen that 7YSZ powder gasification is the most abundant in the#3 anode jet.（2）The coatings obtained by the#1,#2 and#3 anodes all showed a typical feather-column structure,and there was no obvious difference in the coating phase composition.The#3 anode can significantly improve the deposition efficiency of the coating,up to 0.51μm/pass.The results of nano-indentation show that the hardness of each growth layer of the three coatings gradually increases from bottom to top,and the change is small.Among them,the coating prepared by#3anode has the highest average hardness and average Young’s modulus,reaching 13.57GPa and166.84GPa,respectively.（3）The coating prepared by#3 anode has more excellent bonding strength,thermal shock and erosion resistance.The experimental results show that the bonding strength of the coating prepared by the#3 anode is the most excellent,which is 54.5MPa.After 200 thermal shock tests,the coating prepared by#3 anode did not appear large-scale spalling,only small cracks were found at the edge,and the center area remained well.When the sand consumption in the particle scouring experiment reached 100g,the coating prepared by the#3 anode showed the lowest scouring rate during the scouring process,and the weight loss was only 0.15g. |
