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Laser remelting post-treatment method for preparing MCrAlY coating resistant to high-temperature oxidation corrosion through supersonic flame thermal spraying

A supersonic flame and anti-high temperature oxidation technology, which is applied in coating, metal material coating process, fusion spraying, etc., can solve the problems of difficult coating formation, low oxide content, high cost, etc., and achieve a flat TGO growth curve , Metastable phase structure reduction, growth rate reduction effect

Pending Publication Date: 2021-06-11
NANJING INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Patent Publication No. CN10699682A discloses a method of preparing a cavitation-resistant coating by using a composite process of cold spraying and laser remelting. Under the high-density energy of the laser, the surface of the cermet coating is re-melted to form a new microstructure Structure, the performance of this type of coating is enhanced after cooling, and the cavitation resistance of the coating is greatly improved. However, the cost of preparing the coating by cold spraying in this process is very high, and the post-laser remelting treatment will increase The preparation cost of the coating, in addition, if some coatings with high particle critical velocity are prepared by cold spraying technology, the formation of the coating is more difficult
However, this patent does not involve the laser remelting post-treatment process of MCrAlY protective coatings prepared by supersonic flame spraying or MCrAlY high-temperature corrosion-resistant protective coatings prepared by the new active combustion high-velocity gas spraying technology (AC-HVAF)
[0007] The MCrAlY coating prepared by active combustion high velocity gas spraying technology (AC-HVAF) has extremely low oxide content, high interfacial bonding strength and high coating deposition efficiency, and after high temperature oxidation, the surface of MCrAlY coating can be A relatively continuous, single and dense thermally grown oxide layer (TGO) with alumina as the main phase is formed, but as the high temperature oxidation service progresses, the TGO of the coating needs to be further purified, and the TGO growth rate curve is still steep , the bonding force of TGO / coating interface is not high, and the TGO protective layer of the coating is easier to peel off

Method used

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  • Laser remelting post-treatment method for preparing MCrAlY coating resistant to high-temperature oxidation corrosion through supersonic flame thermal spraying
  • Laser remelting post-treatment method for preparing MCrAlY coating resistant to high-temperature oxidation corrosion through supersonic flame thermal spraying
  • Laser remelting post-treatment method for preparing MCrAlY coating resistant to high-temperature oxidation corrosion through supersonic flame thermal spraying

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Effect test

Embodiment 1

[0027] (1) Sandblasting coarsening: white corundum particle size: 120 microns, sandblasting pressure: 0.2-0.8MPa.

[0028] (2) Coating preparation (active combustion high-speed gas spraying technology AC-HVAF): air pressure is 0.7-0.8MPa, air flow rate is ~300 liters / min; propane fuel pressure is 0.65-0.8MPa, propane gas flow rate is ~450 L / min; powder feeding gas N 2 The pressure is ~0.1MPa, the powder feeding gas is N 2 The flow rate is ~60 liters / minute; the spraying distance is 250~400mm; the powder feeding rate is 50-200g / min; the moving speed of the spray gun is 10-20mm / s; the number of spraying times is 6~20 times. The MCrAlY coating composition adopts Ni22Co17Cr12Al0.5Hf0.5Y0.4Si, and the particle size distribution of the powder is 63±5 microns.

[0029] (3) Laser remelting post-processing: The laser is incident vertically or at a certain angle, the laser power is 150-200W, the geometric shape of the laser spot is a rectangle of 2mm×5mm, and the moving speed of the rob...

Embodiment 2

[0031] (1) Sandblasting coarsening: white corundum particle size: 120 microns, sandblasting pressure: 0.2-0.8MPa.

[0032] (2) Coating preparation (active combustion high-speed gas spraying technology AC-HVAF): air pressure is 0.7-0.8MPa, air flow is ~300 liters / minute; propane fuel pressure is 0.65-0.8MPa, propane gas flow is ~450 L / min; powder feeding gas N 2 The pressure is ~0.1MPa, the powder feeding gas is N 2 The flow rate is ~60 liters / minute; the spraying distance is 250~400mm; the powder feeding rate is 50-200g / min; the moving speed of the spray gun is 10-20mm / s; the number of spraying times is 6~20 times. The composition of the MCrAlY coating is Ni23Co20Cr8.5Al0.6Y4.0Ta, and the particle size distribution of the powder is 37±5 microns.

[0033] (3) Laser remelting post-processing: The laser is incident vertically or at a certain angle, the laser power is 150-200W, the geometric shape of the laser spot is a rectangle of 2mm×5mm, and the moving speed of the robot is ...

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Abstract

The invention discloses a method for post-treating a MCrAlY coating resistant to high-temperature oxidation corrosion through supersonic flame thermal spraying by adopting a laser remelting method. The method comprises the following steps: performing sand blasting coarsening on a high-temperature alloy substrate material, performing ultrasonic cleaning by using a mixed solution of acetone and absolute ethyl alcohol, thoroughly drying a workpiece, and then fixing the workpiece to a rotary worktable; preparing the MCrAlY coating resistant to high-temperature oxidation corrosion by adopting the supersonic flame thermal spraying process, and enabling the thickness of the coating to be in a range of 200-500 microns; and carrying out post-treatment on the prepared MCrAlY coating by adopting the laser remelting process. According to the method, second phase distribution in the obtained coating is more uniform so as to improve comprehensive mechanical properties such as strength and toughness, and the bonding strength between the coating and the substrate high-temperature alloy is improved, so that the coating and the substrate high-temperature alloy are metallurgically bonded. After high-temperature oxidation service, a thermal growth oxidation layer is formed on the surface of the coating, and a single, compact, continuous and stable alpha-Al2O3 protective film is formed on the surface of the coating.

Description

technical field [0001] The invention relates to the field of thermal spraying, in particular to a laser remelting post-treatment method for preparing a high-temperature oxidation-corrosion-resistant MCrAlY coating by supersonic flame thermal spraying. Background technique [0002] Thermal spraying technology is a process in which powder materials are sent to a heat source (plasma, laser, arc, flame, etc.) It has the advantages of faster speed, higher productivity and wide adaptability. However, the thermal spray coating has a certain porosity, the structure of the coating is not very uniform, the coating and the substrate are mechanically bonded, and the strength is poor, which seriously affects the application of the thermal spray coating. [0003] Supersonic flame is a high-temperature, high-speed combustion flame flow produced by burning propane, propylene and other hydrocarbon gases or hydrogen and high-pressure oxygen in a combustion chamber or in a special nozzle. The...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C4/18C23C4/129C23C4/073C23C4/02
CPCC23C4/18C23C4/129C23C4/073C23C4/02
Inventor 韩玉君王宁李晓泉初雅杰陈宇谢静玲李浩然
Owner NANJING INST OF TECH