CN112275593B - Method for improving coating microstructure - Google Patents

Method for improving coating microstructure Download PDF

Info

Publication number
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
Authority
CN
China
Prior art keywords
coating
spraying
base material
microstructure
heating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202011106777.8A
Other languages
Chinese (zh)
Other versions
CN112275593A (en
Inventor
杨二娟
刘福广
米紫昊
李勇
刘刚
王博
王艳松
韩天鹏
杨兰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xian Thermal Power Research Institute Co Ltd
Original Assignee
Xian Thermal Power Research Institute Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xian Thermal Power Research Institute Co Ltd filed Critical Xian Thermal Power Research Institute Co Ltd
Priority to CN202011106777.8A priority Critical patent/CN112275593B/en
Publication of CN112275593A publication Critical patent/CN112275593A/en
Application granted granted Critical
Publication of CN112275593B publication Critical patent/CN112275593B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • 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
    • 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
    • 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

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

Method for improving coating microstructure
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
Figure BDA0002727167640000051
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
Figure BDA0002727167640000061
。

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.
CN202011106777.8A 2020-10-16 2020-10-16 Method for improving coating microstructure Active CN112275593B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011106777.8A CN112275593B (en) 2020-10-16 2020-10-16 Method for improving coating microstructure

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011106777.8A CN112275593B (en) 2020-10-16 2020-10-16 Method for improving coating microstructure

Publications (2)

Publication Number Publication Date
CN112275593A CN112275593A (en) 2021-01-29
CN112275593B true CN112275593B (en) 2023-02-28

Family

ID=74496357

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011106777.8A Active CN112275593B (en) 2020-10-16 2020-10-16 Method for improving coating microstructure

Country Status (1)

Country Link
CN (1) CN112275593B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113186526B (en) * 2021-04-30 2022-07-19 广东省科学院新材料研究所 Metal coating and preparation method thereof

Citations (5)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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
US9938624B2 (en) * 2013-10-24 2018-04-10 United Technologies Corporation Method for enhancing bond strength through in-situ peening

Patent Citations (5)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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 *

Also Published As

Publication number Publication date
CN112275593A (en) 2021-01-29

Similar Documents

Publication Publication Date Title
US8486496B2 (en) Method of preparing wear-resistant coating layer comprising metal matrix composite and coating layer prepared thereby
CN107723699B (en) Method for repairing heat-resistant alloy
CN109266997B (en) Metal workpiece double-layer coating suitable for high-temperature environment and manufacturing method thereof
CN102154609A (en) Preparation method of high-precision roller wear-resistant coating
CN105132908A (en) Gas turbine blade thermal barrier coating bonding layer and preparation method thereof
CN103009704A (en) Nanometer/columnar-like crystal mixing structure thermal barrier coating and preparation method thereof
WO2022152264A1 (en) Nicrbsi-zrb2 metal ceramic powder for high temperature protection, composite coating and preparation method therefor
EP1932928B1 (en) Densification of coating using laser peening
CN113373400B (en) Preparation method of wear-resistant ceramic coating and wear-resistant ceramic coating
CN108715987B (en) Method for improving bonding strength of thermal barrier coating
CN113151772A (en) Novel high-temperature corrosion-resistant thermal barrier coating with double ceramic layer structure and preparation method thereof
CN104032258A (en) Method And System For Die Compensation And Restoration Using High-velocity Oxy-fuel Thermal Spray Coating And Plasma Ion Nitriding
CN111057988A (en) Preparation method of reinforced ceramic three-dimensional constraint coating
CN112063958A (en) Reciprocating pump plunger coated with amorphous alloy coating and processing technology thereof
CN106191829B (en) Preparation method of micro-nano multi-scale structure on surface of medium carbon steel
CN112275593B (en) Method for improving coating microstructure
CN108531844B (en) Preparation method of rare earth oxide doped high-temperature oxidation resistant and wear-resistant coating for H13 steel surface protection
CN113355625A (en) NbC-reinforced high-entropy alloy-based composite coating and preparation method thereof
CN107299310A (en) A kind of preparation method for strengthening water pump vane Ceramic Coating Prepared By Plasma Spraying On The Surface
CN111962028A (en) EB-PVD/APS composite structure double-ceramic-layer thermal barrier coating and preparation method thereof
CN101285136A (en) Preparation method for porous titanium and porous titanium alloy
CN113186483B (en) Amorphous functional protective coating suitable for complex working conditions and preparation method thereof
CN110004393A (en) A kind of supersonic flame spraying technology preparation Y2O3The method of ceramic coating
CN104099608B (en) The method of Cu-Ag-Zn abradable seal coating is prepared in a kind of cold spraying
CN212223077U (en) Titanium alloy shaft part

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant