Novel YSZ thick thermal barrier coating and preparation method thereof

Abstract

The invention provides a YSZ (Yttrium Stabilized Zirconium) composite thermal barrier coating. The YSZ composite thermal barrier coating comprises a bonding layer and a composite lamination layer, wherein the bonding layer is compounded on a substrate; the composite lamination layer is compounded on the bonding layer and is formed by stacking a YSZ ceramic material layer and an RMgAl11O19 material layer; r is one or more of La, Nb, Sm and Gd; the composite lamination has a crack structure. The YSZ thick thermal barrier coating with the shell-imitating structure has the advantages that in-situ endogenous interlayer cracks are formed in high-temperature service, the cracks spread to a'mud-brick 'interface, and the interlayer cracks can release thermal expansion mismatching residual thermal stress generated in the thermal cycle process and can also release aging residual thermal stress generated by the coating at high temperature; the heat-insulating material has the advantages of high heat conductivity, long heat cycle life, prevention of direct diffusion of heat flow to a matrix through cracks, improvement of the heat-insulating property, service at a high temperature of 1350 DEG C or above, and good application prospects in hot end components of new-generation aero-engines, heavy duty gas turbines and hypersonic aircrafts.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature thermal barrier coatings, and relates to a YSZ composite thermal barrier coating and a preparation method thereof, and in particular to a novel YSZ thick thermal barrier coating and a preparation method thereof. Background Art

[0002] Yttria partially stabilized zirconia (Y2O3 partially-stabilized ZrO2, YSZ) thermal barrier coatings have the advantages of high melting point, high hardness, high fracture toughness and low thermal conductivity, and are widely used in thermal protection of hot end components of aircraft engines and industrial gas turbines. With the continuous increase in the gas inlet temperature of aircraft engines and industrial gas turbines, YSZ thermal barrier coatings can no longer meet the requirements of high temperature resistance, high thermal insulation and long life thermal protection. The use of YSZ thick thermal barrier coatings (thickness ≥ 500μm) is a simple and effective method to achieve high thermal insulation performance. However, traditional YSZ thick thermal barrier coatings will form large residual thermal stress during service above 1200℃, the coating is easy to fall off, and the thermal cycle life is low, which greatly limits the high temperature application of traditional YSZ thick thermal barrier coatings.

[0003] Therefore, the design of new coating structure is an effective way to solve the low life of YSZ thick thermal barrier coating. At present, there are mainly partitioned crack structure and functional gradient structure. The partitioned crack structure is to design vertical cracks through the coating to release residual thermal stress, thereby improving the thermal cycle life of the coating. However, the through crack also provides a channel for heat flow transmission, which is not conducive to the thermal insulation performance of the coating. The improvement of its thermal cycle life is at the expense of some thermal insulation performance. Therefore, the partitioned crack structure YSZ thick thermal barrier coating is difficult to meet the requirements of high temperature resistance and high thermal insulation. The functional gradient structure is to design a composite layer with a continuous gradient change in composition between the YSZ ceramic layer and the substrate to reduce the thermal expansion mismatch between the coating and the substrate, reduce the thermal expansion mismatch stress, and thus improve the thermal cycle life of the coating. However, the functional gradient structure YSZ thick thermal barrier coating is difficult to overcome the coating damage caused by the aging residual thermal stress generated by phase change, sintering and oxidation when serving above 1200℃. Therefore, the functional gradient structure YSZ thick thermal barrier coating is also difficult to meet the requirements of high temperature resistance and long life.

[0004] Therefore, how to find a more suitable method to solve the above-mentioned technical problems existing in the existing YSZ thick thermal barrier coatings has become one of the focuses of widespread attention of many cutting-edge scientific researchers in this field. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a YSZ composite thermal barrier coating and a preparation method thereof, in particular, a new type of YSZ thick thermal barrier coating. The YSZ thick thermal barrier coating with a new shell-like structure provided by the present invention has in-situ intrinsic interlayer cracks, which can not only release the residual thermal stress caused by thermal expansion mismatch, but also release the residual thermal stress caused by aging. Compared with through cracks, interlayer cracks make it difficult for heat flow to diffuse directly to the substrate surface through cracks. Moreover, the process is simple, the conditions are mild, the controllability is good, and the stability is high, which is more conducive to the promotion and application of large-scale industrial production.

[0006] The present invention provides a YSZ composite thermal barrier coating, comprising: a bonding layer for bonding on a substrate and a YSZ ceramic material layer and RMgAl bonded on the bonding layer. 11 O 19 A composite layup in which layers of material are stacked;

[0007] Wherein, R is one or more of La, Nb, Sm and Gd;

[0008] The composite laminate has a crack structure therein.

[0009] Preferably, the composite laminate has a YSZ ceramic material layer and a RMgAl 11 O 19 A multi-layer structure formed by stacking material layers in sequence; the number of layers of the multi-layer structure is greater than or equal to 2;

[0010] The bonding layer comprises a metal bonding layer;

[0011] The composite laminate has a laminated structure of a brick layer and a mud layer;

[0012] The thickness of the YSZ ceramic material layer is greater than or equal to RMgAl 11 O 19 The thickness of the material layer;

[0013] The composite thermal barrier coating is a thick thermal barrier coating.

[0014] Preferably, the material of the bonding layer includes MCrAlY, wherein M is Ni and / or Co;

[0015] The YSZ ceramic material layer is a brick layer;

[0016] The RMgAl 11 O 19 The material layer is a mud layer;

[0017] The YSZ ceramic material layer and RMgAl 11 O 19 The thickness ratio of the material layer is (1-1.5):1;

[0018] The crack is specifically a longitudinal crack in the relative thickness direction;

[0019] The cracks are located in the mud layer.

[0020] Preferably, the cracks are longitudinal interlayer cracks generated in situ in the mud layer;

[0021] The propagation of the longitudinal interlayer crack stops at the interface between the mud layer and the brick layer;

[0022] The thickness of the bonding layer is 100 to 200 μm;

[0023] Single YSZ ceramic material layer and RMgAl 11 O 19 The thickness of the brick-mud elementary laminate formed by stacking the material layers is 50 to 200 μm;

[0024] The thickness of the YSZ composite thermal barrier coating is 500-1500 μm;

[0025] The YSZ composite thermal barrier coating is specifically a YSZ thick thermal barrier coating with a shell-like structure.

[0026] The present invention provides a method for preparing a YSZ composite thermal barrier coating, comprising the following steps:

[0027] 1) Adopting atmospheric plasma spraying method to deposit bonding layer material powder on the substrate to obtain a bonding layer;

[0028] 2) Using atmospheric plasma spraying, YSZ ceramic material powder and RMgAl 11 O 19 Material powders are sequentially deposited on the bonding layer to form a brick-mud element stack;

[0029] Wherein, R is one or more of La, Nb, Sm and Gd;

[0030] 3) Repeat step 2) to form a composite laminate in which multiple brick-mud elementary laminates are deposited in sequence to obtain a YSZ composite thermal barrier coating.

[0031] Preferably, the bonding layer material comprises MCrAlY; wherein M is Ni and / or Co;

[0032] The particle size of the bonding layer material powder is -130+325 mesh;

[0033] The substrate is specifically a pretreated substrate;

[0034] The pretreatment includes one or more steps of sandblasting, ultrasonic cleaning and drying.

[0035] Preferably, in step 1), the spraying current of the atmospheric plasma spraying is 600-700A;

[0036] The argon gas flow rate of the atmospheric plasma spraying is 45-50 SLPM;

[0037] The hydrogen flow rate of the atmospheric plasma spraying is 6 to 10 SLPM;

[0038] The carrier gas flow rate of the atmospheric plasma spraying is 2.5-3.0 SLPM;

[0039] The spraying distance of the atmospheric plasma spraying is 90 to 110 mm;

[0040] The spray gun speed of the atmospheric plasma spraying is 950-1050 mm / s.

[0041] Preferably, the particle size of the YSZ ceramic material powder is -200+325 mesh;

[0042] The RMgAl 11 O 19 The particle size of the material powder is -130+325 mesh;

[0043] The RMgAl 11 O 19 The material powder is specifically RMgAl 11 O 19 , a mixed powder of ammonium citrate and gum arabic;

[0044] The RMgAl 11 O 19 , ammonium citrate and gum arabic is 100:(0.6~1.0):(1.8~2.2).

[0045] Preferably, the RMgAl 11 O 19 The material powder is prepared by the following steps:

[0046] a) The RE2O3, MgO and Al2O3 powders are ball-milled to obtain a slurry, which is then dried and crushed, and then subjected to a solid phase reaction to obtain RMgAl 11 O 19 ;

[0047] The temperature of the solid phase reaction is 1550-1600°C;

[0048] The solid phase reaction time is 10 to 15 hours;

[0049] b) RMgAl obtained by the above steps 11 O 19, ammonium citrate, gum arabic and water are mixed to obtain a mixed slurry, which is then spray granulated to obtain RMgAl 11 O 19 Material powder.

[0050] Preferably, in step 2), the spraying current of the atmospheric plasma spraying is 550-650A;

[0051] The argon gas flow rate of the atmospheric plasma spraying is 33-38 SLPM;

[0052] The hydrogen flow rate of the atmospheric plasma spraying is 10-14 SLPM;

[0053] The carrier gas flow rate of the atmospheric plasma spraying is 3.0-3.5 SLPM;

[0054] The spraying distance of the atmospheric plasma spraying is 96 to 110 mm;

[0055] The spray gun speed of the atmospheric plasma spraying is 950-1050 mm / s.

[0056] The present invention provides a YSZ composite thermal barrier coating, comprising: a bonding layer for bonding on a substrate and a YSZ ceramic material layer and RMgAl bonded on the bonding layer. 11 O 19 A composite laminate of stacked material layers; wherein R is one or more of La, Nb, Sm and Gd; and the composite laminate has a crack structure. Compared with the prior art, in response to the difficulties in high-temperature thermal protection of YSZ thick thermal barrier coatings, the present invention is based on the bionic idea and creatively designs a YSZ composite thermal barrier coating with a specific structure and composition. This is a YSZ thick thermal barrier coating with an in-situ endogenous interlayer crack shell-like structure. The "mud-brick" structure composed of an organic soft phase and a calcium carbonate hard phase derived from shells. The present invention designs the YSZ thick thermal barrier coating into a shell-like "mud-brick" structure, and the shell-like primitives are composed of a YSZ "brick layer" and RMgAl 11 O 19 (R=La, Nb, Sm, Gd, RMA) "mud layer", the melting point, hardness and fracture toughness of RMA are relatively lower than those of YSZ, so RMA is designed as a "mud layer" material, and the thickness of the shell-like element "mud layer" is not greater than the thickness of the "brick layer".

[0057] The present invention also provides a method for preparing a YSZ composite thermal barrier coating. Both the YSZ "brick layer" and the RMA "mud layer" are prepared by atmospheric plasma spraying technology. A YSZ thick thermal barrier coating with a target thickness is formed by spraying a plurality of shell-like primitives. The YSZ thick thermal barrier coating prepared by the present invention is used at high temperatures (>1200°C). In-situ endogenous longitudinal cracks are formed in the "mud layer", and the propagation of the longitudinal cracks stops at the interface between the "mud-brick" and is difficult to enter the "brick layer", thereby forming interlayer cracks in the "mud layer". A YSZ thick thermal barrier coating with an in-situ endogenous interlayer crack shell-like structure is prepared, such as Figure 1 As shown, Figure 1 The low-magnification and high-magnification SEM images of the YSZ thick thermal barrier coating with a shell-like structure prepared by the present invention are shown in Figure 1. (a) shows the "mud-brick" structure of the shell, and (b, c) show the low-magnification SEM image (b) and high-magnification SEM image (c) of the cross section of the YSZ thick thermal barrier coating with a shell-like structure after high-temperature thermal cycling.

[0058] Compared with the current partitioned crack new structure and functional gradient new structure YSZ thick thermal barrier coating, the shell-like new structure YSZ thick thermal barrier coating provided by the present invention has the biggest feature of in-situ internal interlayer cracks, which has the advantage of not only releasing the residual thermal stress caused by thermal expansion mismatch, but also releasing the aging residual thermal stress. In addition, compared with through cracks, interlayer cracks make it difficult for heat flow to diffuse directly to the substrate surface through cracks. Therefore, the in-situ internal interlayer crack shell-like structure proposed by the present invention can effectively solve the problem of YSZ thick thermal barrier coating with high temperature resistance, high thermal insulation and long life.

[0059] The YSZ thick thermal barrier coating with in-situ endogenous interlayer cracks and shell-like structure provided by the present invention and its preparation method effectively solve the difficult problem of YSZ thick thermal barrier coating with high temperature resistance, high thermal insulation and long service life. Compared with the YSZ thick thermal barrier coating with traditional structure, the YSZ thick thermal barrier coating with shell-like structure designed by the present invention has the characteristics of forming in-situ endogenous interlayers instead of through cracks during high-temperature service, and the crack propagation stops at the interface of "mud-brick". The interlayer cracks formed by the "mud layer" can not only release the residual thermal stress of thermal expansion mismatch generated during the thermal cycle, but also release the aging residual thermal stress generated by YSZ phase change and sintering at high temperature, which is beneficial to improve the thermal cycle life; in addition, compared with through cracks, interlayer cracks can effectively prevent heat flow from directly diffusing through cracks to reach the substrate, which is beneficial to improve the thermal insulation performance of the coating; in addition, the shell-like "mud-brick" unit composed of RMA and YSZ is more resistant to high temperature and thermal shock than a single YSZ "brick layer", and can be used at high temperatures of 1350℃ and above. The shell-like YSZ thick thermal barrier coating prepared by the present invention has good potential application prospects for high-temperature thermal protection of future new-generation aviation engines, heavy-duty gas turbines and hot-end components of hypersonic aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 The low-magnification and high-magnification SEM images of the YSZ thick thermal barrier coating with a shell-like structure prepared by the present invention;

[0061] Figure 2 This is a schematic SEM structural photograph of the coating cross section of the YSZ composite thermal barrier coating provided by the present invention;

[0062] Figure 3 This is a macroscopic photograph of the YSZ thick thermal barrier coating with a ceramic layer thickness of 500 μm prepared in Example 1 of the present invention after flame burning thermal cycle at 1350±25°C;

[0063] Figure 4 The macroscopic photograph and SEM photograph of the cross section of the YSZ thick thermal barrier coating with a shell-like structure prepared in Example 2 of the present invention after 1000 cycles of flame burning heat at 1350±25°C;

[0064] Figure 5 This is a macroscopic photograph of the YSZ thick thermal barrier coating with a shell-like structure prepared in Example 3 of the present invention after failure in a flame burning thermal cycle at 1400±25°C. DETAILED DESCRIPTION

[0065] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent claims of the present invention.

[0066] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0067] There is no particular restriction on the purity of all raw materials in the present invention. The present invention preferably uses analytically pure materials or materials with conventional purity requirements in the field of YSZ thermal barrier coating preparation.

[0068] The brands and abbreviations of all raw materials of the present invention are conventional brands and abbreviations in the art. Each brand and abbreviation is clear and definite in the field of its related use. Those skilled in the art can purchase them from the market or prepare them by conventional methods according to the brands, abbreviations and corresponding uses.

[0069] The abbreviations of the processes used in the present invention are all conventional abbreviations in the field. The specific steps and conventional parameters of each abbreviation are clear and definite in its relevant field. Those skilled in the art can implement them in a conventional manner based on the abbreviations.

[0070] The present invention provides a YSZ composite thermal barrier coating, comprising: a bonding layer for bonding on a substrate and a YSZ ceramic material layer and RMgAl bonded on the bonding layer. 11 O19 A composite layup in which layers of material are stacked;

[0071] Wherein, R is one or more of La, Nb, Sm and Gd;

[0072] The composite laminate has a crack structure therein.

[0073] In the present invention, the composite laminate preferably has a YSZ ceramic material layer and a RMgAl 11 O 19 A multi-layer structure is formed by stacking material layers in sequence; the number of layers of the multi-layer structure is preferably greater than or equal to 2.

[0074] In the present invention, the bonding layer preferably includes a metal bonding layer.

[0075] In the present invention, the composite laminate preferably has a laminate structure of a brick layer-mud layer.

[0076] In the present invention, the thickness of the YSZ ceramic material layer is preferably greater than or equal to RMgAl 11 O 19 The thickness of the material layer.

[0077] In the present invention, the composite thermal barrier coating is preferably a thick thermal barrier coating.

[0078] In the present invention, the material of the bonding layer preferably includes MCrAlY; wherein M is preferably Ni and / or Co, and more preferably Ni or Co.

[0079] In the present invention, the YSZ ceramic material layer is preferably a brick layer.

[0080] In the present invention, the RMgAl 11 O 19 The material layer is preferably a mud layer.

[0081] In the present invention, the YSZ ceramic material layer and the RMgAl 11 O 19 The thickness ratio of the material layers is preferably (1 to 1.5):1, more preferably (1.1 to 1.4):1, and even more preferably (1.2 to 1.3):1.

[0082] In the present invention, the cracks are preferably longitudinal cracks in the relative thickness direction.

[0083] In the present invention, the cracks are preferably located in the mud layer.

[0084] In the present invention, the cracks are preferably longitudinal interlayer cracks generated in situ in the mud layer.

[0085] In the present invention, the propagation of the longitudinal interlayer crack is preferably stopped at the interface between the mud layer and the brick layer.

[0086] In the present invention, the thickness of the adhesive layer is preferably 100 to 200 μm, more preferably 120 to 180 μm, and more preferably 140 to 160 μm, and specifically may be 150 μm.

[0087] In the present invention, a single YSZ ceramic material layer is combined with RMgAl 11 O 19 The thickness of the brick-mud element laminate formed by stacking material layers is preferably 50 to 200 μm, more preferably 80 to 170 μm, and even more preferably 110 to 140 μm.

[0088] In the present invention, the thickness of the YSZ composite thermal barrier coating is preferably 500-1500 μm, more preferably 700-1300 μm, and more preferably 900-1100 μm.

[0089] In the present invention, the YSZ composite thermal barrier coating is preferably a YSZ thick thermal barrier coating with a shell-like structure.

[0090] The present invention provides a method for preparing a YSZ composite thermal barrier coating, comprising the following steps:

[0091] 1) Adopting atmospheric plasma spraying method to deposit bonding layer material powder on the substrate to obtain a bonding layer;

[0092] 2) Using atmospheric plasma spraying, YSZ ceramic material powder and RMgAl 11 O 19 Material powders are sequentially deposited on the bonding layer to form a brick-mud element stack;

[0093] Wherein, R is one or more of La, Nb, Sm and Gd;

[0094] 3) Repeat step 2) to form a composite laminate in which multiple brick-mud elementary laminates are deposited in sequence to obtain a YSZ composite thermal barrier coating.

[0095] The present invention firstly adopts the atmospheric plasma spraying method to deposit the bonding layer material powder on the substrate to obtain the bonding layer.

[0096] In the present invention, the bonding layer material preferably includes MCrAlY, wherein M is preferably Ni and / or Co, and more preferably Ni or Co.

[0097] In the present invention, the particle size of the bonding layer material powder is preferably -130+325 mesh, more preferably -160+300 mesh, and more preferably -200+260 mesh.

[0098] In the present invention, the substrate is preferably a pretreated substrate.

[0099] In the present invention, the pretreatment preferably includes one or more steps of sandblasting, ultrasonic cleaning and drying, and more preferably includes multiple steps of sandblasting, ultrasonic cleaning and drying.

[0100] In the present invention, the spraying current of the atmospheric plasma spraying is preferably 600-700A, more preferably 620-680A, and more preferably 640-660A.

[0101] In the present invention, the argon gas flow rate of the atmospheric plasma spraying is preferably 45 to 50 SLPM, more preferably 46 to 49 SLPM, and more preferably 47 to 48 SLPM.

[0102] In the present invention, the hydrogen flow rate of the atmospheric plasma spraying is preferably 6-10 SLPM, more preferably 6.5-9.5 SLPM, more preferably 7-9 SLPM, and more preferably 7.5-8.5 SLPM.

[0103] In the present invention, the carrier gas flow rate of the atmospheric plasma spraying is preferably 2.5 to 3.0 SLPM, more preferably 2.6 to 2.9 SLPM, and more preferably 2.7 to 2.8 SLPM.

[0104] In the present invention, the spraying distance of the atmospheric plasma spraying is preferably 90 to 110 mm, more preferably 94 to 106 mm, and more preferably 98 to 102 mm.

[0105] In the present invention, the spray gun speed of the atmospheric plasma spraying is preferably 950 to 1050 mm / s, more preferably 970 to 1030 mm / s, and more preferably 990 to 1010 mm / s.

[0106] The present invention further uses atmospheric plasma spraying to mix YSZ ceramic material powder with RMgAl 11 O 19 Material powders are sequentially deposited on the bonding layer to form a brick-mud element stack;

[0107] Wherein, R is one or more of La, Nb, Sm and Gd.

[0108] In the present invention, the particle size of the YSZ ceramic material powder is preferably -200+325 mesh, more preferably -220+300 mesh, and more preferably -240+280 mesh.

[0109] In the present invention, the RMgAl 11 O 19The particle size of the material powder is preferably -130+325 mesh, more preferably -160+300 mesh, and more preferably -200+260 mesh.

[0110] In the present invention, the RMgAl 11 O 19 The material powder is preferably RMgAl 11 O 19 , ammonium citrate and gum arabic mixed powder.

[0111] In the present invention, the RMgAl 11 O 19 The mass ratio of ammonium citrate and gum arabic is preferably 100: (0.6-1.0): (1.8-2.2), more preferably 100: (0.65-0.95): (1.85-2.15), more preferably 100: (0.7-0.9): (1.9-2.1), more preferably 100: (0.75-0.85): (1.95-2.05).

[0112] In the present invention, the RMgAl 11 O 19 The material powder is preferably prepared by the following steps:

[0113] a) The RE2O3, MgO and Al2O3 powders are ball-milled to obtain a slurry, which is then dried and crushed, and then subjected to a solid phase reaction to obtain RMgAl 11 O 19 ;

[0114] The temperature of the solid phase reaction is 1550-1600°C;

[0115] The solid phase reaction time is 10 to 15 hours;

[0116] b) RMgAl obtained by the above steps 11 O 19 , ammonium citrate, gum arabic and water are mixed to obtain a mixed slurry, which is then spray granulated to obtain RMgAl 11 O 19 Material powder.

[0117] In the present invention, the temperature of the solid phase reaction is preferably 1550-1600°C, more preferably 1560-1590°C, and even more preferably 1570-1580°C.

[0118] In the present invention, the solid phase reaction time is preferably 10 to 15 hours, more preferably 11 to 14 hours, and more preferably 12 to 13 hours.

[0119] In the present invention, in the step 2), the spraying current of the atmospheric plasma spraying is preferably 550-650A, more preferably 570-630A, and more preferably 590-610A.

[0120] In the present invention, the argon gas flow rate of the atmospheric plasma spraying is preferably 33-38 SLPM, more preferably 34-37 SLPM, and more preferably 35-36 SLPM.

[0121] In the present invention, the hydrogen flow rate of the atmospheric plasma spraying is preferably 10-14 SLPM, more preferably 10.5-13.5 SLPM, more preferably 11-13 SLPM, and more preferably 11.5-12.5 SLPM.

[0122] In the present invention, the carrier gas flow rate of the atmospheric plasma spraying is preferably 3.0 to 3.5 SLPM, more preferably 3.1 to 3.4 SLPM, and more preferably 3.2 to 3.3 SLPM.

[0123] In the present invention, the spraying distance of the atmospheric plasma spraying is preferably 96 to 110 mm, more preferably 98 to 108 mm, more preferably 100 to 106 mm, and more preferably 102 to 104 mm.

[0124] In the present invention, the spray gun speed of the atmospheric plasma spraying is preferably 950 to 1050 mm / s, more preferably 970 to 1030 mm / s, and more preferably 990 to 1010 mm / s.

[0125] The present invention finally repeats step 2) to form a composite laminate in which multiple brick-mud elementary laminates are deposited in sequence, thereby obtaining a YSZ composite thermal barrier coating.

[0126] See also Figure 2 , Figure 2 This is a schematic SEM structural photograph of the coating cross section of the YSZ composite thermal barrier coating provided by the present invention.

[0127] The present invention is to complete and refine the overall technical solution, better ensure the combination and structure of the YSZ composite thermal barrier coating, and further improve the temperature resistance and heat insulation performance and service life of the YSZ composite thermal barrier coating. The above-mentioned YSZ composite thermal barrier coating and its preparation method may specifically include the following contents:

[0128] The YSZ thick thermal barrier coating is composed of a MCrAlY (M = Ni, Co, NiCo) metal bonding layer and a number of YSZ / RMA imitation shell primitives. The substrate on which the coating is deposited is a nickel-based high-temperature alloy. The present invention takes DZ125 high-temperature alloy as an example. The thickness of the metal bonding layer is about 150 μm, the thickness of the imitation shell primitive is 100-200 μm, the thickness ratio of the YSZ "brick layer" to the RMA "mud layer" in the imitation shell primitive is 1-1.5, and the thickness of the ceramic layer formed by stacking the imitation shell "mud-brick" primitives is 500-1000 μm.

[0129] Specifically, YSZ and MCrAlY powders are commercial powders purchased directly, and the powders are spherical particles. The particle size of YSZ powder is -200+325 mesh, and the particle size of MCrAlY powder is -130+325 mesh.

[0130] RMA spray powder is prepared by high-temperature solid-phase reaction synthesis and spray granulation technology, and the preparation process is as follows: first, weigh RE2O3, MgO and Al2O3 raw material powders (purity>99.9%) according to the stoichiometric ratio of RMA and pour them into a ball mill; add an appropriate amount of deionized water and zirconium oxide grinding balls to the ball mill, and then place the ball mill on a roller ball mill for 8-12 hours to obtain a slurry; the slurry is dried in an oven at 80-120°C and then crushed with a jaw crusher, and then passed through a 60-mesh sieve, and the powder that is not screened is crushed again until it is completely screened; the powder that is screened is loaded into a zirconia crucible, placed in a 1550-1600°C box furnace and heated for 10-15 hours to undergo solid-phase reaction to synthesize RMA; the obtained RMA block is crushed with a jaw crusher, sieved with a 60-mesh sieve, and the powder that is not screened is crushed again until it is completely screened. The RMA powder, ammonium citrate and gum arabic under the sieve are placed in a ball mill at a weight ratio of 100: (0.6-1.0): (1.8-2.2), and appropriate amount of deionized water and zirconium oxide grinding balls are added, and the ball mill is used for 60-80 hours in a roller ball mill; the ball-milled slurry is spray-granulated in a spray dryer, and then the spray-granulated powder is sieved with 130 mesh and 325 mesh sieves, and the -130+325 mesh granulated powder is collected for atmospheric plasma spraying.

[0131] Specifically, the preparation process of the YSZ thick thermal barrier coating is as follows: 1) DZ125 substrate surface pretreatment: sandblast the substrate surface with 36# corundum sand, then ultrasonically clean it with ethanol in an ultrasonic cleaner for 2-4 minutes, and dry it with a hair dryer before spraying;

[0132] 2) Preparation of MCrAlY bonding layer: atmospheric plasma spraying parameters are spraying current 600-700A, argon flow 45-50SLPM, hydrogen flow 6-10SLPM, carrier gas flow 2.5-3.0SLPM, spraying distance 90-110mm, spray gun speed 950-1050mm / s. MCrAlY powder is fed into the plasma flame flow through a powder feeding tube for heating and acceleration. The formed high-speed droplets impact the surface of the pre-treated substrate and spread and deposit. Through repeated spraying, a metal bonding layer with a thickness of about 150μm is formed on the substrate surface;

[0133] 3) Preparation of shell-like "mud-brick" ceramic layer: atmospheric plasma spraying parameters are spraying current 550-650A, argon flow rate 33-38SLPM, hydrogen flow rate 10-14SLPM, carrier gas flow rate 3.0-3.5SLPM, spraying distance 90-110mm, and spray gun speed 950-1050mm / s.

[0134] According to the design of shell-like primitive thickness, the thickness ratio design of "brick layer" and "mud layer" in the primitive and the total thickness design of "mud-brick" stacking, the thickness of YSZ "brick layer", the thickness of RMA "mud layer" and the number of shell-like "mud-brick" primitives are calculated. First, the YSZ powder is fed into the plasma flame flow for heating and acceleration through a powder feeding tube, and the formed high-speed droplets hit the surface of the bonding layer and spread and deposit. Through repeated spraying, a YSZ "brick layer" with a designed thickness is formed on the surface of the bonding layer. Then, the RMA powder is fed into the plasma flame flow for heating and acceleration through a powder feeding tube, and the formed high-speed droplets hit the surface of the YSZ "brick layer" and spread and deposit. Through repeated spraying, an RMA "mud layer" with a designed thickness is formed on the surface of the YSZ "brick layer", thereby completing the preparation of the first shell-like "mud-brick" element; similarly, the second shell-like "mud-brick" element is sprayed on the surface of the first shell-like "mud-brick" element by atmospheric plasma, and the spraying is repeated until the designed number of shell-like "mud-brick" elements is completed, thereby preparing a shell-like structure YSZ thick thermal barrier coating that meets the thickness design requirements.

[0135] The prepared YSZ thick thermal barrier coating with shell-like structure was subjected to flame burning thermal cycle test. During the thermal cycle, the flame burned the coating surface from room temperature to (1350-1400) ± 25 °C within 2 minutes, and then kept burning at a constant temperature. When the burning time reached 6 minutes, the flame left the coating surface, and the back of the substrate was cooled with compressed air for 2 minutes to reduce the coating surface temperature to room temperature, thus completing a thermal cycle. The test was repeated in this way to complete the number of thermal cycles required by the test design. During the high-temperature thermal cycle, the shell-like RMA "mud layer" formed in-situ endogenous interlayer cracks.

[0136] The above content of the present invention provides a novel YSZ thick thermal barrier coating and a preparation method thereof. The YSZ composite thermal barrier coating with a specific structure and composition designed by the present invention is a YSZ thick thermal barrier coating with an in-situ endogenous interlayer crack imitating shell structure. The "mud-brick" structure composed of an organic soft phase and a calcium carbonate hard phase originates from the shell. The present invention designs the YSZ thick thermal barrier coating into a shell-like "mud-brick" structure, and the shell-like primitives are composed of a YSZ "brick layer" and RMgAl 11 O 19 (R=La, Nb, Sm, Gd, RMA) "mud layer", the melting point, hardness and fracture toughness of RMA are relatively lower than those of YSZ, so RMA is designed as a "mud layer" material, and the thickness of the shell-like element "mud layer" is not greater than the thickness of the "brick layer".

[0137] The present invention also provides a method for preparing a YSZ composite thermal barrier coating. Both the YSZ "brick layer" and the RMA "mud layer" are prepared by atmospheric plasma spraying technology. A YSZ thick thermal barrier coating with a target thickness is formed by spraying a plurality of shell-like primitives. The YSZ thick thermal barrier coating prepared by the present invention is used at high temperatures (>1200°C). In-situ endogenous longitudinal cracks are formed in the "mud layer", and the propagation of the longitudinal cracks stops at the interface between the "mud-brick" and is difficult to enter the "brick layer", thereby forming interlayer cracks in the "mud layer". A YSZ thick thermal barrier coating with an in-situ endogenous interlayer crack shell-like structure is prepared, such as Figure 1 shown.

[0138] Compared with the current partitioned crack new structure and functional gradient new structure YSZ thick thermal barrier coating, the shell-like new structure YSZ thick thermal barrier coating provided by the present invention has the biggest feature of in-situ internal interlayer cracks, which has the advantage of not only releasing the residual thermal stress caused by thermal expansion mismatch, but also releasing the aging residual thermal stress. In addition, compared with through cracks, interlayer cracks make it difficult for heat flow to diffuse directly to the substrate surface through cracks. Therefore, the in-situ internal interlayer crack shell-like structure proposed by the present invention can effectively solve the problem of YSZ thick thermal barrier coating with high temperature resistance, high thermal insulation and long life.

[0139] The YSZ thick thermal barrier coating with in-situ endogenous interlayer cracks and shell-like structure provided by the present invention and its preparation method effectively solve the difficult problem of YSZ thick thermal barrier coating with high temperature resistance, high thermal insulation and long service life. Compared with the YSZ thick thermal barrier coating with traditional structure, the YSZ thick thermal barrier coating with shell-like structure designed by the present invention has the characteristics of forming in-situ endogenous interlayers instead of through cracks during high-temperature service, and the crack propagation stops at the interface of "mud-brick". The interlayer cracks formed by the "mud layer" can not only release the residual thermal stress of thermal expansion mismatch generated during the thermal cycle, but also release the aging residual thermal stress generated by YSZ phase change and sintering at high temperature, which is beneficial to improve the thermal cycle life; in addition, compared with through cracks, interlayer cracks can effectively prevent heat flow from directly diffusing through cracks to reach the substrate, which is beneficial to improve the thermal insulation performance of the coating; in addition, the shell-like "mud-brick" unit composed of RMA and YSZ is more resistant to high temperature and thermal shock than a single YSZ "brick layer", and can be used at high temperatures of 1350℃ and above. The shell-like YSZ thick thermal barrier coating prepared by the present invention has good potential application prospects for high-temperature thermal protection of future new-generation aviation engines, heavy-duty gas turbines and hot-end components of hypersonic aircraft.

[0140] In order to further illustrate the present invention, a YSZ composite thermal barrier coating and a preparation method thereof provided by the present invention are described in detail below in combination with examples. However, it should be understood that these examples are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following examples.

[0141] Example 1

[0142] Commercially purchased NiCrAlY alloy powder and YSZ ceramic powder and LaMA ceramic powder synthesized by high temperature solid phase reaction were used. The DZ125 substrate was sandblasted with 36# corundum sand, ultrasonically cleaned with ethanol for 3 minutes and dried with a hair dryer, and then a YSZ thick thermal barrier coating was prepared on the pretreated DZ125 surface by atmospheric plasma spraying technology. The thickness of the NiCrAlY bonding layer is 150μm, and its main spraying parameters are current 650A, argon flow rate 48.0SLPM, hydrogen flow rate 8.0SLPM, carrier gas flow rate 2.6SLPM, spraying distance 100mm and spray gun speed 1000mm / s; the thickness of the YSZ / LaMA imitation shell element is 100μm, and the thickness ratios of the YSZ "brick layer" and the LaMA "mud layer" in the imitation shell element are 1 and 1.5. There are 5 imitation shell elements, that is, the thickness of the stacked ceramic layer is 500μm, and the main spraying parameters of the "mud layer" and "brick layer" are current 600A, argon flow rate 36.0SLPM, hydrogen flow rate 12.0SLPM, carrier gas flow rate 3.2SLPM, spraying distance 100mm and spray gun speed 1000mm / s.

[0143] A traditional YSZ thick thermal barrier coating with a NiCrAlY bonding layer thickness of 150 μm and a YSZ ceramic surface layer thickness of 500 μm was prepared on the pretreated DZ125 surface using the same spraying parameters as a comparison sample.

[0144] Flame burning thermal cycle tests were carried out on the shell-like structure and traditional structure YSZ thick thermal barrier coatings prepared above.

[0145] During the thermal cycle, the coating surface temperature rises to 1350±25℃ within 2 minutes and keeps burning at a constant temperature. When the burning time reaches 6 minutes, the flame leaves the coating surface, and then the back of the substrate is cooled with compressed air for 2 minutes to reduce the coating surface temperature to room temperature. The traditional structure YSZ thick thermal barrier coating fails after 1033 thermal cycles.

[0146] See also Figure 3 , Figure 3 The macroscopic photographs of the YSZ thick thermal barrier coating with a ceramic layer thickness of 500 μm prepared in Example 1 of the present invention after flame burning thermal cycles at 1350±25°C are shown. Among them, (a) is a traditional structure thermal cycle of 1033 times, (b, c) is a shell-like structure thermal cycle of 1200 times, and its elementary thickness is 100 μm. The thickness ratio of the "brick layer" to the "mud layer" is (b) 1 and (c) 1.5.

[0147] like Figure 3As shown in (a), the traditional YSZ thick thermal barrier coating failed after 1033 thermal cycles due to large-scale shedding of the coating. However, the YSZ thick thermal barrier coating with a shell-like structure and a thickness ratio of "brick layer" to "mud layer" of 1 and 1.5 was not observed to have bulging or shedding after 1200 thermal cycles, and the coating remained intact. Figure 3 As shown in (b, c), the thermal cycle life of the shell-like structure YSZ thick thermal barrier coating is >1200 times, which is much higher than that of the traditional structure YSZ thick thermal barrier coating.

[0148] Example 2

[0149] Commercially purchased NiCrAlY alloy powder and YSZ ceramic powder and LaMA ceramic powder synthesized by high temperature solid phase reaction were used. The DZ125 substrate was sandblasted with 36# corundum sand, ultrasonically cleaned with ethanol for 3 minutes and dried with a hair dryer, and then a YSZ thick thermal barrier coating was prepared on the pretreated DZ125 surface by atmospheric plasma spraying technology. The thickness of the NiCrAlY bonding layer is 150μm, and its main spraying parameters are current 650A, argon flow rate 48.0SLPM, hydrogen flow rate 8.0SLPM, carrier gas flow rate 2.6SLPM, spraying distance 100mm and spray gun speed 1000mm / s; the thickness of the YSZ / LaMA imitation shell element is 100μm, and the thickness ratio of the YSZ "brick layer" to the LaMA "mud layer" in the imitation shell element is 1. The number of imitation shell elements is 7 and 9, that is, the thickness of the stacked ceramic layer is 700μm and 900μm respectively. The main spraying parameters of the "mud layer" and "brick layer" are current 600A, argon flow rate 36.0SLPM, hydrogen flow rate 12.0SLPM, carrier gas flow rate 3.2SLPM, spraying distance 100mm and spray gun speed 1000mm / s.

[0150] High temperature flame burning thermal cycle tests were carried out on the two YSZ thick thermal barrier coatings with shell-like structures prepared above, with the ceramic layer thicknesses of 700 μm and 900 μm.

[0151] During the thermal cycle, the coating surface temperature rises to 1350±25℃ within 2 minutes and keeps burning at a constant temperature. When the burning time reaches 6 minutes, the flame leaves the coating surface, and then compressed air is used to cool the back of the substrate for 2 minutes to reduce the coating surface temperature to room temperature. The test is repeated in this cycle.

[0152] Figure 4The macroscopic photograph and SEM photograph of the cross section of the YSZ thick thermal barrier coating with a shell structure prepared in Example 2 of the present invention after 1000 cycles of flame burning heat at 1350±25°C. Among them, a and c are respectively the macroscopic photograph and SEM photograph of the cross section of the coating with a ceramic layer thickness of 700μm, and b and d are respectively the macroscopic photograph and SEM photograph of the cross section of the coating with a ceramic layer thickness of 900μm. (The SEM photographs in the figure are the corresponding high-magnification SEM photographs).

[0153] Figure 4 After 1000 thermal cycles, it can be seen from the macroscopic photos that the coating surfaces of the two samples did not bulge or fall off, and the coatings remained intact. Figure 4 (a, c); From the low-magnification and high-magnification SEM photos of the coating cross section, it can be observed that after 1000 thermal cycles, the thermal barrier coating is well bonded to the DZ125 substrate, the "mud-brick" interface is tightly bonded, the "mud layer" forms in-situ interlayer cracks, and the internal structure of the coating is intact, as shown in Figure 2. Figure 4 As shown in (b,d).

[0154] Obviously, when the thickness of the ceramic layer of the shell-like YSZ thick thermal barrier coating increases from 700μm to 900μm, after the same number of thermal cycles, i.e. 1000 times, there is no obvious damage to the coating, and the appearance, bonding state and internal structure of the coating remain good. This is mainly due to the release of thermal expansion mismatch residual thermal stress and aging residual thermal stress by the in-situ endogenous interlayer cracks, which improves the strain tolerance of the coating.

[0155] Example 3

[0156] Commercially purchased NiCrAlY alloy powder and YSZ ceramic powder and LaMA ceramic powder synthesized by high temperature solid phase reaction were used. The DZ125 substrate was sandblasted with 36# corundum sand, ultrasonically cleaned with ethanol for 3 minutes and dried with a hair dryer, and then a YSZ thick thermal barrier coating was prepared on the pretreated DZ125 surface by atmospheric plasma spraying technology. The thickness of the NiCrAlY bonding layer is 150μm, and its main spraying parameters are current 650A, argon flow rate 48.0SLPM, hydrogen flow rate 8.0SLPM, carrier gas flow rate 2.6SLPM, spraying distance 100mm and spray gun speed 1000mm / s; the thickness of the YSZ / LaMA imitation shell element is 200μm, and the thickness ratio of the YSZ "brick layer" to the LaMA "mud layer" in the imitation shell element is 1.5. There are 4 imitation shell elements, that is, the thickness of the stacked ceramic layer is 800μm, and the main spraying parameters of the "mud layer" and "brick layer" are current 600A, argon flow rate 36.0SLPM, hydrogen flow rate 12.0SLPM, carrier gas flow rate 3.2SLPM, spraying distance 100mm and spray gun speed 1000mm / s. The same spraying process was used to prepare a traditional structure YSZ thick thermal barrier coating with a NiCrAlY bonding layer thickness of 150μm and a YSZ ceramic surface layer thickness of 800μm on the pretreated DZ125 surface as a comparison sample.

[0157] Flame burning thermal cycle tests were carried out on the shell-like structure and traditional structure YSZ thick thermal barrier coatings prepared above.

[0158] During the thermal cycle process, the coating surface temperature rises to 1400±25℃ within 2 minutes and maintains a constant temperature. When the burning time reaches 6 minutes, the flame leaves the coating surface, and then compressed air is used to cool the back of the substrate for 2 minutes to reduce the coating surface temperature to room temperature. The test is repeated in this way until the coating fails. The number of thermal cycles at failure is called the thermal cycle life.

[0159] See also Figure 5 , Figure 5 The macroscopic photos of the YSZ thick thermal barrier coating with a shell-like structure prepared in Example 3 of the present invention after failure in a flame burning thermal cycle at 1400±25°C are shown. (a) is a conventional structure with 838 cycles; (b) is a shell-like structure with 1956 thermal cycles, with a unit thickness of 200 μm and a thickness ratio of "brick layer" to "mud layer" of 1.5.

[0160] Figure 5 In the experiment, the ceramic layer thickness is 800 μm. The thermal cycle life of the YSZ thick thermal barrier coating with the traditional structure is 838 times, while the thermal cycle life of the shell-like structure is 1956 times, which is about 1.33 times longer. The macroscopic photos after thermal cycle failure are shown in Figure 2. Figure 5As shown in (a, b), it indicates that when the shell-like structure YSZ thick thermal barrier coating has a shell-like element thickness of 200 μm, its thermal cycling life is still much higher than that of the traditional structure YSZ thick thermal barrier coating.

[0161] The above embodiments show that the biggest feature of the shell-like structure YSZ thick thermal barrier coating designed and prepared by the present invention is the formation of in-situ endogenous interlayer cracks at high temperatures, which makes the shell-like structure YSZ thick thermal barrier coating have the advantages of high temperature resistance, high thermal insulation and long life compared with traditional structures.

[0162] A novel YSZ thick thermal barrier coating and a preparation method thereof provided by the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including the manufacture and use of any device or system, and the implementation of any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A YSZ composite thermal barrier coating, characterized in that: include: For bonding layer composited on substrate and YSZ ceramic material layer composited on bonding layer and RMgAl 11 O 19 A composite layup in which layers of material are stacked; Wherein, R is one or more of La, Nb, Sm and Gd; The composite laminate has a crack structure therein.

2. The YSZ composite thermal barrier coating according to claim 1, characterized in that: The composite laminate comprises a YSZ ceramic material layer and an RMgAl 11 O 19 A multi-layer structure formed by stacking material layers in sequence; the number of layers of the multi-layer structure is greater than or equal to 2; The bonding layer comprises a metal bonding layer; The composite laminate has a laminated structure of a brick layer and a mud layer; The thickness of the YSZ ceramic material layer is greater than or equal to RMgAl 11 O 19 The thickness of the material layer; The composite thermal barrier coating is a thick thermal barrier coating.

3. The YSZ composite thermal barrier coating according to claim 2, characterized in that: The material of the bonding layer includes MCrAlY; wherein M is Ni and / or Co; The YSZ ceramic material layer is a brick layer; The RMgAl 11 O 19 The material layer is a mud layer; The YSZ ceramic material layer and RMgAl 11 O 19 The thickness ratio of the material layer is (1-1.5):1; The crack is specifically a longitudinal crack in the relative thickness direction; The cracks are located in the mud layer.

4. The YSZ composite thermal barrier coating according to claim 2, characterized in that: The cracks are specifically longitudinal interlayer cracks generated in situ in the mud layer; The propagation of the longitudinal interlayer crack stops at the interface between the mud layer and the brick layer; The thickness of the bonding layer is 100 to 200 μm; Single YSZ ceramic material layer and RMgAl 11 O 19 The thickness of the brick-mud elementary laminate formed by stacking the material layers is 50 to 200 μm; The thickness of the YSZ composite thermal barrier coating is 500-1500 μm; The YSZ composite thermal barrier coating is specifically a YSZ thick thermal barrier coating with a shell-like structure.

5. A method for preparing a YSZ composite thermal barrier coating, characterized in that: The following steps are involved: 1) Adopting atmospheric plasma spraying method to deposit bonding layer material powder on the substrate to obtain a bonding layer; 2) Using atmospheric plasma spraying, YSZ ceramic material powder and RMgAl 11 O 19 Material powders are sequentially deposited on the bonding layer to form a brick-mud element stack; Wherein, R is one or more of La, Nb, Sm and Gd; 3) Repeat step 2) to form a composite laminate in which multiple brick-mud elementary laminates are deposited in sequence to obtain a YSZ composite thermal barrier coating.

6. The preparation method according to claim 5, characterized in that: The bonding layer material includes MCrAlY; wherein M is Ni and / or Co; The particle size of the bonding layer material powder is -130+325 mesh; The substrate is specifically a pretreated substrate; The pretreatment includes one or more steps of sandblasting, ultrasonic cleaning and drying.

7. The preparation method according to claim 5, characterized in that: In the step 1), the spraying current of the atmospheric plasma spraying is 600-700A; The argon gas flow rate of the atmospheric plasma spraying is 45-50 SLPM; The hydrogen flow rate of the atmospheric plasma spraying is 6 to 10 SLPM; The carrier gas flow rate of the atmospheric plasma spraying is 2.5-3.0 SLPM; The spraying distance of the atmospheric plasma spraying is 90 to 110 mm; The spray gun speed of the atmospheric plasma spraying is 950-1050 mm / s.

8. The preparation method according to claim 5, characterized in that: The particle size of the YSZ ceramic material powder is -200+325 mesh; The RMgAl 11 O 19 The particle size of the material powder is -130+325 mesh; The RMgAl 11 O 19 The material powder is specifically RMgAl 11 O 19 , a mixed powder of ammonium citrate and gum arabic; The RMgAl 11 O 19 , ammonium citrate and gum arabic is 100:(0.6~1.0):(1.8~2.2).

9. The preparation method according to claim 8, characterized in that: The RMgAl 11 O 19 The material powder is prepared by the following steps: a) The RE2O3, MgO and Al2O3 powders are ball-milled to obtain a slurry, which is then dried and crushed, and then subjected to a solid phase reaction to obtain RMgAl 11 O 19 ; The temperature of the solid phase reaction is 1550-1600°C; The solid phase reaction time is 10 to 15 hours; b) RMgAl obtained by the above steps 11 O 19 , ammonium citrate, gum arabic and water are mixed to obtain a mixed slurry, which is then spray granulated to obtain RMgAl 11 O 19 Material powder.

10. The preparation method according to claim 8, characterized in that: In the step 2), the spraying current of the atmospheric plasma spraying is 550-650A; The argon gas flow rate of the atmospheric plasma spraying is 33-38 SLPM; The hydrogen flow rate of the atmospheric plasma spraying is 10-14 SLPM; The carrier gas flow rate of the atmospheric plasma spraying is 3.0-3.5 SLPM; The spraying distance of the atmospheric plasma spraying is 96 to 110 mm; The spray gun speed of the atmospheric plasma spraying is 950-1050 mm / s.

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