CN112275593B - Method for improving coating microstructure - Google Patents
Method for improving coating microstructure Download PDFInfo
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- CN112275593B CN112275593B CN202011106777.8A CN202011106777A CN112275593B CN 112275593 B CN112275593 B CN 112275593B CN 202011106777 A CN202011106777 A CN 202011106777A CN 112275593 B CN112275593 B CN 112275593B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/36—Successively applying liquids or other fluent materials, e.g. without intermediate treatment
- B05D1/38—Successively applying liquids or other fluent materials, e.g. without intermediate treatment with intermediate treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/12—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by mechanical means
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Coating By Spraying Or Casting (AREA)
Abstract
A method for improving the microstructure of coating layer includes such steps as heating the back of substrate to a certain temp (600-700 deg.C for the back of ceramic powder substrate and 350-450 deg.C for the back of metal powder substrate). During the spraying process, the back surface of the base material is kept heated, and meanwhile, the surface of the deposited coating is strengthened (shot blasting can be adopted for spraying ceramic powder, and laser shock strengthening can be adopted for spraying metal powder). And repeating the steps until the coating reaches a certain thickness, and stopping spraying. The microstructure of the coating is improved by heating the back surface of the base material to a constant temperature and performing impact reinforcement on the surface of the deposited coating in the spraying process. Compared with the coating microstructure prepared by the traditional method, the improved coating microstructure is compact, the porosity is reduced, the layered structure is partially disappeared, and the coating performance is greatly improved.
Description
Technical Field
The invention belongs to the technical field of coating preparation, and particularly relates to a method for improving a coating microstructure.
Background
In recent years, with the optimization of power structures, the development of operation technologies such as deep peak regulation, quality improvement and efficiency improvement, the construction of advanced power generation technologies and large power stations, power equipment faces new and worse working conditions. The equipment such as turbine and pump of thermal power generation and nuclear power, head turbine flow passage component, power station fluid pipeline receive the coupling action of many bad operating modes such as water erosion, cavitation erosion, wearing and tearing and damage speed and degree are increasingly serious in the in-service process. The service life of the part on the coating is higher and higher, and the traditional thermal spraying coating applied to conventional thermal power and hydroelectric equipment for many years is difficult to meet the requirement that the power development cannot be met.
The traditional thermal spraying coating is essentially a layered structure deposition body formed by stacking melted metal or ceramic flat particles, a large amount of unbonded interfaces exist among layers (the interface of the conventional plasma spraying ceramic is unbonded by 70 percent), meanwhile, a large amount of unbonded interfaces exist in the preparation process of the metal coating, the unbonded interfaces are mutually communicated to form pores which are communicated with a base material in the coating, and a corrosive medium in a service environment easily reaches the base material along the through pores and cannot provide effective physical shielding for the base material; under the mechanical action of water erosion, cavitation erosion, abrasion and the like, the coating is peeled off one by taking single flat particles as units, so that the coating is quickly thinned. On the other hand, because the thermal spray coating and the base material are mechanically combined, the bonding strength is relatively low and is usually not higher than 70MPa, and the coating may be peeled off locally or wholly by the high-stress mechanical action of repeated vibration, water erosion, cavitation and the like of the component, so that the coating fails rapidly, and the intrinsic excellent characteristics of the coating material are difficult to exert. The main strategy for improving the service performance and service life of the thermal spraying coating and further meeting the development requirements of the power industry is to improve the bonding proportion among flat particles in the thermal spraying coating and the bonding strength between the coating and a base material.
Disclosure of Invention
In order to solve the above problems, the present invention provides a method for improving the microstructure of a coating, which can effectively improve the interlayer bonding of flat particles in the coating, thereby improving the coating performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method of modifying the microstructure of a coating comprising the steps of:
step 1: before the coating is prepared, degreasing the surface of the base material, and then sandblasting the surface to the required roughness;
step 2: after the sand blasting is finished, the back surface of the base material is heated before spraying, and then spraying is started; in the spraying process, the back surface of the base material is kept heated all the time;
and 3, step 3: strengthening the surface of the deposited coating in the spraying process;
and 4, step 4: repeating the step 2 and the step 3 until the coating reaches the preset thickness, and stopping spraying;
and 5: and after the spraying is stopped, the heating of the back surface of the base material is slowly stopped, and the temperature is kept to be slowly reduced in the stopping process.
The heating mode of the back surface of the base material can be selected from oxyacetylene flame heating, electromagnetic induction heating and the like;
the back heating temperature of the base material is determined according to the type of the powder to be sprayed, the back heating temperature of the ceramic powder base material is 600-700 ℃, and the back heating temperature of the metal powder base material is 350-450 ℃.
The strengthening treatment is determined according to the type of the powder to be sprayed, the ceramic powder can be sprayed by adopting a shot blasting process for strengthening, and the metal powder can be sprayed by adopting laser shock strengthening.
The shot blasting process uses ceramic shots with a chemical composition of approximately 67% ZrO 2 31% of SiO 2 And 2% of Al 2 O 3 The main impurities are prepared by melting, atomizing, drying, selecting round and screening, and the hardness is equal to HRC 57-63; the working pressure of the ceramic pill is 0.4-0.6MPa.
The laser power density of the laser shock peening is 0.4GW/cm 2 ～1.2GW/cm 2 The pulse frequency is adjustable between 0Hz and 10 Hz.
The invention has the following advantages:
1) The invention achieves the purpose of improving the microstructure of the coating by heating the back of the base material to a constant temperature and carrying out impact reinforcement on the surface of the deposited coating in the spraying process, and has simple method and strong operability.
2) Compared with the coating microstructure prepared by the traditional method, the improved coating microstructure is compact, the porosity is reduced, the layered structure is partially disappeared, and the coating performance is greatly improved.
Drawings
Fig. 1 is a schematic view of a typical thermal spray coating microstructure.
FIG. 2 is a schematic view of the microstructure of a thermal spray coating prepared by the method of the present invention.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples.
The invention relates to a method for improving the microstructure of a coating, which comprises the following steps:
step 1: before the coating is prepared, degreasing the surface of the base material, and then sandblasting the surface to the required roughness;
step 2: after the sand blasting is finished, heating the back surface of the base material to a certain temperature before spraying, and then starting spraying; in the spraying process, the back surface of the base material is kept heated all the time;
and 3, step 3: synchronously carrying out strengthening treatment on the surface of the deposited coating in the spraying process;
and 4, step 4: repeating the step 2 and the step 3 until the coating reaches a certain thickness, and stopping spraying;
and 5: and after the spraying is stopped, the heating of the back surface of the base material is slowly stopped, and the temperature is kept to be slowly reduced in the stopping process.
The improved coating microstructure is shown in fig. 2, in contrast to a typical thermal spray coating microstructure (shown in fig. 1), where it can be seen that: after the back surface of the substrate is heated and the surface of the deposited coating is subjected to strengthening treatment, pores in the coating are reduced, a layered structure in the coating is reduced, the density of the coating is obviously improved, and the microstructure of the coating is obviously improved.
Example 1:
the atomized spherical Inconel powder is used as spraying powder (AMPERIT 380, HC)Starck GmbH), particle size 15-45 μm. TP347H heat-resistant steel (1 Cr19Ni11 Nb) was used as a base material, and 16-mesh white corundum sand was subjected to sand blasting under a compressed air pressure of 0.8MPa before spraying. By using M3 TM type-HVAF spray system (Uniquecoat, USA) coatings were prepared under the parameters as shown in table 1. Before spraying, the matrix is preheated to 350 ℃ and then the coating is sprayed, and in the spraying process, the matrix is always kept in a 350 ℃ heating state. After the surface of the base material is sprayed for one time, carrying out laser shock strengthening on the surface of the deposited coating, wherein the laser shock strengthening parameters are as follows: the laser power density is 0.6GW/cm 2 The pulse frequency was 5Hz. And after laser shock, continuing the next spraying and laser shock strengthening treatment, wherein the parameters of each spraying and laser strengthening treatment are the same as those of the first spraying and laser shock strengthening treatment. The above steps were repeated until the coating thickness became 200 μm and was stopped. And carrying out metallographic phase sample preparation on the prepared coating and carrying out microstructure observation under a scanning electron microscope. The results show that the prepared coating has fewer pores, the layered structure in the coating is partially disappeared, and the coating is compact.
TABLE 1 spray parameters for Inconel 625 coatings
Example 2:
TP347H heat-resistant steel (1 Cr19Ni11 Nb) was used as a base material, and 16-mesh white corundum sand was subjected to sand blasting under a compressed air pressure of 0.8MPa before spraying. The melting crushed 8YSZ ceramic powder is selected, and the ceramic coating is prepared by APS spraying technology under the spraying parameter conditions shown in the table 2. Before spraying, the substrate is preheated to 700 ℃ and then starts to be sprayed with the coating, and the substrate is always kept in a 700 ℃ heating state in the spraying process. After the surface of the substrate is sprayed in one pass, the surface of the deposited coating is shot peened using ceramic shot (ZrO with a chemical composition of approximately 67%) 2 31% of SiO 2 And 2% of Al 2 O 3 The main impurities are melted, atomized, dried, selected and screened, and the working pressure of the ceramic pill is 0.5MPa. After shot peening strengthening, the next spraying and shot peening strengthening are continuedThe parameters of each spraying and shot peening treatment are the same as those of the first pass. The above steps were repeated until the coating thickness was 150 μm and then stopped. And carrying out metallographic phase sample preparation on the prepared coating and carrying out microstructure observation under a scanning electron microscope. The results show that the prepared coating has fewer pores, the layered structure in the coating is partially disappeared, and the coating is compact.
TABLE 2 APS spray 8YSZ coating parameters
Claims (4)
1. A method of modifying the microstructure of a coating, comprising: the method comprises the following steps:
step 1: before the coating is prepared, the surface of the base material is subjected to oil stain removal and then is subjected to sand blasting to the required roughness;
step 2: after the sand blasting is finished, heating the back surface of the base material before spraying, and then starting spraying; in the spraying process, the back surface of the base material is kept heated all the time;
and 3, step 3: strengthening the surface of the deposited coating in the spraying process;
and 4, step 4: repeating the step 2 and the step 3 until the coating reaches the preset thickness, and stopping spraying;
and 5: after the spraying is stopped, the heating of the back surface of the base material is slowly stopped, and the temperature is kept to be slowly reduced in the stopping process;
the back heating temperature of the base material is determined according to the type of the powder to be sprayed, the back heating temperature of the ceramic powder spraying base material is 600-700 ℃, and the back heating temperature of the metal powder spraying base material is 350-450 ℃;
the strengthening treatment is determined according to the type of the powder to be sprayed, the ceramic powder is sprayed by adopting a shot blasting process to strengthen, and the metal powder is sprayed by adopting laser shock strengthening.
2. A method of modifying the microstructure of a coating according to claim 1, wherein: the back of the substrate is heated by oxyacetylene flame heating or electromagnetic induction heating.
3. A method of modifying the microstructure of a coating according to claim 1, wherein: the shot blasting process adopts ceramic shots, and the chemical components of the ceramic shots are 67 percent of ZrO 2 31% of SiO 2 And 2% of Al 2 O 3 The impurities are melted, atomized, dried, selected and sieved to prepare the slag with the hardness equal to HRC 57-63; the working pressure of the ceramic pill is 0.4-0.6MPa.
4. A method of modifying the microstructure of a coating according to claim 1, wherein: the laser power density of the laser shock peening is 0.4GW/cm 2 ～1.2GW/cm 2 The pulse frequency is adjusted between 0 and 10 Hz.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101760719A (en) * | 2010-02-05 | 2010-06-30 | 江苏大学 | Method and device of laser impact and thermal spraying composite coating preparation |
| CN106065457A (en) * | 2016-07-29 | 2016-11-02 | 西安交通大学 | Deposited particles combines sufficient plasma spraying ceramic of compact coating and preparation method thereof |
| CN107164731A (en) * | 2017-05-26 | 2017-09-15 | 广东省新材料研究所 | A kind of preparation method of Mg alloy surface aluminium composite armor |
| CN108842124A (en) * | 2018-06-04 | 2018-11-20 | 重庆市科学技术研究院 | A kind of method of laser melting coating reparation and reinforcing mold |
| CN109468572A (en) * | 2018-12-06 | 2019-03-15 | 苏州热工研究院有限公司 | The compound method for increasing material remanufacturing system prepares coating of thermal spraying/laser |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100136296A1 (en) * | 2006-11-30 | 2010-06-03 | United Technologies Corporation | Densification of coating using laser peening |
| WO2015061164A1 (en) * | 2013-10-24 | 2015-04-30 | United Technologies Corporation | Method for enhancing bond strength through in-situ peening |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101760719A (en) * | 2010-02-05 | 2010-06-30 | 江苏大学 | Method and device of laser impact and thermal spraying composite coating preparation |
| CN106065457A (en) * | 2016-07-29 | 2016-11-02 | 西安交通大学 | Deposited particles combines sufficient plasma spraying ceramic of compact coating and preparation method thereof |
| CN107164731A (en) * | 2017-05-26 | 2017-09-15 | 广东省新材料研究所 | A kind of preparation method of Mg alloy surface aluminium composite armor |
| CN108842124A (en) * | 2018-06-04 | 2018-11-20 | 重庆市科学技术研究院 | A kind of method of laser melting coating reparation and reinforcing mold |
| CN109468572A (en) * | 2018-12-06 | 2019-03-15 | 苏州热工研究院有限公司 | The compound method for increasing material remanufacturing system prepares coating of thermal spraying/laser |
Non-Patent Citations (1)
| Title |
|---|
| 微粒轰击Fe基非晶电弧喷涂层性能强化;商俊超等;《中国表面工程》;20171031(第05期);第127页第1.2.1节 * |
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