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Method for preparing Nb/NbCr2-based high-temperature alloy surface anti-oxidation composite coating

A technology of superalloy and composite coating, applied in metal material coating process, coating, solid-state diffusion coating, etc., can solve the problem of room temperature plasticity and toughness decline, anti-oxidation performance, and insufficient bonding force between coating and substrate and other problems, to achieve the effect of improving high temperature oxidation resistance and good peeling properties

Inactive Publication Date: 2010-09-08
NANCHANG HANGKONG UNIVERSITY
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  • Application Information

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Problems solved by technology

However, the problem of Nb-based alloy high-temperature oxidation-resistant coatings is that the bonding force between the coating and the substrate is not strong enough, and the expansion coefficient does not match, which will make the coating prone to peeling or cracking when subjected to thermal fatigue or thermal shock, thereby significantly reducing The service life of Nb-based alloys and the reliability of the coating, so it is necessary to add a certain amount of modifying elements to the silicide coating to improve its toughness and high temperature oxidation resistance
But for the Laves phase NbCr rich in soft second phase Nb 2 The coating preparation of the base alloy has not been reported yet, which is good for fully utilizing Nb to toughen the Laves phase NbCr 2 The effect is unfavorable
Although He et al. used the embedding infiltration method in NbCr rich in soft second phase Cr 2 The coating prepared on the surface of the base alloy can greatly improve the high temperature oxidation resistance of the alloy at 1100°C, but the oxidation resistance of the coating at 1200°C is still unknown; and the coating preparation process is embedded and infiltrated at a high temperature of 1000°C for 12 hours , which inevitably causes the grain growth of the matrix alloy, resulting in a decrease in ductility and toughness at room temperature

Method used

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  • Method for preparing Nb/NbCr2-based high-temperature alloy surface anti-oxidation composite coating
  • Method for preparing Nb/NbCr2-based high-temperature alloy surface anti-oxidation composite coating
  • Method for preparing Nb/NbCr2-based high-temperature alloy surface anti-oxidation composite coating

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Experimental program
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Effect test

Embodiment 1

[0026] The present invention is realized like this, it is characterized in that method step is:

[0027] (1) Preparation of Si-Al coating

[0028] ①The penetrating agent consists of 8Si, 6Al, 1NaF, 65Al in mass fraction wt.%. 2 o 3 composition;

[0029] ② After the penetrating agent is mixed, the rotation speed is 300r / m, and it is refined by ball milling for 2 hours;

[0030] ③Then bury the infiltrated sample in a corundum crucible filled with an infiltrating agent, cover the lid, seal it with a high-temperature adhesive, and dry it at 100°C for 2 hours;

[0031] ④Put it in a high-temperature electric furnace and keep it at 800°C for 2 hours. The heating rate is about 16°C / min. After the heat preservation is over, the sample is cooled to room temperature with the furnace, and the surface is taken out and cleaned to obtain a Si-Al co-infiltration sample;

[0032] (2) Preparation of Al(OH) by Sol-gel method 3 sol

[0033] ① Prepare 0.1mol / L Al(NO 3 ) 3 solution;

[003...

Embodiment 2

[0041] The present invention is realized like this, it is characterized in that method step is:

[0042] (1) Preparation of Si-Al coating

[0043] ① The penetrating agent consists of 20Si, 15Al, NaF, 85Al in mass fraction wt.%. 2 o 3 composition;

[0044] ② After the penetrating agent is mixed, the rotation speed is 500r / m, and it is refined by ball milling for 10 hours;

[0045] ③Then bury the infiltrated sample in a corundum crucible filled with an infiltrating agent, cover the lid, seal it with a high-temperature adhesive, and dry it at 100°C for 2 hours;

[0046] ④Put it in a high-temperature electric furnace and keep it at 1200°C for 2 hours. The heating rate is about 16°C / min. After the heat preservation is over, the sample is cooled to room temperature with the furnace, and the surface is taken out and cleaned to obtain a Si-Al co-infiltration sample;

[0047] (2) Preparation of Al(OH) by Sol-gel method 3 sol

[0048] ① Prepare 0.22mol / L Al(NO 3 ) 3 solution;

...

Embodiment 3

[0056] The present invention is realized like this, it is characterized in that method step is:

[0057] (1) Preparation of Si-Al coating

[0058] ① The penetrating agent consists of 12Si, 10Al, 5NaF, 70Al in mass fraction wt.%. 2 o 3 composition;

[0059] ② After the penetrating agent is mixed, the rotation speed is 400r / m, and it is refined by ball milling for 5 hours;

[0060] ③Then bury the infiltrated sample in a corundum crucible filled with an infiltrating agent, cover the lid, seal it with a high-temperature adhesive, and dry it at 100°C for 2 hours;

[0061] ④Put it in a high-temperature electric furnace at 1100°C for 2 hours, and the heating rate is about 16°C / min. After the heat preservation is over, the sample is cooled to room temperature with the furnace, and the surface is taken out and cleaned to obtain a Si-Al co-infiltration sample;

[0062] (2) Preparation of Al(OH) by Sol-gel method 3 sol

[0063] ① Prepare 0.15mol / L Al(NO 3 ) 3 solution;

[0064] ...

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Abstract

The invention discloses a method for preparing an Nb / NbCr2-based high-temperature alloy surface anti-oxidation composite coating, which is characterized by comprising the following steps of: (1) preparing a Si-Al coating; (2) preparing Al(OH)3 sol by the sol-gel method; and (3) performing hot pressing. The method has the advantages that: (1) the coating is closely combined with a base and is compact so as to form a composite structure with an outer Al2O3 layer and an inner Si, Al, Cr and Nb diffusion layer; (2) the oxide film strips off seriously at the beginning of the oxidation at the temperature of 1,200 DEG C so as to cause disastrous oxidation; (3) the composite coating has the optimum effect of preventing the oxide film from stripping, namely only 0.049mg of the oxide film per square millimeter strips off after the oxidation is carried out ten times for 100 hours at the temperature of 1,100 DEG C, and particularly, only 0.13mg of the oxide film per square millimeter strips off at the temperature of 1,200 DEG C and only a weight of 3.38mg / cm2 is increased; therefore, the high temperature oxidation resistance of the Cr-50Nb alloy is greatly improved.

Description

technical field [0001] The invention relates to an anti-oxidation composite coating on the surface, in particular to a preparation method for the anti-oxidation composite coating on the surface of an Nb / NbCr2-based superalloy. Background technique [0002] Laves Phase NbCr Formed by Alloying Element Cr and Refractory Metal Nb 2 It is an important class of intermetallic compounds, which not only has an appropriate specific gravity and a high melting point, but also has a yield strength as high as 600MPa at 1200°C. These properties make Laves phase NbCr 2 It has become a new type of high-temperature structural material with great application potential in advanced aero-engine hot-end components. Therefore, it has aroused great interest of domestic and foreign research scholars. [0003] However, the Laves phase NbCr 2 It has a topological close-packed structure and a complex crystal structure, which makes this kind of compound very brittle at room temperature, which serious...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C10/52
Inventor 鲁世强郑海忠
Owner NANCHANG HANGKONG UNIVERSITY
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