A suspension plasma spraying slurry and its preparation method and application

Abstract

The present invention discloses a suspension plasma spraying slurry and a preparation method and application thereof, and relates to the field of plasma etching resistant ceramic coatings. The method comprises the following steps: S1, pre-treating the substrate; S2, heat-treating the pre-treated substrate; S3, spraying the pre-treated spraying slurry with APS to the substrate surface treated by S2; S4, spraying the pre-treated spraying slurry with SPS to the coating surface obtained by S3; wherein, the pre-treated spraying slurry in S4, the pre-treatment method comprises: stirring the spraying slurry and heating it to 173-190°C, maintaining it for 10-30min, and continuing to heat it to 220-240°C, and maintaining it for 10-30min. The present invention further improves the bonding strength of the yttrium oxide coating, reduces the porosity and surface roughness, and the obtained coating has excellent properties by performing multiple specific pre-treatment or heat treatment steps on the substrate surface, the spraying slurry and the coating.

Description

Technical Field

[0001] The invention provides a suspension plasma spraying slurry and a preparation method and application thereof, and relates to the field of plasma etching resistant ceramic coatings. Background Art

[0002] The increase in silicon wafer size in electronic manufacturing has brought new requirements to all related processes, including plasma etching of wafers. Yttria exhibits excellent resistance to plasma erosion, so it is often used as a protective cover for plasma etching chambers. The plasma thermal spray (APS) process is often used to apply yttria to the surface that needs protection.

[0003] The plasma thermal spray process uses a high-temperature plasma flame to spray carbides, cermets, ceramics, etc. The powder particle size used in this thermal spray process ranges from 20 microns to 100 microns, so a coarse structure (micrometer-level features) coating is produced. With the increasing demand for fine dimensions in ultra-large-scale integrated circuits, there is a growing interest in depositing coatings with submicron and nanometer-sized features. Compared with traditional coarse structure coatings, fine structure coatings have improved performance in terms of wear, etching resistance, bonding strength, voltage resistance and chemical stability. The use of APS to deposit fine particles still faces great challenges because the powder particles do not have enough momentum to penetrate the viscous plasma plume, and particle agglomeration will lead to poor flow and clogging of the injector nozzle.

[0004] An emerging technology that alleviates the problem of feeding nano or submicron powders is the suspension plasma spray (SPS) technique, which involves feeding fine powders in the form of a suspension in a suitable liquid medium (aqueous or organic solvent). Coatings produced by suspension atmospheric pressure plasma spraying are composed of finer fragments or particles than their counterparts using conventional plasma spraying, and the produced coatings generally show a denser microstructure, showing great potential in producing coatings with high density, low porosity, and greater resistance to plasma etching. However, the SPS method has a low powder loading rate and takes a lot of time to prepare a coating of ideal thickness. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a suspension plasma spray slurry used in conjunction with a specific coating preparation method and its preparation method and application. The slurry is used in conjunction with a specific coating preparation method, and the prepared coating has the characteristics of low roughness and etching resistance. The specific scheme is as follows:

[0006] A suspension plasma spraying slurry comprises yttrium oxide and purified water, wherein the purity of the yttrium oxide is ≥99.9%, the particle size is 1-9 μm, and the mass of the yttrium oxide accounts for 20-30wt% of the sum of the mass of the yttrium oxide and the purified water; the slurry also comprises one or more of a dispersant and a defoamer.

[0007] Preferably, the dispersant includes one or more of ammonium polyacrylate, polyacrylic acid, polyethylene glycol, phosphate, isooctyl polyoxyethylene ether, BYK-199 modified benzene, DOLAPIX CE 64, BYK-154, and the mass fraction in the slurry is 0.01wt%-2.50wt%.

[0008] Preferably, the defoaming agent includes one or two of BYK-016 and BYK-012, and the mass fraction in the slurry is 0.05wt%-2.00wt%.

[0009] A method for preparing the above suspension plasma spraying slurry comprises the following steps:

[0010] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0011] (2) heat treating the obtained slurry;

[0012] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0013] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0014] Preferably, the components in step (1) are calculated according to the above suspension plasma spraying slurry formula.

[0015] Preferably, in step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:(1-2):(0.1-0.3).

[0016] Preferably, in the ball milling of step (1), the ball mill speed is 500-700 rpm and the ball milling time is 4-8 h.

[0017] Preferably, in step (2), the heat treatment is first heated to 60-80°C, maintained for 1-2 hours, then heated to 150-170°C, maintained for 3-5 hours, and then naturally cooled to room temperature.

[0018] Preferably, the ultrasonic dispersion in step (3) is performed for 10-30 minutes.

[0019] Preferably, in the secondary ball milling in step (4), the ball mill speed is 200-300 rpm and the ball milling time is 2-3 h.

[0020] An application of the above suspension plasma spraying slurry in preparing a low-roughness, etch-resistant Y2O3 coating comprises the following steps:

[0021] S1. Pre-treating the substrate;

[0022] S2, heat treating the pre-treated substrate;

[0023] S3, spraying the pretreated spray powder onto the substrate surface treated in S2 using APS;

[0024] S4, spraying the pretreated spray slurry onto the coating surface obtained in S3 using SPS;

[0025] The pretreatment method of the spray slurry after pretreatment in S4 includes: stirring the spray slurry and heating it to 173-190° C., maintaining it for 10-30 minutes, and continuing to heat it to 220-240° C., and maintaining it for 10-30 minutes.

[0026] Preferably, the pretreatment method of the spray slurry after the pretreatment in S4 includes: stirring the spray slurry and heating it to 173-180°C, maintaining it for 10-20 minutes, and continuing to heat it to 220-227°C, and maintaining it for 10-20 minutes.

[0027] Preferably, the pretreatment method of the spray powder after pretreatment in S3 includes: mixing yttrium oxide and polyethylene glycol and heating to 80-100°C, maintaining for 10-20 minutes, heating to 135-140°C, maintaining for 10-20 minutes, and completely removing the liquid to obtain the resulting powder for use; wherein the mass ratio of yttrium oxide to polyethylene glycol is (20-25):1.

[0028] The above preparation method further comprises: S5, heat treating the coating obtained in S4.

[0029] Preferably, the coating obtained in S4 is subjected to heat treatment, including treatment at 300-380° C. for 1-2 hours, and cooling to 200-270° C. for 3-5 hours.

[0030] Preferably, in S3, APS is sprayed with a thickness of 150-250 μm.

[0031] Preferably, SPS is used for spraying in S4, and the spraying thickness is 40-80 μm.

[0032] Preferably, the pre-treatment in S1 includes treating the average surface roughness of the substrate to 5.0-7.0 μm.

[0033] Preferably, in the heat treatment of S2, the substrate is heated to 450-480° C. and then cooled to 270-300° C. After testing, the bonding strength of the coating obtained by this heat treatment method is significantly higher than that obtained by direct preheating to 270-300° C.

[0034] The spraying slurry described in S4 includes yttrium oxide, a solvent, and a dispersant.

[0035] Preferably, the yttrium oxide is made of high-purity yttrium oxide powder with a particle size of 1-9 um, and the addition percentage of the powder is 20wt%-40wt%.

[0036] Preferably, the solvent is pure water; the dispersant includes one or more of ammonium polyacrylate, polyacrylic acid, polyethylene glycol, phosphate, isooctyl polyoxyethylene ether, BYK-199 modified benzene, DOLAPIX CE 64, BYK-154, and the added amount is 0.01wt%-2.00wt%.

[0037] Preferably, the spraying slurry further includes a defoamer, and the defoamer includes BYK-012 or BYK-16, and the added amount is 0.05wt%-2.00wt%.

[0038] Preferably, the spraying parameters used in the atmospheric plasma spraying (APS) are: current of 600-800A, powder feeding speed of 5-30g / min, spraying distance of 100-300mm, argon flow rate of 35-65NLPM, and hydrogen flow rate of 5-15NLPM.

[0039] Preferably, the spraying parameters used for the suspension plasma spraying (SPS) are: voltage 50-80V, current 500-800A, suspension injection plasma jet 40-70g / min, suspension injection plasma jet incident angle 50-90°, main gas flow 35-75NLPM, spraying distance 40-100mm, and spray gun moving speed 500-1500mm / s.

[0040] Preferably, the heat treatment of the present invention adopts plasma jet air spraying.

[0041] Preferably, the main gas is argon with a purity of 99.999%.

[0042] Beneficial effects of the present invention:

[0043] The present invention pre-treats the yttrium oxide powder used in the slurry so that when the slurry is used to prepare the yttrium oxide coating, a denser coating can be formed, and lower roughness and higher etching resistance can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Example 1 in the performance testing step;

[0045] Figure 2 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Example 2 in the performance testing step;

[0046] Figure 3 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Example 3 in the performance testing step;

[0047] Figure 4 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Example 4 in the performance testing step;

[0048] Figure 5 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Comparative Example 1 in the performance testing step;

[0049] Figure 6 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Comparative Example 2 in the performance testing step;

[0050] Figure 7 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Comparative Example 3 in the performance testing step;

[0051] Figure 8 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Comparative Example 4 in the performance testing step;

[0052] Fig. 9 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Comparative Example 5 in the performance testing step;

[0053] Fig.10 This is an electron microscope image of the coating obtained by preparing the slurry obtained in Comparative Example 6 in the performance testing step;

[0054] Fig.11 This is an electron micrograph of the coating obtained by preparing the slurry obtained in Comparative Example 7 in the performance testing step. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0056] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0057] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified. The yttrium oxide powder used in the following examples has a D50 of 2.74.

[0058] Example 1 Preparation of suspension plasma spraying slurry:

[0059] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant ammonium polyacrylate, the mass fraction of which in the slurry is 0.50wt%; defoamer BYK-016, the mass fraction of which in the slurry is 0.5wt%.

[0060] Preparation process:

[0061] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0062] (2) heat treating the obtained slurry;

[0063] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0064] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0065] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:1:0.1.

[0066] In the ball milling of step (1), the ball mill speed is 500 rpm and the ball milling time is 4 h.

[0067] In step (2), the heat treatment is first heated to 60°C, maintained for 1 hour, then heated to 150°C, maintained for 3 hours, and then naturally cooled to room temperature.

[0068] The ultrasonic dispersion in step (3) is carried out for 10 minutes.

[0069] In the secondary ball milling of step (4), the ball mill speed is 200 rpm and the ball milling time is 2 h.

[0070] Example 2 Preparation of suspension plasma spraying slurry:

[0071] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0072] Preparation process:

[0073] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0074] (2) heat treating the obtained slurry;

[0075] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0076] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0077] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:1:0.1.

[0078] In the ball milling of step (1), the ball mill speed is 500 rpm and the ball milling time is 4 h.

[0079] In step (2), the heat treatment is first heated to 60-80°C, maintained for 1 hour, then heated to 150°C, maintained for 3 hours, and then naturally cooled to room temperature.

[0080] The ultrasonic dispersion in step (3) is carried out for 10 minutes.

[0081] In the secondary ball milling of step (4), the ball mill speed is 200 rpm and the ball milling time is 2 h.

[0082] Example 3 Preparation of suspension plasma spraying slurry:

[0083] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant isooctyl alcohol polyoxyethylene ether, the mass fraction of which in the slurry is 2.50wt%; defoamer BYK-016, the mass fraction of which in the slurry is 2.00wt%.

[0084] Preparation process:

[0085] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0086] (2) heat treating the obtained slurry;

[0087] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0088] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0089] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:1:0.1.

[0090] In the ball milling of step (1), the ball mill speed is 500 rpm and the ball milling time is 4 h.

[0091] In step (2), the heat treatment is first heated to 60°C, maintained for 1 hour, then heated to 150°C, maintained for 3 hours, and then naturally cooled to room temperature.

[0092] The ultrasonic dispersion in step (3) is carried out for 10 minutes.

[0093] In the secondary ball milling of step (4), the ball mill speed is 200 rpm and the ball milling time is 2 h.

[0094] Example 4 Preparation of suspension plasma spraying slurry:

[0095] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0096] Preparation process:

[0097] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0098] (2) heat treating the obtained slurry;

[0099] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0100] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0101] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:2:0.3.

[0102] In the ball milling of step (1), the ball mill speed is 700 rpm and the ball milling time is 8 h.

[0103] In step (2), the heat treatment is first heated to 80°C, maintained for 2 hours, then heated to 170°C, maintained for 5 hours, and then naturally cooled to room temperature.

[0104] The ultrasonic dispersion in step (3) is carried out for 30 minutes.

[0105] In the secondary ball milling of step (4), the ball mill speed is 300 rpm and the ball milling time is 3 h.

[0106] Comparative Example 1 Preparation of suspension plasma spraying slurry:

[0107] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0108] Preparation process:

[0109] (1) Mix all the components in the formula and disperse them by ultrasonication;

[0110] (2) The obtained slurry is further ball-milled to obtain a suspension plasma spraying slurry.

[0111] The ultrasonic dispersion time is 30 minutes.

[0112] The ball milling process was performed at a speed of 300 rpm and a ball milling time of 3 h.

[0113] Comparative Example 2 Preparation of suspension plasma spraying slurry:

[0114] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0115] Preparation process:

[0116] (1) adding yttrium oxide powder to water and milling the mixture in a ball mill;

[0117] (2) heat treating the obtained slurry;

[0118] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0119] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0120] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:2.

[0121] In the ball milling of step (1), the ball mill speed is 700 rpm and the ball milling time is 8 h.

[0122] In step (2), the heat treatment is first heated to 80°C, maintained for 2 hours, then heated to 170°C, maintained for 5 hours, and then naturally cooled to room temperature.

[0123] The ultrasonic dispersion in step (3) is carried out for 30 minutes.

[0124] In the secondary ball milling of step (4), the ball mill speed is 300 rpm and the ball milling time is 3 h.

[0125] Comparative Example 3 Preparation of suspension plasma spraying slurry:

[0126] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0127] Preparation process:

[0128] (1) adding yttrium oxide powder to water and isooctyl alcohol polyoxyethylene ether and milling the mixture in a ball mill;

[0129] (2) heat treating the obtained slurry;

[0130] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0131] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0132] In step (1), the mass ratio of yttrium oxide powder, water and isooctyl alcohol polyoxyethylene ether is 1:2:2.

[0133] In the ball milling of step (1), the ball mill speed is 700 rpm and the ball milling time is 8 h.

[0134] In step (2), the heat treatment is first heated to 80°C, maintained for 2 hours, then heated to 170°C, maintained for 5 hours, and then naturally cooled to room temperature.

[0135] The ultrasonic dispersion in step (3) is carried out for 30 minutes.

[0136] In the secondary ball milling of step (4), the ball mill speed is 300 rpm and the ball milling time is 3 h.

[0137] Comparative Example 4 Preparation of suspension plasma spraying slurry:

[0138] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0139] Preparation process:

[0140] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0141] (2) heat treating the obtained slurry;

[0142] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0143] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0144] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:2:2.

[0145] In the ball milling of step (1), the ball mill speed is 700 rpm and the ball milling time is 8 h.

[0146] In step (2), the temperature is raised to 80° C., maintained for 2 h, and then naturally cooled to room temperature.

[0147] The ultrasonic dispersion in step (3) is carried out for 30 minutes.

[0148] In the secondary ball milling of step (4), the ball mill speed is 300 rpm and the ball milling time is 3 h.

[0149] Comparative Example 5 Preparation of suspension plasma spraying slurry:

[0150] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0151] Preparation process:

[0152] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0153] (2) heat treating the obtained slurry;

[0154] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0155] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0156] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:2:2.

[0157] In the ball milling of step (1), the ball mill speed is 700 rpm and the ball milling time is 8 h.

[0158] In step (2), the temperature is raised to 80° C., maintained for 7 h, and then naturally cooled to room temperature.

[0159] The ultrasonic dispersion in step (3) is carried out for 30 minutes.

[0160] In the secondary ball milling of step (4), the ball mill speed is 300 rpm and the ball milling time is 3 h.

[0161] Comparative Example 6 Preparation of suspension plasma spraying slurry:

[0162] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0163] Preparation process:

[0164] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0165] (2) heat treating the obtained slurry;

[0166] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0167] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0168] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:2:2.

[0169] In the ball milling of step (1), the ball mill speed is 700 rpm and the ball milling time is 8 h.

[0170] In step (2), the temperature is raised to 170° C., maintained for 5 h, and then naturally cooled to room temperature.

[0171] The ultrasonic dispersion in step (3) is carried out for 30 minutes.

[0172] In the secondary ball milling of step (4), the ball mill speed is 300 rpm and the ball milling time is 3 h.

[0173] Comparative Example 7 Preparation of suspension plasma spraying slurry:

[0174] Formula: including yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%. The mass of yttrium oxide accounts for 20wt% of the sum of the mass of yttrium oxide and purified water; the slurry also includes dispersant polyacrylic acid, the mass fraction of which in the slurry is 2.00wt%; defoamer BYK-012, the mass fraction of which in the slurry is 1.50wt%.

[0175] Preparation process:

[0176] (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill;

[0177] (2) heat treating the obtained slurry;

[0178] (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication;

[0179] (4) The obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry.

[0180] In step (1), the mass ratio of yttrium oxide powder, water and polyethylene glycol is 1:2:2.

[0181] In the ball milling of step (1), the ball mill speed is 700 rpm and the ball milling time is 8 h.

[0182] In step (2), the temperature is raised to 170° C., maintained for 7 h, and then naturally cooled to room temperature.

[0183] The ultrasonic dispersion in step (3) is carried out for 30 minutes.

[0184] In the secondary ball milling of step (4), the ball mill speed is 300 rpm and the ball milling time is 3 h.

[0185] The slurries obtained in all the above examples and comparative examples were used to prepare low-roughness and etch-resistant Y2O3 coatings:

[0186] The average roughness of the aluminum test piece was 6.58um, and a plasma gun was used for air spray heat treatment before spraying (after heating to 350°C, cooling to 170°C).

[0187] First, use APS to spray a coating with a thickness of 120um. The spraying parameters are: argon powder feeding 3.5NLPM, powder feeding amount 25g / min, current 600A, turntable speed 60n / min, main argon 4.0NLPM, hydrogen 8NLPM, and spray spacing 160mm. (The powder sprayed by APS is prepared by the following method: yttrium oxide and polyethylene glycol are mixed and heated to 100℃, kept for 20min, heated to 140℃, kept for 20min, and the powder obtained after the liquid is completely removed is used for standby; the mass ratio of yttrium oxide to polyethylene glycol is 25:1.)

[0188] Then use SPS to spray the suspension plasma spray slurry and spray a coating with a thickness of 60um. Use the plasma gun to preheat the air spray before spraying. The spraying parameters are: voltage 65V, current 550A, suspension injection plasma jet 65g / min, suspension injection plasma jet incident angle 60°, main gas flow 45NLPM, spraying distance 50mm, and spray gun moving speed 700mm / s.

[0189] The coatings prepared from the slurries obtained in all the above examples and comparative examples were tested for performance, and the results are as follows:

[0190]

[0191] 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.

[0192] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A suspension plasma spraying slurry, characterized in that: The slurry comprises yttrium oxide and purified water, wherein the purity of yttrium oxide is ≥99.9%, the particle size is 1-9 μm, and the mass of yttrium oxide accounts for 20-40wt% of the sum of the mass of yttrium oxide and purified water; the slurry also comprises one or more of a dispersant and a defoamer; the dispersant is ammonium polyacrylate, and the mass fraction in the slurry is 0.50wt%; The preparation method of the suspension plasma spraying slurry comprises the following steps: (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill; (2) heat treating the obtained slurry; (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication; (4) the obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry; the mass ratio of yttrium oxide powder, water and polyethylene glycol in step (1) is 1:(1-2):(0.1-0.3); the heat treatment in step (2) is first heated to 60-80°C, maintained for 1-2h, then heated to 150-170°C, maintained for 3-5h, and naturally cooled to room temperature; Among them, the method of applying the suspension plasma spraying slurry to prepare the low roughness and etch-resistant Y2O3 coating includes: S1. Pre-treating the substrate; S2, heat treating the pre-treated substrate; S3, spraying the pretreated spray powder onto the surface of the substrate treated in S2 using APS; S4, spraying the suspension plasma spraying slurry onto the coating surface obtained in S3 by using SPS.

2. The suspension plasma spraying slurry according to claim 1, characterized in that: The defoamer comprises one or two of BYK-016 and BYK-012, and the mass fraction in the slurry is 0.05wt%-2.00wt%.

3. A method for preparing a suspension plasma spraying slurry according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) adding yttrium oxide powder to water and polyethylene glycol and milling the mixture in a ball mill; (2) heat treating the obtained slurry; (3) taking out the obtained slurry, adding other components in the formula except yttrium oxide powder, and dispersing by ultrasonication; (4) the obtained slurry is further subjected to secondary ball milling to obtain a suspension plasma spraying slurry; the mass ratio of yttrium oxide powder, water and polyethylene glycol in step (1) is 1:(1-2):(0.1-0.3); the heat treatment in step (2) is first heated to 60-80°C, maintained for 1-2h, then heated to 150-170°C, maintained for 3-5h, and naturally cooled to room temperature.

4. The method for preparing a suspension plasma spraying slurry according to claim 3, characterized in that: In the ball milling of step (1), the ball mill speed is 500-700 rpm and the ball milling time is 4-8 h.

5. The method for preparing a suspension plasma spraying slurry according to claim 3, characterized in that: The ultrasonic dispersion in step (3) is carried out for 10-30 minutes.

6. The method for preparing a suspension plasma spraying slurry according to claim 3, characterized in that: In the secondary ball milling of step (4), the ball mill speed is 200-300 rpm and the ball milling time is 2-3 h.

7. Use of the suspension plasma spraying slurry according to any one of claims 1 to 2 in preparing a low-roughness and etch-resistant Y2O3 coating.

Images