Spraying test piece tool, coating spraying method of spraying test piece and nondestructive stripping method of target coating

Abstract

The invention discloses a spraying test piece tool, a coating spraying method of a spraying test piece and a lossless stripping method of a target coating, belongs to the technical field of thermal barrier coating spraying, and aims to solve the technical problem that in the prior art, when a thermal barrier coating is sprayed with a test piece, the target coating is difficult to strip in a lossless mode or difficult to strip in a lossless mode. The spraying device comprises a fixing plate, a protective cover plate arranged on the upper end face of the fixing plate and a plurality of spraying units. A plurality of limiting grooves are formed in the protective cover plate, and the multiple spraying units are movably arranged in the limiting grooves; a plurality of fixing rods are arranged in the fixing plate in a penetrating mode and used for fixing the spraying units. Through reasonable arrangement of the coating structure, nondestructive stripping of the target coating can be realized, the process is simple, and the cost is controllable.

Description

Technical Field

[0001] The invention relates to the technical field of thermal barrier coating spraying, and in particular to a spraying test piece tooling, a coating spraying method for a spraying test piece, and a non-destructive stripping method for a target coating. Background Art

[0002] Applying a thermal protection coating with excellent heat insulation properties on the surface of the aircraft metal substrate can effectively prevent the oxidation, ablation, and impact damage of the base metal, thereby significantly improving the service life of the components. Thermal barrier coating is a typical thermal insulation coating, which is widely used as a high-temperature protective coating to improve the durability and performance of gas turbines, aircraft engines, etc.

[0003] The technology of preparing thermal barrier coatings by thermal spraying has become mature both at home and abroad. However, since the thermal spraying process is a special process, the quality control of the process is relatively difficult. A large number of preliminary experiments and performance tests are required to determine the appropriate process parameters. In engineering applications, it is impossible to perform all relevant performance tests on complex structural parts after spraying. At the same time, in order to save manufacturing and testing costs, before spraying the structural parts, it is usually necessary to use spray test pieces to perform performance tests on the coating.

[0004] The product can be sprayed only after the spray test piece meets the performance requirements to ensure its performance stability. In order to accurately test the performance of the thermal insulation layer in the coating and eliminate the influence of the substrate, bonding layer, etc. on the target test layer, it is necessary to achieve non-destructive peeling of the target layer after spraying and conduct targeted performance tests on the target layer, including porosity, thermal conductivity, etc.

[0005] The thermal barrier coating insulation layer that is widely used at present is usually made of ceramic materials. Ceramic materials have high hardness and poor plasticity. In addition, since the coating cannot withstand the thermal stress of ultra-high temperature and wide temperature range during the spraying process, it is easy to cause problems such as coating peeling. The ceramic layer has certain thickness requirements, ranging from about 0.2mm to 0.9mm. These characteristics make it difficult to achieve non-destructive peeling of the ceramic layer after spraying.

[0006] Therefore, there is an urgent need for a non-destructive stripping method for the target coating in thermal barrier coatings. Summary of the invention

[0007] The purpose of the present invention is to provide a spray test piece tool, a coating spraying method for a spray test piece and a non-destructive stripping method of a target coating, so as to solve the technical problem that non-destructive stripping of a target coating is difficult or difficult to achieve when spraying a thermal barrier coating on a test piece in the prior art.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] The present invention provides a spray test piece tool, comprising a fixed plate, a protective cover plate arranged on the upper surface of the fixed plate, and a plurality of spray units;

[0010] The protective cover plate is provided with a plurality of limiting grooves, and the plurality of spraying units can be movably arranged in the limiting grooves;

[0011] A plurality of fixing rods are inserted into the fixing plate, and the fixing rods are used to fix the spraying unit.

[0012] By arranging multiple spray units on the fixed plate, multiple spray units can be operated simultaneously, so that multiple groups of spray test pieces can be sprayed at the same time; by opening multiple limit grooves on the protective cover plate, the operator can choose the arrangement of the spray units according to actual work needs.

[0013] Optionally or preferably, the spray unit includes a fixing portion and a substrate;

[0014] The fixing portion is an annular structure, and the fixing rod passes through the annular structure and is fixed to the side wall of the fixing plate.

[0015] In the present invention, the operator can select different spraying substrates by selecting the substrate form on the spraying unit to obtain different target stripping coatings.

[0016] A coating spraying method for a spray test piece comprises the following steps:

[0017] S1, surface pretreatment, pretreatment of the spray unit to obtain a clean spray surface;

[0018] S2, spraying a metal bonding layer, spraying on the surface of the substrate to form a metal bonding layer;

[0019] S3, spraying a transition layer, spraying on the surface of the metal bonding layer to form a transition layer;

[0020] S4, spraying a target peeling layer, spraying on the surface of the transition layer to form a target peeling layer.

[0021] Optionally or preferably, the method for pre-treating the spraying unit in step S1 comprises the following steps:

[0022] S11, surface cleaning, placing multiple spray units in acetone and ethanol solutions in turn for ultrasonic cleaning, and drying after cleaning to remove oil stains and impurities on the surface of the spray units;

[0023] S12, installing the spraying unit, fixing the multiple spraying units by fixing rods and installing protective cover plates;

[0024] S13, surface sandblasting, the surface of the substrate in the spraying unit is sandblasted, the sandblasting pressure is 0.2MPa-0.6MPa, the sandblasting distance is 50mm-150mm, the sandblasting time is 4min-6min, and the sandblasting material is corundum sand; after the sandblasting is completed, the residual sandblasting material on the surface is cleaned to obtain a clean spraying surface.

[0025] Optionally or preferably, the method for pre-treating the spraying unit in step S1 further comprises the following steps:

[0026] S14, preheating treatment, preheating the tooling or spraying unit, using a plasma spray gun to directly preheat the surface of the tooling or spraying unit;

[0027] The spraying gas is argon and hydrogen, wherein the flow rate of argon is 50L / min-60L / min, and the flow rate of hydrogen is 3L / min-5L / min; the preheating distance is 100mm-120mm, the preheating temperature is 70℃-100℃, and the cycle is at least twice.

[0028] Optionally or preferably, the spraying method of the metal bonding layer in step S2 is: spraying by atmospheric plasma spraying process, the spraying material is NiCrAlY powder and / or CoCrAlY powder and / or CoNiCrAlY powder;

[0029] The spraying gas is argon and hydrogen, where the flow rate of argon is 50L / min-60L / min, and the flow rate of hydrogen is 3L / min-5L / min;

[0030] During the spraying process, the current is 560A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 25g / min-35g / min;

[0031] The number of spraying cycles was 5 times, and the spraying thickness was 100 μm-120 μm.

[0032] Optionally or preferably, the spraying method of the transition layer in S3 is: spraying by atmospheric plasma spraying process, the spraying material is special NaCl powder;

[0033] The spraying gas is argon and hydrogen, where the flow rate of argon is 50L / min-60L / min, and the flow rate of hydrogen is 3L / min-5L / min;

[0034] During the spraying process, the current is 560A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 10g / min-15g / min;

[0035] The number of spraying cycles is 10 times, and the spraying thickness is 80 μm-100 μm.

[0036] Optionally or preferably, a method for preparing a special NaCl powder comprises the following steps:

[0037] S31, placing analytical pure NaCl powder in a ball mill, and dry grinding the NaCl powder with a ball-to-material ratio of 1:1 and a rotation speed of 400 rpm for 10 h to 12 h until the particle size of the NaCl powder is less than or equal to 150 μm;

[0038] S32, drying the ground NaCl powder at a temperature of 60° C. for 2 h.

[0039] Optionally or preferably, the spraying method of the target peeling layer in S4 is: spraying by atmospheric plasma spraying process, the spraying material is ceramic spraying powder;

[0040] The spraying gas is argon and hydrogen, with the flow rate of argon being 35L / min-40L / min and the flow rate of hydrogen being 9L / min-12L / min;

[0041] During the spraying process, the current is 550A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 15g / min-25g / min;

[0042] The number of spraying cycles was 8 times, and the spraying thickness was 180 μm-200 μm.

[0043] A method for non-destructive stripping of a target coating, characterized in that the target coating obtained by the coating spraying method according to any one of claims 3 to 9 is subjected to non-destructive stripping, wherein the method comprises:

[0044] After cooling to room temperature, the spray unit is removed from the fixed plate and placed in deionized water for ultrasonic vibration for 30s-50s until the transition layer is dissolved to obtain the target coating after stripping;

[0045] The target coating after stripping is cleaned and dried to complete the non-destructive stripping of the target coating.

[0046] Based on the above technical solution, the present invention can at least produce the following technical effects:

[0047] The spray test piece tooling provided by the present invention can simultaneously operate multiple spray units by simultaneously arranging multiple spray units on a fixed plate, thereby being able to simultaneously perform multiple groups of spray test piece operations; in addition, operators can select different arrangements of the spray units and select different types of substrates according to actual work needs.

[0048] The coating spraying method of the spray test piece provided by the present invention sprays a transition layer between the metal bonding layer and the target peeling layer, and the transition layer spray material is selected as NaCl powder, which has strong chemical stability and can be quickly dissolved in water, so as to obtain the target peeling coating without damage;

[0049] The non-destructive stripping method of the target coating provided by the present invention is to place the spraying unit after spraying in deionized water, and the deionized water penetrates into the transition layer through the ceramic pores of the target stripping layer, and the transition layer is quickly dissolved after being decomposed by water, thereby achieving automatic stripping. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The overall structure of the spray test piece tooling of the present invention is shown in FIG. Figure 1 ;

[0051] Figure 2 The overall structure of the spray test piece tooling of the present invention is shown in FIG. Figure 2 (protective cover omitted);

[0052] Figure 3 It is a schematic diagram of the connection relationship between the spray unit and the fixing rod in the spray test piece tooling of the present invention;

[0053] Figure 4 is a flow chart of a coating spraying method for spraying a test piece of the present invention;

[0054] Figure 5 It is a surface state diagram of the transition layer in the coating spraying method of the spray test piece of the present invention;

[0055] Figure 6 is a surface state diagram of a target coating before stripping in a non-destructive stripping method of a target coating of the present invention;

[0056] Figure 7 It is a surface state diagram of the target coating after stripping in the non-destructive stripping method of the target coating of the present invention.

[0057] In the figure: 10, spray unit; 11, fixing part; 12, base plate; 20, protective cover plate; 21, limiting groove; 30, fixing plate; 31, fixing rod. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work belong to the scope of protection of the present invention.

[0059] Embodiment 1:

[0060] See also Figures 1 to 3 A spray test piece tooling includes a protective cover plate 20, a fixing plate 30 and a receiving plate arranged in sequence from top to bottom; a plurality of spray units 10 are movably fixed on the fixing plate 30 and fixed by a fixing rod 31.

[0061] Specifically, the spray unit 10 includes an annular fixing portion 11 and a base plate 12 fixedly connected to the fixing portion 11; the fixing rod 31 sequentially passes through the annular fixing portions 11 of multiple spray units 10 and is fixed to the side wall of the fixing plate 30 through a locking nut.

[0062] In this embodiment, a protective cover plate 20 is fixed to the upper end surface of the fixed plate 30, and a plurality of limiting grooves 21 are provided on the protective cover plate 20 and the fixed plate 30. The above-mentioned multiple spray units 10 can be movably arranged in the limiting grooves 21, and the operator can select the arrangement method of the spray unit 10 in the limiting grooves 21 or the opening method of the limiting grooves 21 according to actual work needs.

[0063] It is worth noting that the operator can also select different substrates 12 according to actual work needs.

[0064] Embodiment 2

[0065] See also Figure 4 This embodiment provides a coating spraying method for a spray test piece, which is based on the spray test piece tooling provided in Example 1 to spray the test piece, including the following steps:

[0066] S1, surface pretreatment, pretreatment of the spray unit 10 to obtain a clean spray surface;

[0067] In this embodiment, the surface pretreatment method specifically includes the following steps:

[0068] S11, surface cleaning, placing multiple spray units 10 in acetone and ethanol solutions in turn for ultrasonic cleaning, and drying after cleaning to remove oil stains and impurities on the surface of the spray units 10;

[0069] S12, installing the spraying unit 10, fixing the multiple spraying units 10 through the fixing rod 31 and installing the protective cover plate 20;

[0070] S13, surface sandblasting, the surface of the substrate 12 in the spraying unit 10 is sandblasted, the sandblasting pressure is 0.2MPa-0.6MPa, the sandblasting distance is 50mm-150mm, the sandblasting time is 4min-6min, and the sandblasting material is corundum sand; after the sandblasting is completed, the residual sandblasting material on the surface is cleaned to obtain a clean spraying surface.

[0071] In addition, in order to reduce the thermal stress caused by the sudden change in temperature during spraying, in this embodiment, before spraying the metal bonding layer, the spraying unit 10 or the substrate 12 needs to be preheated to improve the surface quality of the coating, specifically, including:

[0072] S14, preheating treatment, preheating the tooling or spraying unit 10;

[0073] In this embodiment, the specific method of preheating treatment is: using a plasma spray gun to directly preheat the surface of the tooling or spraying unit 10;

[0074] The spraying gas is argon and hydrogen, wherein the flow rate of argon is 50L / min-60L / min, and the flow rate of hydrogen is 3L / min-5L / min; the preheating distance is 100mm-120mm, the preheating temperature is 70℃-100℃, and the cycle is repeated twice.

[0075] S2, spraying a metal bonding layer, spraying on the surface of the substrate 12 to form a metal bonding layer;

[0076] In this embodiment, the method for spraying the metal bonding layer is: using an atmospheric plasma spraying process for spraying, the spray material is NiCrAlY powder and / or CoCrAlY powder and / or CoNiCrAlY powder; the spraying gas is argon and hydrogen, wherein the flow rate of argon is 50L / min-60L / min, and the flow rate of hydrogen is 3L / min-5L / min; during the spraying process, the current is 560A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 25g / min-35g / min; the number of spraying cycles is 5 times, and the spraying thickness is 100μm-120μm.

[0077] S3, spraying a transition layer, spraying on the surface of the metal bonding layer to form a transition layer;

[0078] In this embodiment, the method of spraying the transition layer is: using atmospheric plasma spraying process for spraying, the spray material is special NaCl powder; NaCl has stable properties, is not easy to react with other substances, and can maintain good chemical stability at high temperature, has high safety, low cost, and is very soluble in water. As a transition layer of thermal barrier coating, it will not react with the thermal insulation ceramic layer, ensuring its original coating performance. At the same time, due to the structural characteristics of the thermal spray coating, there are certain pores inside the ceramic layer. After being placed in water, water can penetrate into the NaCl transition layer through the pores, so that NaCl directly contacts with water and can be quickly dissolved, achieving non-destructive stripping of the target layer, which is a more suitable transition stripping material.

[0079] The spraying gases are argon and hydrogen, with the argon flow rate being 50L / min-60L / min and the hydrogen flow rate being 3L / min-5L / min; during the spraying process, the current is 560A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 10g / min-15g / min; the number of spraying cycles is 10 times, and the spraying thickness is 80μm-100μm.

[0080] The method for preparing the above-mentioned special NaCl powder comprises the following steps:

[0081] S31, placing analytical pure NaCl powder in a ball mill, and dry grinding the NaCl powder with a ball-to-material ratio of 1:1 and a rotation speed of 400 rpm for 10 h to 12 h until the particle size of the NaCl powder is less than or equal to 150 μm;

[0082] S32, drying the ground NaCl powder at a temperature of 60° C. for 2 h.

[0083] It should be noted that after the NaCl transition layer is sprayed, due to its large particle size, the surface roughness after spraying is relatively high. In order not to affect the performance of the ceramic layer, 2000# sandpaper is used to lightly polish the surface to reduce the surface roughness.

[0084] S4, spraying a target peeling layer, spraying on the surface of the transition layer to form a target peeling layer.

[0085] In this embodiment, the method for spraying the target peeling layer is: using atmospheric plasma spraying process for spraying, the spray material is ceramic spray powder; the spraying gas is argon and hydrogen, wherein the flow rate of argon is 35L / min-40L / min, and the flow rate of hydrogen is 9L / min-12L / min; during the spraying process, the current is 550A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 15g / min-25g / min; the number of spraying cycles is 8 times, and the spraying thickness is 180μm-200μm.

[0086] Embodiment 3

[0087] See also Figures 5 to 7 A non-destructive stripping method for a target coating is provided, and is used to achieve non-destructive stripping of the target stripping layer in Example 2. Specifically, after the coating is cooled to room temperature, the spray unit 10 is removed from the fixed plate 30, and is placed in deionized water for ultrasonic vibration for 30s-50s until the transition layer is dissolved, thereby obtaining the target coating after stripping; then, the stripped ceramic layer is ultrasonically cleaned with deionized water and ethanol, and then placed in a 60°C oven for drying for two hours, thereby completing the non-destructive stripping of the target ceramic layer, and finally obtaining a ceramic layer specimen of a fixed size for performance testing.

[0088] In addition, the tooling provided in Example 1 is also placed in deionized water and ethanol for ultrasonic cleaning to remove the residual coating, and finally dried for next use.

[0089] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0090] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A spray test piece tool, characterized in that: It comprises a fixing plate (30), a protective cover plate (20) arranged on the upper end surface of the fixing plate (10), and a plurality of spraying units (10); The protective cover plate (20) is provided with a plurality of limiting grooves (21), and a plurality of the spraying units (10) can be movably arranged in the limiting grooves (21); A plurality of fixing rods (31) are inserted into the fixing plate (30), and the fixing rods (31) are used to fix the spraying unit (10).

2. The spray test piece tooling according to claim 1, characterized in that: The spraying unit (10) comprises a fixing portion (11) and a base plate (12); The fixing portion (11) is an annular structure, and the fixing rod (31) passes through the annular structure and is fixed to the side wall of the fixing plate (30).

3. A coating spraying method for a spray test piece, characterized in that: The spraying test piece tooling according to any one of claims 1 to 2 is used to spray the test piece, comprising the following steps: S1, surface pretreatment, pretreatment of the spray unit (10) to obtain a clean spray surface; S2, spraying a metal bonding layer, spraying on the surface of the substrate (12) to form a metal bonding layer; S3, spraying a transition layer, spraying on the surface of the metal bonding layer to form a transition layer; S4, spraying a target peeling layer, spraying on the surface of the transition layer to form a target peeling layer.

4. The coating spraying method for a spray test piece according to claim 3, characterized in that: The method for pre-treating the spraying unit (10) in step S1 comprises the following steps: S11, surface cleaning, placing the plurality of spray units (10) in acetone and ethanol solutions in turn for ultrasonic cleaning, and drying after cleaning to remove oil stains and impurities on the surface of the spray units (10); S12, installing the spraying unit (10), fixing the plurality of spraying units (10) via the fixing rod (31) and installing the protective cover plate (20); S13, surface sandblasting, sandblasting the surface of the substrate (12) in the spraying unit (10), the sandblasting pressure is 0.2MPa-0.6MPa, the sandblasting distance is 50mm-150mm, the sandblasting time is 4min-6min, and the sandblasting material is corundum sand; after the sandblasting is completed, the residual sandblasting material on the surface is cleaned to obtain a clean spraying surface.

5. The coating spraying method for a spray test piece according to claim 4, characterized in that: The method for pre-treating the spraying unit (10) in step S1 further comprises the following steps: S14, preheating treatment, preheating the tooling or the spraying unit (10), using a plasma spray gun to directly preheat the surface of the tooling or the spraying unit (10); The spraying gas is argon and hydrogen, wherein the flow rate of argon is 50L / min-60L / min, and the flow rate of hydrogen is 3L / min-5L / min; the preheating distance is 100mm-120mm, the preheating temperature is 70℃-100℃, and the cycle is at least twice.

6. The coating spraying method for a spray test piece according to claim 3, characterized in that: The spraying method of the metal bonding layer in step S2 is: spraying by atmospheric plasma spraying process, and the spraying material is NiCrAlY powder and / or CoCrAlY powder and / or CoNiCrAlY powder; The spraying gas is argon and hydrogen, where the flow rate of argon is 50L / min-60L / min, and the flow rate of hydrogen is 3L / min-5L / min; During the spraying process, the current is 560A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 25g / min-35g / min; The number of spraying cycles was 5 times, and the spraying thickness was 100 μm-120 μm.

7. The coating spraying method for a spray test piece according to claim 3, characterized in that: The spraying method of the transition layer in S3 is: spraying by atmospheric plasma spraying process, and the spraying material is special NaCl powder; The spraying gas is argon and hydrogen, where the flow rate of argon is 50L / min-60L / min, and the flow rate of hydrogen is 3L / min-5L / min; During the spraying process, the current is 560A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 10g / min-15g / min; The spraying cycle number is 10 times, and the spraying thickness is 80 μm-100 μm.

8. The coating spraying method for a spray test piece according to claim 7, characterized in that: The method for preparing the special NaCl powder comprises the following steps: S31, placing analytical pure NaCl powder in a ball mill, and dry grinding the NaCl powder with a ball-to-material ratio of 1:1 and a rotation speed of 400 rpm for 10 h to 12 h until the particle size of the NaCl powder is less than or equal to 150 μm; S32, drying the ground NaCl powder at a temperature of 60° C. for 2 h.

9. The coating spraying method for a spray test piece according to claim 3, characterized in that: The spraying method of the target peeling layer in S4 is: spraying by atmospheric plasma spraying process, and the spraying material is ceramic spraying powder; The spraying gas is argon and hydrogen, with the flow rate of argon being 35L / min-40L / min and the flow rate of hydrogen being 9L / min-12L / min; During the spraying process, the current is 550A-600A, the spraying distance is 100mm-120mm, and the powder feeding rate is 15g / min-25g / min; The number of spraying cycles was 8 times, and the spraying thickness was 180 μm-200 μm.

10. A non-destructive stripping method for a target coating, characterized in that: The target coating obtained by the coating spraying method according to any one of claims 3 to 9 is subjected to non-destructive stripping, wherein the method comprises: After cooling to room temperature, the spray unit (10) is removed from the fixed plate (30), and placed in deionized water for ultrasonic vibration for 30s-50s until the transition layer is dissolved, thereby obtaining a target coating after stripping; The target coating after stripping is cleaned and dried to complete the non-destructive stripping of the target coating.

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