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Preparation method of thermal barrier coating on aluminum, magnesium alloy and composite material surface

A technology of composite materials and thermal barrier coatings, applied in coatings, electrolytic coatings, anodic oxidation, etc., can solve problems such as poor bonding between ceramic layers and aluminum substrates, large differences in thermal expansion coefficients, and difficult control of coating components. Achieve the effects of good insulation, controllable thickness and excellent heat insulation effect

Active Publication Date: 2011-12-14
XIAN KANGBO NEW MATERIAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Thermal spraying technology is not limited by the substrate material, the operation process is flexible and convenient, and the coating thickness is controllable, but the bonding force between the sprayed ceramic layer and the aluminum substrate is poor, and the ceramics are easy to crack and peel off after operating at high temperature
The microstructure of the thermal barrier coating prepared by EB-PVD method has good strain tolerance, which greatly improves the thermal fatigue resistance of the coating. However, the deposition rate of EB-PVD is low, the equipment cost is expensive, and the element vapor Due to the influence of pressure, it is difficult to control the composition of the coating, the substrate parts need to be heated, and the sample size cannot be too large, all of which limit the industrialization of this method to a large extent.
Although the application of hard anodic oxidation, ion plating, chemical or physical vapor deposition TiN (or CrN) coating technology can improve its surface performance to a certain extent, it is still insufficient in the face of service conditions under high speed and high contact stress. , but also bring some environmental problems
In addition, using the heat insulation and reducing stress concentration of the ceramic layer, it is also a common choice in this field to spray a layer of firm heat insulation ceramics on the surface of the engine components, but the sprayed ceramic layer has a layer between the aluminum substrate and the aluminum base. Obvious interface, large difference in thermal expansion coefficient, not resistant to thermal shock, easy to fall off in thermal cycle

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The plasma electrolyte is a silicate and phosphate system. Add a pH regulator to the deionized water to adjust the pH value to 9-10, then add sodium silicate and sodium phosphate, and take sodium silicate according to the ratio of weight to total volume. 10g / L, sodium phosphate 15g / L, to prepare plasma electrolyte. Put the alloy sample in the electrolyte, connect the positive electrode of the power supply, and connect the stainless steel to the negative electrode of the power supply, and use the constant current method to control the micro-arc oxidation process, and the current density is 3A / dm 2 , oxidation time 10min. From the experimental phenomenon, the reaction is stable. The starting voltage is 183V and the ending voltage is 270V. As the oxidation time prolongs, the sparks turn from bright white to orange, and there is a very weak popping sound during the experiment. After oxidation, a layer of light gray-white smooth and dense plasma electrolytic oxidation cer...

Embodiment 2

[0022] The plasma electrolyte is a silicate and phosphate system. According to the ratio of weight to total volume, potassium silicate is 20g / L, potassium phosphate is 15g / L, and the current density is 5A / dm 2 , oxidation time 20min. The starting voltage is 145V, the ending voltage is 295V, and the other operations are the same as the previous example. Due to the high electrolyte concentration and long oxidation time, the SEM topography of the coating section shows that the resulting film is thicker than the previous example but the roughness is increased. Electrophoretic deposition electrolyte is Zr(OH) 2 Colloidal electrolyte, according to the ratio of weight to total volume, take potassium zirconate 15g / L, potassium hydroxide 15g / L, current density 8A / dm 2 ,, the processing time is 15min, and the other operations are the same as the previous example. From the plasma electrolytic oxidation-electrophoretic deposition composite film surface and cross-sectional scanning elec...

Embodiment 3

[0024] The plasma electrolytic oxidation electrolyte is a silicate and phosphate system. According to the ratio of weight to total volume, sodium silicate is 20g / L, sodium phosphate is 15g / L, and the current density is 3A / dm 2 , the oxidation time is 2min, the pH value is controlled at 8-12, the arc starting voltage is 175V, and the ending voltage is 192V, and the rest of the operations are the same as in the first embodiment. The electrophoretic deposition electrolyte is formed by the reaction of 20g / L sodium zirconate and 20g / L sodium hydroxide, and the deposition current density is 8A / dm 2 , electrophoresis time 30min. The pH value is controlled at 3 to 7, and the rest of the operations are the same as in Example 1.

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PUM

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Abstract

The invention provides a preparation method of a thermal barrier coating on the surface of an aluminum-magnesium alloy and a composite material of the alloy. The preparation method is characterized in that the thermal barrier coating on the surface of the aluminum-magnesium alloy and the composite material of the alloy is prepared by carrying out electrolytic oxidation on the surface of the aluminum-magnesium alloy and the composite material of the alloy with a silicatic and phosphatic system plasma electrolyte to form a film medium, and carrying out electrophoretic deposition on the plasma electrolytic oxidation film (the film medium) with an electrophoretic deposition electrolyte. A plasma electrolytic oxidation-electrophoresis composite ceramic layer obtained with the preparation method of the invention, which has the advantages of smooth surface, firm combination, controllable thickness, densification and less aperture, good thermal insulation and thermal shock resistance, is suitable for workpieces with various dimensions and surfaces of complicated shapes.

Description

technical field [0001] The invention belongs to the technical field of material surface coating and relates to a preparation method of a thermal barrier coating on the surface of aluminum, magnesium alloys and composite materials. Background technique [0002] As non-ferrous metals with low density and light weight, aluminum, magnesium alloys and their composite materials have been widely used in many parts and components of automobiles, aviation gas engines, and military engine equipment in recent years, providing a direction for the lightweight development of products. However, due to the low high-temperature strength and creep properties of aluminum and magnesium alloys, the application of aluminum, magnesium alloys and their composite materials in high temperature (150-350°C) occasions is limited, making it difficult to meet the requirements of high temperature, high pressure and high temperature. Complex working conditions such as corrosive media. For this reason, in t...

Claims

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Application Information

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IPC IPC(8): C25D11/04C25D11/30C25D13/02
Inventor 李建平王萍郭永春杨忠李艳
Owner XIAN KANGBO NEW MATERIAL TECH
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