A method for producing a coating with reduced coating defects and reduced porosity

Abstract

The present invention relates to the technical field of metal coating materials, and in particular to a coating preparation method for reducing coating defects and reducing porosity. Yttrium oxide powder and YAG powder are used together as coating materials, which solves the problem that when spraying YAG powder alone on a substrate, a primer is required for bonding, and the formed YAG coating has many vertical fine lines, and occasionally has lines in other directions, and the yttrium oxide coating formed by spraying yttrium oxide powder alone has many horizontal fine lines, and occasionally has lines in other directions, thereby reducing the porosity of the coating; the yttrium oxide powder is prepared by a precipitation method, and by adding a dispersant, the obtained yttrium oxide powder has a small particle size, a narrow particle size distribution, a large loose density, and good fluidity. After mixing with YAG powder, it has a good conveying state, avoiding the phenomenon of insufficient melting of yttrium oxide powder and overburning of YAG powder, thereby reducing coating defects.

Description

Technical Field

[0001] The invention relates to the technical field of metal coating materials, and in particular to a coating manufacturing method capable of reducing coating defects and reducing porosity. Background Art

[0002] In semiconductor devices, as the minimum feature size decreases, controlling contamination particles is critical in chip manufacturing. However, the introduction of high-density plasma and plasma cleaning in wafer processing promotes the generation of contamination particles. Therefore, plasma-resistant ceramics such as yttrium oxide (Y2O3) and YAG (yttrium aluminum garnet) are used as chamber materials to reduce the generation of contamination particles. Plasma etching resistance is one of the most critical factors in selecting chamber coating materials, and the pores and defects of the coating are key factors affecting its etching resistance.

[0003] There are many horizontal and non-directional fine lines in the traditional single yttrium oxide spraying, vertical fine lines are common in the YAG coating, and other materials need to be used as a primer when YAG is sprayed on the ceramic substrate to prevent it from falling off. Chinese patent application CN101589455A extends the life of yttrium oxide as a plasma chamber material and provides a method for manufacturing a three-layer component of a plasma processing chamber. The three-layer component includes an outer yttrium oxide layer, an intermediate YAG layer, and a second outer aluminum oxide layer. The yttrium oxide layer and the YAG layer are formed separately through a two-step process. Not only does it have many process steps, but the formed layer structure has poor uniformity and high porosity, resulting in a problem of weak etching resistance due to many defects. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides a coating manufacturing method for reducing coating defects and reducing porosity, so as to solve the coating defect problem caused by high porosity of semiconductor cavity coating materials in the prior art.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for producing a coating that reduces coating defects and porosity comprises the following steps:

[0007] Step 1, add 2-acrylamido-2-methylpropanesulfonic acid into deionized water, stir and dissolve, add alkali solution to adjust the pH value to neutral, continue stirring, add polyvinyl pyrrolidone, heat to the set temperature, stir, add potassium persulfate, react, and after the reaction is completed, rotary evaporate and dry to obtain anionic polyvinyl pyrrolidone;

[0008] Step 2, adding anionic polyvinyl pyrrolidone to ethanol, adding alkali solution to adjust the pH value to 7.5-8.5, adding iodomethane, reacting, and after the reaction is completed, rotary evaporation and purification to obtain a zwitterionic dispersant;

[0009] Step 3, dissolving sodium carbonate in deionized water to obtain a precipitant solution;

[0010] Dissolving yttrium chloride and a zwitterionic dispersant in deionized water to obtain a yttrium chloride solution;

[0011] The precipitant solution is added dropwise to the yttrium chloride solution, after the addition is completed, the solution is allowed to stand for aging, filtered, washed, and calcined to obtain yttrium oxide powder;

[0012] Step 4: Mix the yttrium oxide powder and the YAG powder to obtain a mixed powder, and spray the mixed powder onto the surface of the substrate using a plasma spraying process to form a coating that reduces coating defects and reduces porosity.

[0013] Preferably, in step 1, the mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is (6.8-7.6):(60-80):(36-48):(0.04-0.06), and the set temperature is 45-55°C.

[0014] Preferably, in the step 1, the reaction is carried out in a nitrogen atmosphere at a temperature of 75-85° C. for 2.5-3.5 h.

[0015] Preferably, in the step 2, the mass ratio of anionic polyvinyl pyrrolidone, ethanol and methyl iodide is 10:(100-150):(34.2-35.5), and the reaction conditions are reflux reaction at a stirring speed of 600-800 r / min and a temperature of 55-65° C. for 66-78 h.

[0016] Preferably, in the step three, the molar ratio of sodium carbonate to yttrium chloride is 1.2-1.5, the amount of the zwitterionic dispersant is 0.005%-0.01% of the mass of yttrium chloride, the concentration of sodium carbonate in the precipitant solution is 100 g / L, and the concentration of yttrium chloride in the yttrium chloride solution is 100 g / L.

[0017] Preferably, in the step three, the dropping conditions are dropping at a stirring speed of 60-80 r / min, the dropping time is 1-2 h, the standing aging time is 8-12 h, and the calcination temperature is 900-1000°C.

[0018] Preferably, in step 4, the mass ratio of yttrium oxide powder to YAG powder is (2-1):(1-2), and the mixing includes first dry mixing at a stirring speed of 50-100 r / min for 3-6 hours, then adding the dispersion, ultrasonicating at a frequency of 20-60 kHz for 10-20 minutes, and finally wet mixing at a stirring speed of 300-500 r / min for 5-7 hours, filtering, and drying in a vacuum drying oven at 40-50°C for 24-48 hours.

[0019] Furthermore, the dispersion liquid includes any one of deionized water and ethanol, and the amount of the dispersion liquid used is 4-6 times the sum of the mass of the yttrium oxide powder and the YAG powder.

[0020] Preferably, in step 4, the parameters of the plasma spraying process include: argon flow rate of 30-50 L / min, hydrogen flow rate of 5-10 L / min, spraying distance of 100-200 mm, powder feeding amount of 15-30 g / min, current of 500-700 A, and coating thickness of 100-400 μm.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] In the present invention, yttrium oxide powder and YAG powder are used together as coating materials, which solves the problem of low bonding strength when yttrium oxide powder or YAG powder is sprayed alone, the problem that the YAG coating formed by spraying YAG powder alone has many vertical fine lines and occasionally has lines in other directions, and the problem that the yttrium oxide coating formed by spraying yttrium oxide powder alone has many horizontal fine lines and occasionally has lines in other directions, thereby reducing the porosity of the coating;

[0023] The invention uses a precipitation method to prepare yttrium oxide powder. In the preparation process, a dispersant is added to reduce the agglomeration between yttrium oxide precursor particles. Polyvinyl pyrrolidone is used as a high molecular polymer dispersant. The steric hindrance of the long carbon chain of the polymer molecule is used to block the approach of yttrium oxide precursor particles. Under the action of an initiator, 2-acrylamide-2-methylpropanesulfonic acid molecules are grafted onto the polyvinyl pyrrolidone molecular chain, and an anionic group sulfonic acid group is introduced, so that electrostatic repulsion is generated between yttrium oxide precursor particles to prevent particle agglomeration. The tertiary amine group and iodomethyl The alkyl is reacted to generate polyvinyl pyrrolidone quaternary ammonium salt, and the cationic group is introduced, which can generate electrostatic effect with the surface of the yttrium oxide precursor particles, so that the adsorption effect of the zwitterionic dispersant and the yttrium oxide precursor particles is enhanced, and the dispersion effect is further enhanced. The prepared yttrium oxide powder has a small particle size, a narrow particle size distribution, a large loose density, and good fluidity; thereby, the yttrium oxide powder and the YAG powder are mixed, and have a good conveying state, avoiding the phenomenon of insufficient melting of the yttrium oxide powder and overburning of the YAG powder, thereby reducing the porosity and reducing the coating defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a process flow chart for preparing a coating that reduces coating defects and reduces porosity;

[0025] Figure 2 It is a bar chart showing the particle size measurement results of the yttrium oxide powders prepared in Examples 1-6 and Comparative Examples 1-2 of the present invention;

[0026] Figure 3 It is a bar graph showing the particle size distribution index measurement results of the yttrium oxide powders prepared in Examples 1-6 and Comparative Examples 1-2 of the present invention;

[0027] Figure 4 The bar graph is a measurement result of the bulk density of the yttrium oxide powders prepared in Examples 1-6 and Comparative Examples 1-2 of the present invention;

[0028] Figure 5 A bar graph showing the porosity measurement results of the coatings prepared in Examples 1-6 and Comparative Examples 1-2 of the present invention;

[0029] Figure 6 is a backscattered electron image of the coating prepared in Example 1 of the present invention;

[0030] Figure 7 is a backscattered electron image of the coating prepared in Example 2 of the present invention;

[0031] Figure 8 is a backscattered electron image of the coating prepared in Example 3 of the present invention;

[0032] Fig. 9 is a backscattered electron image of the coating prepared in Example 4 of the present invention;

[0033] Fig.10 is a backscattered electron image of the coating prepared in Example 5 of the present invention;

[0034] Fig.11 is a backscattered electron image of the coating prepared in Example 6 of the present invention;

[0035] Fig.12 is a backscattered electron image of the coating prepared in Comparative Example 1 of the present invention;

[0036] Fig.13 This is a backscattered electron image of the coating prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0037] Example 1

[0038] This embodiment discloses a coating manufacturing method for reducing coating defects and reducing porosity, comprising the following steps:

[0039] Step 1, add 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir and dissolve at room temperature at a stirring speed of 150r / min, add 1mol / L sodium hydroxide aqueous solution to adjust the pH value to neutral, continue stirring at room temperature at a stirring speed of 150r / min, add polyvinyl pyrrolidone, heat to 45°C, stir for 30min at a stirring speed of 150r / min in a nitrogen atmosphere, add potassium persulfate, the mass ratio of 2-acrylamide-2-methylpropane sulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is 6.8:60:36:0.04, react at a temperature of 75°C in a nitrogen atmosphere for 3.5h, after the reaction is completed, remove the deionized water by rotary evaporation at a temperature of 60°C, and then place in a vacuum drying oven at 50°C for 10h to obtain anionic polyvinyl pyrrolidone;

[0040] Step 2, adding anionic polyvinyl pyrrolidone to ethanol, adding 1 mol / L sodium hydroxide aqueous solution to adjust the pH value to 7.5, adding iodomethane, the mass ratio of anionic polyvinyl pyrrolidone, ethanol and iodomethane is 10:100:34.2, stirring at a speed of 600 r / min and reflux at a temperature of 55°C for 78 hours, after the reaction is completed, rotary evaporation is performed at a temperature of 50°C to remove ethanol, and recrystallization is performed 3 times with ethanol and ether, and rotary evaporation is performed at room temperature and then placed in a 50°C vacuum drying oven for 10 hours to obtain a zwitterionic dispersant;

[0041] Step 3, dissolving sodium carbonate in deionized water to obtain a precipitant solution, wherein the concentration of sodium carbonate in the precipitant solution is 100 g / L, dissolving yttrium chloride and a zwitterionic dispersant in deionized water to obtain a yttrium chloride feed solution, wherein the concentration of yttrium chloride in the yttrium chloride feed solution is 100 g / L, the molar ratio of sodium carbonate to yttrium chloride is 1.2, and the amount of the zwitterionic dispersant is 0.005% of the mass of yttrium chloride;

[0042] The precipitant solution was added dropwise to the yttrium chloride solution at a stirring speed of 60 r / min for 1 hour. After the addition was completed, the solution was allowed to stand for 8 hours, and then the precipitate was filtered out, washed with deionized water for 3 times, and calcined at 900° C. for 3 hours to obtain yttrium oxide powder.

[0043] Step 4: dry-mix the yttrium oxide powder and the YAG powder at a mass ratio of 2:1 at a stirring speed of 50 r / min for 6 hours, then add deionized water 4 times the mass of the yttrium oxide powder and the YAG powder, ultrasonicate at a frequency of 20 kHz for 20 minutes, and finally wet-mix at a stirring speed of 300 r / min for 7 hours, filter, and dry in a vacuum drying oven at 40° C. for 48 hours to obtain a mixed powder, and use a plasma spraying process to spray the mixed powder on the surface of the ceramic substrate to form a coating that reduces coating defects and reduces porosity;

[0044] The parameters of the plasma spraying process include: argon flow rate of 30 L / min, hydrogen flow rate of 5 L / min, spraying distance of 100 mm, powder feeding amount of 15 g / min, current of 500 A, and coating thickness of 250 μm.

[0045] Example 2

[0046] This embodiment discloses a coating manufacturing method for reducing coating defects and reducing porosity, comprising the following steps:

[0047] Step 1, add 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir and dissolve at room temperature at a stirring speed of 150r / min, add 1mol / L sodium hydroxide aqueous solution to adjust the pH value to neutral, continue stirring at room temperature at a stirring speed of 150r / min, add polyvinyl pyrrolidone, heat to 55°C, stir for 30min at a stirring speed of 150r / min in a nitrogen atmosphere, add potassium persulfate, the mass ratio of 2-acrylamide-2-methylpropane sulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is 7.5:80:48:0.06, react at a temperature of 85°C in a nitrogen atmosphere for 2.5h, after the reaction is completed, remove the deionized water by rotary evaporation at a temperature of 60°C, and then place in a vacuum drying oven at 50°C for 10h to obtain anionic polyvinyl pyrrolidone;

[0048] Step 2, adding anionic polyvinyl pyrrolidone to ethanol, adding 1 mol / L sodium hydroxide aqueous solution to adjust the pH value to 8.5, adding iodomethane, the mass ratio of anionic polyvinyl pyrrolidone, ethanol and iodomethane is 10:150:35.5, stirring at a speed of 800 r / min and reflux at 65°C for 66 hours, after the reaction is completed, rotary evaporation is performed at 50°C to remove ethanol, recrystallization is performed 3 times with ethanol and ether, rotary evaporation is performed at room temperature, and then placed in a 50°C vacuum drying oven for 10 hours to obtain a zwitterionic dispersant;

[0049] Step 3, dissolving sodium carbonate in deionized water to obtain a precipitant solution, wherein the concentration of sodium carbonate in the precipitant solution is 100 g / L, dissolving yttrium chloride and a zwitterionic dispersant in deionized water to obtain a yttrium chloride feed solution, wherein the concentration of yttrium chloride in the yttrium chloride feed solution is 100 g / L, the molar ratio of sodium carbonate to yttrium chloride is 1.5, and the amount of the zwitterionic dispersant is 0.01% of the mass of yttrium chloride;

[0050] The precipitant solution was added dropwise to the yttrium chloride solution at a stirring speed of 80 r / min for 2 hours. After the addition was completed, the solution was allowed to stand for 12 hours, and then the precipitate was filtered out and washed with deionized water for 3 times. The precipitate was calcined at 1000° C. for 2 hours to obtain yttrium oxide powder.

[0051] Step 4: dry-mix the yttrium oxide powder and the YAG powder at a mass ratio of 1:2 at a stirring speed of 100 r / min for 3 hours, then add deionized water 6 times the mass of the yttrium oxide powder and the YAG powder, ultrasonicate at a frequency of 60 kHz for 10 minutes, and finally wet-mix at a stirring speed of 500 r / min for 5 hours, filter, and dry in a vacuum drying oven at 50° C. for 24 hours to obtain a mixed powder, and use a plasma spraying process to spray the mixed powder on the surface of the ceramic substrate to form a coating that reduces coating defects and reduces porosity;

[0052] The parameters of the plasma spraying process include: argon flow rate of 50 L / min, hydrogen flow rate of 10 L / min, spraying distance of 200 mm, powder feeding amount of 30 g / min, current of 700 A, and coating thickness of 250 μm.

[0053] Example 3

[0054] This embodiment discloses a coating manufacturing method for reducing coating defects and reducing porosity, comprising the following steps:

[0055] Step 1, add 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir and dissolve at room temperature at a stirring speed of 150r / min, add 1mol / L sodium hydroxide aqueous solution to adjust the pH value to neutral, continue stirring at room temperature at a stirring speed of 150r / min, add polyvinyl pyrrolidone, heat to 50°C, stir for 30min at a stirring speed of 150r / min in a nitrogen atmosphere, add potassium persulfate, the mass ratio of 2-acrylamide-2-methylpropane sulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is 7:64:38:0.05, react at 80°C in a nitrogen atmosphere for 3h, after the reaction is completed, remove the deionized water by rotary evaporation at 60°C, and then place in a 50°C vacuum drying oven for 10h to obtain anionic polyvinyl pyrrolidone;

[0056] Step 2, adding anionic polyvinyl pyrrolidone to ethanol, adding 1 mol / L sodium hydroxide aqueous solution to adjust the pH value to 8, adding iodomethane, the mass ratio of anionic polyvinyl pyrrolidone, ethanol and iodomethane is 10:110:34.5, stirring at a speed of 700 r / min and reflux at 60°C for 72 hours, after the reaction is completed, rotary evaporation is performed at 50°C to remove ethanol, recrystallization is performed with ethanol and ether for 3 times, rotary evaporation is performed at room temperature, and then placed in a 50°C vacuum drying oven for 10 hours to obtain a zwitterionic dispersant;

[0057] Step 3, dissolving sodium carbonate in deionized water to obtain a precipitant solution, wherein the concentration of sodium carbonate in the precipitant solution is 100 g / L, dissolving yttrium chloride and a zwitterionic dispersant in deionized water to obtain a yttrium chloride feed solution, wherein the concentration of yttrium chloride in the yttrium chloride feed solution is 100 g / L, the molar ratio of sodium carbonate to yttrium chloride is 1.3, and the amount of the zwitterionic dispersant is 0.006% of the mass of yttrium chloride;

[0058] The precipitant solution was added dropwise to the yttrium chloride solution at a stirring speed of 70 r / min for 1.5 h. After the addition was completed, the precipitate was allowed to stand for 10 h, filtered, washed with deionized water for 3 times, and calcined at 950 ° C for 2.5 h to obtain yttrium oxide powder.

[0059] Step 4: dry-mix the yttrium oxide powder and the YAG powder in a mass ratio of 1:1 at a stirring speed of 80 r / min for 4.5 h, then add deionized water 5 times the mass of the yttrium oxide powder and the YAG powder, ultrasonicate at a frequency of 40 kHz for 15 min, and finally wet-mix at a stirring speed of 400 r / min for 6 h, filter, and dry in a vacuum drying oven at 45° C. for 36 h to obtain a mixed powder, and use a plasma spraying process to spray the mixed powder on the surface of the ceramic substrate to form a coating that reduces coating defects and reduces porosity;

[0060] The parameters of the plasma spraying process include: argon flow rate of 40 L / min, hydrogen flow rate of 8 L / min, spraying distance of 150 mm, powder feeding amount of 25 g / min, current of 600 A, and coating thickness of 250 μm.

[0061] Example 4

[0062] This embodiment discloses a coating manufacturing method for reducing coating defects and reducing porosity, comprising the following steps:

[0063] Step 1, add 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir and dissolve at room temperature at a stirring speed of 150r / min, add 1mol / L sodium hydroxide aqueous solution to adjust the pH value to neutral, continue stirring at room temperature at a stirring speed of 150r / min, add polyvinyl pyrrolidone, heat to 50°C, stir for 30min at a stirring speed of 150r / min in a nitrogen atmosphere, add potassium persulfate, the mass ratio of 2-acrylamide-2-methylpropane sulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is 7.2:68:40:0.05, react at 80°C in a nitrogen atmosphere for 3h, after the reaction is completed, remove the deionized water by rotary evaporation at 60°C, and then place in a 50°C vacuum drying oven for 10h to obtain anionic polyvinyl pyrrolidone;

[0064] Step 2, adding anionic polyvinyl pyrrolidone to ethanol, adding 1 mol / L sodium hydroxide aqueous solution to adjust the pH value to 8, adding iodomethane, the mass ratio of anionic polyvinyl pyrrolidone, ethanol and iodomethane is 10:120:34.8, stirring at a speed of 700 r / min and reflux at 60°C for 72 hours, after the reaction, rotary evaporation at 50°C to remove ethanol, recrystallization with ethanol and ether 3 times, rotary evaporation at room temperature, and then drying in a 50°C vacuum drying oven for 10 hours to obtain a zwitterionic dispersant;

[0065] Step 3, dissolving sodium carbonate in deionized water to obtain a precipitant solution, wherein the concentration of sodium carbonate in the precipitant solution is 100 g / L, dissolving yttrium chloride and a zwitterionic dispersant in deionized water to obtain a yttrium chloride feed solution, wherein the concentration of yttrium chloride in the yttrium chloride feed solution is 100 g / L, the molar ratio of sodium carbonate to yttrium chloride is 1.35, and the amount of the zwitterionic dispersant is 0.007% of the mass of yttrium chloride;

[0066] The precipitant solution was added dropwise to the yttrium chloride solution at a stirring speed of 70 r / min for 1.5 h. After the addition was completed, the precipitate was allowed to stand for 10 h, filtered, washed with deionized water for 3 times, and calcined at 950 ° C for 2.5 h to obtain yttrium oxide powder.

[0067] Step 4: dry-mix the yttrium oxide powder and the YAG powder in a mass ratio of 1:1 at a stirring speed of 80 r / min for 4.5 h, then add deionized water 5 times the mass of the yttrium oxide powder and the YAG powder, ultrasonicate at a frequency of 40 kHz for 15 min, and finally wet-mix at a stirring speed of 400 r / min for 6 h, filter, and dry in a vacuum drying oven at 45° C. for 36 h to obtain a mixed powder, and use a plasma spraying process to spray the mixed powder on the surface of the ceramic substrate to form a coating that reduces coating defects and reduces porosity;

[0068] The parameters of the plasma spraying process include: argon flow rate of 40 L / min, hydrogen flow rate of 8 L / min, spraying distance of 150 mm, powder feeding amount of 25 g / min, current of 600 A, and coating thickness of 250 μm.

[0069] Example 5

[0070] This embodiment discloses a coating manufacturing method for reducing coating defects and reducing porosity, comprising the following steps:

[0071] Step 1, add 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir and dissolve at room temperature at a stirring speed of 150r / min, add 1mol / L sodium hydroxide aqueous solution to adjust the pH value to neutral, continue stirring at room temperature at a stirring speed of 150r / min, add polyvinyl pyrrolidone, heat to 50°C, stir for 30min at a stirring speed of 150r / min in a nitrogen atmosphere, add potassium persulfate, the mass ratio of 2-acrylamide-2-methylpropane sulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is 7.4:72:42:0.05, react at 80°C in a nitrogen atmosphere for 3h, after the reaction is completed, remove the deionized water by rotary evaporation at 60°C, and then place in a 50°C vacuum drying oven for 10h to obtain anionic polyvinyl pyrrolidone;

[0072] Step 2, adding anionic polyvinyl pyrrolidone to ethanol, adding 1 mol / L sodium hydroxide aqueous solution to adjust the pH value to 8, adding iodomethane, the mass ratio of anionic polyvinyl pyrrolidone, ethanol and iodomethane is 10:130:35, stirring at a speed of 700 r / min and reflux at 60°C for 72 hours, after the reaction, rotary evaporation at 50°C to remove ethanol, recrystallization with ethanol and ether 3 times, rotary evaporation at room temperature, and then drying in a 50°C vacuum drying oven for 10 hours to obtain a zwitterionic dispersant;

[0073] Step 3, dissolving sodium carbonate in deionized water to obtain a precipitant solution, wherein the concentration of sodium carbonate in the precipitant solution is 100 g / L, dissolving yttrium chloride and a zwitterionic dispersant in deionized water to obtain a yttrium chloride feed solution, wherein the concentration of yttrium chloride in the yttrium chloride feed solution is 100 g / L, the molar ratio of sodium carbonate to yttrium chloride is 1.35, and the amount of the zwitterionic dispersant is 0.008% of the mass of yttrium chloride;

[0074] The precipitant solution was added dropwise to the yttrium chloride solution at a stirring speed of 70 r / min for 1.5 h. After the addition was completed, the precipitate was allowed to stand for 10 h, filtered, washed with deionized water for 3 times, and calcined at 950 ° C for 2.5 h to obtain yttrium oxide powder.

[0075] Step 4: dry-mix the yttrium oxide powder and the YAG powder in a mass ratio of 1:1 at a stirring speed of 80 r / min for 4.5 h, then add deionized water 5 times the mass of the yttrium oxide powder and the YAG powder, ultrasonicate at a frequency of 40 kHz for 15 min, and finally wet-mix at a stirring speed of 400 r / min for 6 h, filter, and dry in a vacuum drying oven at 45° C. for 36 h to obtain a mixed powder, and use a plasma spraying process to spray the mixed powder on the surface of the ceramic substrate to form a coating that reduces coating defects and reduces porosity;

[0076] The parameters of the plasma spraying process include: argon flow rate of 40 L / min, hydrogen flow rate of 8 L / min, spraying distance of 150 mm, powder feeding amount of 25 g / min, current of 600 A, and coating thickness of 250 μm.

[0077] Example 6

[0078] This embodiment discloses a coating manufacturing method for reducing coating defects and reducing porosity, comprising the following steps:

[0079] Step 1, add 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir and dissolve at room temperature at a stirring speed of 150r / min, add 1mol / L sodium hydroxide aqueous solution to adjust the pH value to neutral, continue stirring at room temperature at a stirring speed of 150r / min, add polyvinyl pyrrolidone, heat to 50°C, stir for 30min at a stirring speed of 150r / min in a nitrogen atmosphere, add potassium persulfate, the mass ratio of 2-acrylamide-2-methylpropane sulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is 7.5:76:45:0.05, react at 80°C in a nitrogen atmosphere for 3h, after the reaction is completed, remove the deionized water by rotary evaporation at 60°C, and then place in a 50°C vacuum drying oven for 10h to obtain anionic polyvinyl pyrrolidone;

[0080] Step 2, adding anionic polyvinyl pyrrolidone to ethanol, adding 1 mol / L sodium hydroxide aqueous solution to adjust the pH value to 8, adding iodomethane, the mass ratio of anionic polyvinyl pyrrolidone, ethanol and iodomethane is 10:140:35.3, stirring at a speed of 700 r / min and reflux at 60°C for 72 hours, after the reaction, rotary evaporation at 50°C to remove ethanol, recrystallization with ethanol and ether 3 times, rotary evaporation at room temperature, and then drying in a 50°C vacuum drying oven for 10 hours to obtain a zwitterionic dispersant;

[0081] Step 3, dissolving sodium carbonate in deionized water to obtain a precipitant solution, wherein the concentration of sodium carbonate in the precipitant solution is 100 g / L, dissolving yttrium chloride and a zwitterionic dispersant in deionized water to obtain a yttrium chloride feed solution, wherein the concentration of yttrium chloride in the yttrium chloride feed solution is 100 g / L, the molar ratio of sodium carbonate to yttrium chloride is 1.4, and the amount of the zwitterionic dispersant is 0.007% of the mass of yttrium chloride;

[0082] The precipitant solution was added dropwise to the yttrium chloride solution at a stirring speed of 70 r / min for 1.5 h. After the addition was completed, the precipitate was allowed to stand for 10 h, filtered, washed with deionized water for 3 times, and calcined at 950 ° C for 2.5 h to obtain yttrium oxide powder.

[0083] Step 4: dry-mix the yttrium oxide powder and the YAG powder in a mass ratio of 1:1 at a stirring speed of 80 r / min for 4.5 h, then add deionized water 5 times the mass of the yttrium oxide powder and the YAG powder, ultrasonicate at a frequency of 40 kHz for 15 min, and finally wet-mix at a stirring speed of 400 r / min for 6 h, filter, and dry in a vacuum drying oven at 45° C. for 36 h to obtain a mixed powder, and use a plasma spraying process to spray the mixed powder on the surface of the ceramic substrate to form a coating that reduces coating defects and reduces porosity;

[0084] The parameters of the plasma spraying process include: argon flow rate of 40 L / min, hydrogen flow rate of 8 L / min, spraying distance of 150 mm, powder feeding amount of 25 g / min, current of 600 A, and coating thickness of 250 μm.

[0085] Comparative Example 1

[0086] This comparative example discloses a coating preparation method for reducing coating defects and reducing porosity, comprising the following steps:

[0087] Step 1, add 2-acrylamide-2-methylpropane sulfonic acid to deionized water, stir and dissolve at room temperature at a stirring speed of 150r / min, add 1mol / L sodium hydroxide aqueous solution to adjust the pH value to neutral, continue stirring at room temperature at a stirring speed of 150r / min, add polyvinyl pyrrolidone, heat to 45°C, stir for 30min at a stirring speed of 150r / min in a nitrogen atmosphere, add potassium persulfate, the mass ratio of 2-acrylamide-2-methylpropane sulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is 6.8:60:36:0.04, react at a temperature of 75°C in a nitrogen atmosphere for 3.5h, after the reaction is completed, remove the deionized water by rotary evaporation at a temperature of 60°C, and then place in a vacuum drying oven at 50°C for 10h to obtain anionic polyvinyl pyrrolidone;

[0088] Step 2, dissolving sodium carbonate in deionized water to obtain a precipitant solution, wherein the concentration of sodium carbonate in the precipitant solution is 100 g / L, dissolving yttrium chloride and anionic polyvinyl pyrrolidone in deionized water to obtain a yttrium chloride feed solution, wherein the concentration of yttrium chloride in the yttrium chloride feed solution is 100 g / L, the molar ratio of sodium carbonate to yttrium chloride is 1.2, and the amount of anionic polyvinyl pyrrolidone is 0.005% of the mass of yttrium chloride;

[0089] The precipitant solution was added dropwise to the yttrium chloride solution at a stirring speed of 60 r / min for 1 hour. After the addition was completed, the solution was allowed to stand for 8 hours, and then the precipitate was filtered out, washed with deionized water for 3 times, and calcined at 900° C. for 3 hours to obtain yttrium oxide powder.

[0090] Step 3, dry-mix the yttrium oxide powder and the YAG powder at a mass ratio of 2:1 at a stirring speed of 50 r / min for 6 hours, then add deionized water 4 times the mass of the yttrium oxide powder and the YAG powder, ultrasonicate at a frequency of 20 kHz for 20 minutes, and finally wet-mix at a stirring speed of 300 r / min for 7 hours, filter, and dry in a vacuum drying oven at 40° C. for 48 hours to obtain a mixed powder, and use a plasma spraying process to spray the mixed powder on the surface of the ceramic substrate to form a coating that reduces coating defects and reduces porosity;

[0091] The parameters of the plasma spraying process include: argon flow rate of 30 L / min, hydrogen flow rate of 5 L / min, spraying distance of 100 mm, powder feeding amount of 15 g / min, current of 500 A, and coating thickness of 250 μm.

[0092] Comparative Example 2

[0093] This comparative example discloses a coating preparation method for reducing coating defects and reducing porosity, comprising the following steps:

[0094] Step 1, dissolving sodium carbonate in deionized water to obtain a precipitant solution, wherein the concentration of sodium carbonate in the precipitant solution is 100 g / L, dissolving yttrium chloride and polyvinyl pyrrolidone in deionized water to obtain a yttrium chloride feed solution, wherein the concentration of yttrium chloride in the yttrium chloride feed solution is 100 g / L, the molar ratio of sodium carbonate to yttrium chloride is 1.2, and the amount of polyvinyl pyrrolidone is 0.005% of the mass of yttrium chloride;

[0095] The precipitant solution was added dropwise to the yttrium chloride solution at a stirring speed of 60 r / min for 1 hour. After the addition was completed, the solution was allowed to stand for 8 hours, and then the precipitate was filtered out, washed with deionized water for 3 times, and calcined at 900° C. for 3 hours to obtain yttrium oxide powder.

[0096] Step 2: dry-mix the yttrium oxide powder and the YAG powder at a mass ratio of 2:1 at a stirring speed of 50 r / min for 6 hours, then add deionized water 4 times the mass of the yttrium oxide powder and the YAG powder, ultrasonicate at a frequency of 20 kHz for 20 minutes, and finally wet-mix at a stirring speed of 300 r / min for 7 hours, filter, and dry in a vacuum drying oven at 40° C. for 48 hours to obtain a mixed powder, and use a plasma spraying process to spray the mixed powder on the surface of the ceramic substrate to form a coating that reduces coating defects and reduces porosity;

[0097] The parameters of the plasma spraying process include: argon flow rate of 30 L / min, hydrogen flow rate of 5 L / min, spraying distance of 100 mm, powder feeding amount of 15 g / min, current of 500 A, and coating thickness of 250 μm.

[0098] In the above embodiments and comparative examples, polyvinyl pyrrolidone was purchased from Tianjin Baima Technology Co., Ltd., model: P816207, average molecular weight: 24000; YAG powder was purchased from Guangzhou Nano Chemical Co., Ltd., particle size range: 20-60 μm, purity ≥99.99%.

[0099] Test example

[0100] (1) The particle size, particle size distribution index and bulk density of the yttrium oxide powders prepared in Examples 1-6 and Comparative Examples 1-2 were measured. The particle size and particle size distribution index of the yttrium oxide powders were measured using a Coulter Ls230 laser particle size analyzer, and the bulk density of the powders was measured using a Hall flow meter (funnel method). The measurement results are shown in Table 1:

[0101] Table 1

[0102]

[0103] As shown in Table 1, the yttrium oxide powder prepared by the present invention has a small particle size, a narrow particle size distribution, and a large bulk density. In the process of preparing yttrium oxide powder by precipitation method, a dispersant is added to reduce the agglomeration between yttrium oxide precursor particles. The dispersant in the present invention is a high molecular polymer dispersant polyvinyl pyrrolidone that is modified and prepared. First, a grafting reaction occurs with 2-acrylamide-2-methylpropane sulfonic acid under the action of an initiator to introduce an anionic group sulfonic acid group, and then reacts with iodomethane to generate a cationic group quaternary ammonium salt. The steric hindrance of the long carbon chain of polyvinyl pyrrolidone can block the approach of yttrium oxide precursor particles, and the anionic group generates electrostatic repulsion between yttrium oxide precursor particles to prevent particle agglomeration. The cationic group can generate an electrostatic effect with the surface of the yttrium oxide precursor particles, so that the adsorption of the zwitterionic dispersant and the yttrium oxide precursor particles is enhanced, and the dispersion effect is further enhanced. Compared with Example 1, in Comparative Example 1, anionic polyvinyl pyrrolidone is used as a dispersant, and no quaternary ammonium salt is further formed, and the dispersion effect is reduced; compared with Comparative Example 1, in Comparative Example 2, only a high molecular polymer dispersant polyvinyl pyrrolidone is used as a dispersant, and the dispersion effect is further reduced.

[0104] (2) The properties of the coatings prepared in Examples 1-6 and Comparative Examples 1-2 were measured. The test results are shown in Table 2:

[0105] Table 2

[0106]

[0107] As can be seen from Table 2, the coating prepared by the present invention has low porosity, high bonding strength with the ceramic matrix, and few coating defects. Compared with spraying YAG powder alone, the combination of yttrium oxide powder and YAG powder has good bonding strength between the coating and the ceramic matrix. When the mass ratio of yttrium oxide powder to YAG powder is 1:1, the bonding strength of the coating is the highest; during the preparation of yttrium oxide powder by precipitation method, a zwitterionic dispersant modified with polyvinyl pyrrolidone is used. The yttrium oxide powder has a small particle size, a narrow particle size distribution, a large bulk density, a dense structure, and good fluidity. When mixed with YAG powder, it can avoid the phenomenon of insufficient melting of yttrium oxide powder and overburning of YAG powder, thereby reducing porosity and coating defects. Compared with Example 1, in Comparative Example 1, when preparing yttrium oxide powder, anionic polyvinyl pyrrolidone is used as a dispersant, and no quaternary ammonium salt is further formed, the dispersion effect is reduced, the particle size distribution index of the prepared yttrium oxide powder becomes larger, the fluidity is weakened, the loose density is reduced, and the porosity of the coating is increased; compared with Comparative Example 1, in Comparative Example 2, only the high molecular polymer dispersant polyvinyl pyrrolidone is used as a dispersant, the dispersion effect is further reduced, the particle size distribution index of the yttrium oxide powder becomes larger, the loose density is further reduced, and the porosity of the coating is further increased.

[0108] 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 method for producing a coating with reduced coating defects and reduced porosity, characterized in that: The steps include: Step 1, add 2-acrylamido-2-methylpropanesulfonic acid into deionized water, stir and dissolve, add alkali solution to adjust the pH value to neutral, continue stirring, add polyvinyl pyrrolidone, heat to the set temperature, stir, add potassium persulfate, react, and after the reaction is completed, rotary evaporate and dry to obtain anionic polyvinyl pyrrolidone; Step 2, adding anionic polyvinyl pyrrolidone to ethanol, adding alkali solution to adjust the pH value to 7.5-8.5, adding iodomethane, reacting, and after the reaction is completed, rotary evaporation and purification to obtain a zwitterionic dispersant; Step 3, dissolving sodium carbonate in deionized water to obtain a precipitant solution; Dissolving yttrium chloride and a zwitterionic dispersant in deionized water to obtain a yttrium chloride solution; The precipitant solution is added dropwise to the yttrium chloride solution, after the addition is completed, the solution is allowed to stand for aging, filtered, washed, and calcined to obtain yttrium oxide powder; Among them, the dosage of zwitterionic dispersant is 0.005%-0.01% of the mass of yttrium chloride; Step 4: Mix the yttrium oxide powder and the YAG powder to obtain a mixed powder, and spray the mixed powder onto the surface of the substrate using a plasma spraying process to form a coating that reduces coating defects and reduces porosity.

2. A coating preparation method for reducing coating defects and reducing porosity according to claim 1, characterized in that: In the step 1, the mass ratio of 2-acrylamido-2-methylpropanesulfonic acid, deionized water, polyvinyl pyrrolidone and potassium persulfate is (6.8-7.6):(60-80):(36-48):(0.04-0.06), and the set temperature is 45-55°C.

3. A coating preparation method for reducing coating defects and reducing porosity according to claim 1, characterized in that: In the step 1, the reaction conditions are in a nitrogen atmosphere at a temperature of 75-85° C. for 2.5-3.5 hours.

4. A coating manufacturing method for reducing coating defects and reducing porosity according to claim 1, characterized in that: In the step 2, the mass ratio of anionic polyvinyl pyrrolidone, ethanol and methyl iodide is 10:(100-150):(34.2-35.5), and the reaction conditions are stirring at a speed of 600-800 r / min and a temperature of 55-65° C. for reflux reaction for 66-78 hours.

5. A coating preparation method for reducing coating defects and reducing porosity according to claim 1, characterized in that: In the step three, the molar ratio of sodium carbonate to yttrium chloride is 1.2-1.5, the concentration of sodium carbonate in the precipitant solution is 100 g / L, and the concentration of yttrium chloride in the yttrium chloride solution is 100 g / L.

6. A coating manufacturing method for reducing coating defects and reducing porosity according to claim 1, characterized in that: In the step three, the dropping conditions are: dropping at a stirring speed of 60-80 r / min, the dropping time is 1-2 h, the standing aging time is 8-12 h, and the calcination temperature is 900-1000° C.

7. A coating manufacturing method for reducing coating defects and reducing porosity according to claim 1, characterized in that: In the step 4, the mass ratio of yttrium oxide powder to YAG powder is (2-1):(1-2).

8. A coating manufacturing method for reducing coating defects and reducing porosity according to claim 1, characterized in that: In the step 4, the mixing includes first dry mixing at a stirring speed of 50-100 r / min for 3-6 hours, then adding the dispersion, ultrasonicating at a frequency of 20-60 kHz for 10-20 minutes, and finally wet mixing at a stirring speed of 300-500 r / min for 5-7 hours, filtering, and drying in a vacuum drying oven at 40-50° C. for 24-48 hours.

9. A method for producing a coating with reduced coating defects and reduced porosity according to claim 8, characterized in that: The dispersion liquid includes any one of deionized water and ethanol, and the amount of the dispersion liquid used is 4-6 times the total mass of the yttrium oxide powder and the YAG powder.

10. A coating manufacturing method for reducing coating defects and reducing porosity according to claim 1, characterized in that: In step 4, the parameters of the plasma spraying process include: argon flow rate of 30-50 L / min, hydrogen flow rate of 5-10 L / min, spraying distance of 100-200 mm, powder feeding amount of 15-30 g / min, current of 500-700 A, and coating thickness of 100-400 μm.

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