Method for preparing composite coating by adopting multi-stage pack cementation aluminizing in combination with micro-arc oxidation

A technology of micro-arc oxidation and composite coating, which is applied in the direction of coating, superimposed layer plating, surface reaction electrolytic coating, etc. There are reports and other issues to achieve good thermal corrosion resistance, good bonding, and the effect of reducing substrate stress

Active Publication Date: 2017-05-10
GUANGXI UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Rare earth salt additives have a great influence on the performance of micro-arc oxidation ceramic films. At present, the relevant research mainly focuses on Al and Mg alloys. Corrosion properties are rarely reported

Method used

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  • Method for preparing composite coating by adopting multi-stage pack cementation aluminizing in combination with micro-arc oxidation
  • Method for preparing composite coating by adopting multi-stage pack cementation aluminizing in combination with micro-arc oxidation
  • Method for preparing composite coating by adopting multi-stage pack cementation aluminizing in combination with micro-arc oxidation

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Effect test

Embodiment 1

[0030] A preparation method of multi-stage embedded aluminizing combined with composite additive micro-arc oxidation on the surface of niobium alloy includes the following operation steps:

[0031] 1. Pretreatment: The base material is niobium alloy C103, and its chemical composition is: Hf 10.0, Ti 1.30, Zr 0.34, W 0.34, Ta 0.30, C 0.005, N 0.014, O 0.013, Nb balance (wt.%), After polishing step by step, ultrasonically clean with acetone for 12 minutes and blow dry;

[0032] 2. Multi-stage embedded aluminizing treatment: firstly, the aluminizing agent is prepared according to the following weight percentages: aluminizing agent aluminum powder 10wt%, activator sodium fluoride powder 3wt%, and filler alumina powder 87wt%, and then mixed with a ball mill , Then seal the fully mixed aluminizing agent and the substrate together in a ceramic crucible, and finally place it in a vacuum tube furnace and evacuate to 3.5×10 -2 Pa, at a heating rate of 10°C / min to 120°C for 1 hour, 300°C for ...

Embodiment 2

[0035] 1. Pretreatment: The base material is niobium alloy C103, and its chemical composition is: Hf 10.0, Ti 1.30, Zr 0.34, W 0.34, Ta 0.30, C 0.005, N 0.014, O 0.013, Nb balance (wt.%), After polishing step by step, ultrasonically clean with acetone for 15 minutes and blow dry;

[0036] 2. Multi-stage embedded aluminizing treatment: firstly, the aluminizing agent is prepared according to the following weight percentages: aluminizing agent aluminum powder 11wt%, activator sodium fluoride powder 4wt% and filler alumina powder 85wt%, and then mixed with a ball mill , Then the fully mixed aluminizing agent and the substrate are sealed in a ceramic crucible, and finally placed in a vacuum tube furnace, and evacuated to 1.3×10 -1 Pa, at a heating rate of 10°C / min to 150°C for 1 hour, 350°C for 2 hours, 940°C for 4 hours, and then at a cooling rate of 10°C / min to 400°C and then cooled to room temperature with the furnace to obtain NbAl 3 Aluminized niobium alloy for aluminized layer;

...

Embodiment 3

[0039] 1. Pretreatment: The base material is niobium alloy C103, and its chemical composition is: Hf 10.0, Ti 1.30, Zr 0.34, W 0.34, Ta 0.30, C 0.005, N 0.014, O 0.013, Nb balance (wt.%), After polishing step by step, ultrasonically clean with acetone for 15 minutes and blow dry;

[0040] 2. Multi-stage embedded aluminizing treatment: firstly, the aluminizing agent is prepared according to the following weight percentages: 9wt% of aluminizing agent aluminum powder, 2wt% of activator sodium fluoride powder and 89wt% of filler alumina powder, and then mixing with a ball mill , Then the fully mixed aluminizing agent and the base material are sealed together in a ceramic crucible, and finally placed in a vacuum tube furnace, evacuated to 4.0Pa, and heated to 120°C at a temperature increase rate of 10°C / min and held for 1h, 300°C Insulate for 2h, 940℃ for 3h, then at a cooling rate of 10℃ / min to 400℃, then cool to room temperature with the furnace to obtain NbAl 3 Aluminized niobium a...

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Abstract

The invention discloses a method for preparing a composite coating by adopting multi-stage pack cementation aluminizing in combination with micro-arc oxidation and belongs to the technical field of high-temperature protective coatings. A continuous and smooth NbAl3 aluminized layer is obtained firstly on a substrate with a multi-stage pack cementation aluminizing technology; a micro-arc oxidation electrolyte is regulated by adding film-forming agent sodium fluoride, modifier sodium tungstate, stabilizer EDTA-2Na and rare-earth salt yttrium nitrate; and a uniform and regular porous Al2O3 ceramic film layer is prepared on the NbAl3 aluminized layer, and the Al2O3/NbAl3 composite coating is obtained. The Al2O3/NbAl3 composite coating has the characteristics of good bonding performance, uniform coating and excellent high-temperature hot corrosion resistance, the coating with different thicknesses can be obtained by controlling pack cementation aluminizing time and temperature as well as the electrolyte and electrical parameters of the micro-arc oxidation, the process is simple, and the controllability is high.

Description

Technical field [0001] The invention belongs to the technical field of high-temperature protective coatings, and relates to a method for preparing a composite coating with multi-stage embedded aluminizing combined with micro-arc oxidation. Background technique [0002] High-temperature protective coatings are mainly used in the hot end parts of gas turbines in the aerospace and modern energy industries. Niobium (Nb) has a high melting point (2468°C) and a moderate density (8.6g / cm) 3 ), high-temperature specific strength, excellent high-temperature mechanical properties and processing properties, niobium alloy is one of the important candidates for high-temperature structural materials. But the oxidation resistance of niobium alloy is poor, so it is very important to apply a protective coating on the surface of niobium alloy. Micro-arc oxidation can form a ceramic film with high hardness, wear resistance and corrosion resistance in situ on the surface of the material through the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C10/48C23C28/00C25D11/26
CPCC23C10/48C23C28/321C23C28/322C23C28/345C25D11/026C25D11/26
Inventor 李伟洲黄祖江董婉冰童庆蒋智秋钱堃陈泉志
Owner GUANGXI UNIV
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