A rear earth lutetium silicate composite environmental barrier coating and a preparing method thereof

A lutetium silicate and environmental barrier technology is applied in the field of rare earth lutetium silicate composite environmental barrier coating on the surface of SiC/SiC material and its preparation, which can solve the problem that the use of environmental barrier coating cannot be satisfied, and the coating is prone to microcracks. , poor process controllability and other problems, to achieve good water vapor corrosion resistance, excellent water vapor resistance, and reduce thermal stress.

Inactive Publication Date: 2018-06-29
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traditional coating preparation methods include brush coating, chemical vapor deposition, slurry dipping, sol-gel, etc. Although these methods are simple and feasible to prepare and low in cost, they have poor process controllability, produce toxic gases, and the prepared coating Defects such as thinner, lower bonding strength; unable to meet the environmental barrier coating used in high temperature, high pressure, high speed erosion and corrosion environment
Atmospheric plasma spraying is the most widely used and most mature technology in the third generation of environmental barrier coatings, but this technology also has some disadvantages. Due to the spraying in the atmospheric environment, the temperature of the substrate is not high, and the coating is deposited on the surface of the substrate instantly. The temperature difference between the substrate and the substrate is large, and the coating is prone to micro-cracks due to thermal stress

Method used

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  • A rear earth lutetium silicate composite environmental barrier coating and a preparing method thereof
  • A rear earth lutetium silicate composite environmental barrier coating and a preparing method thereof
  • A rear earth lutetium silicate composite environmental barrier coating and a preparing method thereof

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Embodiment 1

[0045] Take the SiC / SiC material with a size of 20mm×20mm×4.0mm as the substrate 2, clean it with acetone, ethanol, and ultrasonic for 20 minutes in sequence, and then dry it in an oven at 110°C for 2 hours; the cleaned and dried SiC / SiC substrate Installed on the jig placed in the vacuum chamber 1, evacuated to 0.3Mpa, backfilled with argon to 50Mpa, and then evacuated to 1.2Mpa.

[0046] The parameters for preparing the mullite layer are: voltage 80V, current 800A, flow rate of argon gas in the plasma gas is 85L / min, hydrogen gas in the plasma gas is 10L / min, powder feeding amount is 15g / min, and the spraying distance is 800mm; The temperature is controlled at 1100° C.; the thickness of the mullite layer is 150 μm.

[0047] Preparation of Lu with a mass ratio of 6:4 2 Si 2 o 7 and Lu 2 SiO 5 The parameters of the surface layer are: voltage 60V, current 700A, flow rate of argon gas in the plasma gas is 100L / min, hydrogen gas in the plasma gas is 10L / min, powder feeding r...

Embodiment 2

[0052] Take the SiC / SiC material with a size of 20mm×20mm×4.0mm as the substrate 2, clean it with acetone, ethanol, and ultrasonic for 20 minutes in sequence, and then dry it in an oven at a temperature of 110°C for 2 hours. The cleaned and dried SiC / SiC substrate Installed on the jig placed in the vacuum chamber 1, evacuated to 0.3Mpa, backfilled with argon to 50Mpa, and then evacuated to 2Mpa.

[0053] The parameters for preparing the mullite layer are: voltage 90V, electric current 900A, argon gas flow in the plasma gas is 95L / min, hydrogen in the plasma gas is 15L / min, powder delivery rate is 10g / min, and the spraying distance is 900mm; The temperature is controlled at 1100° C.; the thickness of the mullite layer is 150 μm.

[0054] Preparation of Lu with a mass ratio of 6:4 2 Si 2 o 7 and Lu 2 SiO 5 The parameters of the surface layer are: voltage 70V, current 800A, flow rate of argon gas in the plasma gas is 120L / min, hydrogen gas in the plasma gas is 20L / min, powde...

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Abstract

A rear earth lutetium silicate composite environmental barrier coating and a preparing method thereof are disclosed. The composite environmental barrier coating includes a SiC / SiC matrix, a mullite layer and a composite surface layer consisting of Lu2Si2O7 and Lu2SiO5 in a mass ratio of 6:4. The preparing method combining plasma spraying and physical vapor deposition is adopted, and mullite powderhaving a particle size of 18-58 [mu]m and Lu2Si2O7-Lu2SiO5 composite powder having a particle size of 62-105 [mu]m are adopted as raw materials to prepare the mullite layer on the SiC / SiC matrix andthe composite surface layer on the mullite layer in order. The coating prepared by the method has good resistance to water oxygen corrosion at 1723 K, effectively retards generation of cracks and effectively avoids oxidation and performance degradation of the SiC / SiC matrix at high temperatures.

Description

technical field [0001] The invention relates to the field of design and preparation of a coating structure; specifically, it mainly relates to a rare earth lutetium silicate composite environmental barrier coating on the surface of a SiC / SiC material and a preparation method thereof. Background technique [0002] With the development of the aviation and defense industry, people's demand for high-efficiency, high-thrust-to-weight ratio aero-engines is becoming stronger and stronger, which without exception puts forward more stringent requirements on the hot-end parts of aero-engines, such as higher temperature and faster speed , higher pressure, harsh corrosive environment, etc. Nickel-based superalloys have severely limited their application in reliable high-temperature structural materials due to their limited temperature resistance (the limit service temperature is about 1150°C) and their own high-density characteristics. urgent needs. The search for lightweight, high-st...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B41/89
CPCC04B41/009C04B41/4533C04B41/52C04B41/89C04B2235/9669C04B35/565C04B41/5031C04B41/5045
Inventor 许越胡寻寻
Owner BEIHANG UNIV
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