A kind of cr/crn/craln gradient coating and preparation method for anti-oxidation at high temperature

A gradient coating and anti-oxidation technology, which is applied in coating, metal material coating process, vacuum evaporation plating, etc., to achieve excellent high temperature oxidation resistance, protection of substrate oxidation, and easy composition

Active Publication Date: 2021-07-02
UNIV OF SCI & TECH BEIJING +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is no report on the application of Cr / CrN / CrAlN coating on heat-resistant steel

Method used

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  • A kind of cr/crn/craln gradient coating and preparation method for anti-oxidation at high temperature
  • A kind of cr/crn/craln gradient coating and preparation method for anti-oxidation at high temperature
  • A kind of cr/crn/craln gradient coating and preparation method for anti-oxidation at high temperature

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Put the 9-12% Cr heat-resistant steel substrate with a size of 7mm×7mm×1mm after sandblasting pretreatment on the surface into the vacuum coating equipment, and vacuumize it to less than 4.8×10 -6 pa, and then heat the substrate to 200°C. Open the inlet valve and fill with argon gas of 7 SCCM, and adjust the substrate bias voltage to -700V so as to remove the oxide layer on the substrate surface. Then adjust the substrate bias to -100V, turn on the DC power connected to the Cr target, and sputter the bottom layer of Cr at a power of 100W for 20 minutes, and the thickness of the bottom layer of Cr is 200nm. Then pass into the N of 7SCCM 2 , keep the Cr target power at 100W and sputter the CrN intermediate layer for 40min, and the thickness of the CrN intermediate layer is 200nm. Finally, turn on the DC power connected to the Al target, adjust the power of the Cr target to 40W, and the power of the Al target to 100W, and co-sputter the Cr-Al-N layer, and the thickness o...

Embodiment 2

[0022] The difference from Example 1 is that the CrN / CrAlN coating does not require sputtering of the Cr bottom layer, and the sputtering time of the CrN layer is 80 min. Depend on figure 2 (a) Scratch morphology of CrN / CrAlN coating and (b) Scratch morphology of Cr / CrN / CrAlN coating, it can be seen that the Lc1 (critical fracture load) of Cr / CrN / CrAlN coating after adding Cr underlayer is much larger Based on the Lc1 of CrN / CrAlN coating, that is, adding the Cr bottom layer can significantly improve the bonding ability of the coating and steel.

Embodiment 3

[0024] 800°C constant temperature oxidation experiment was carried out on 9-12% Cr heat-resistant steel and Cr / CrN / CrAlN coating, such as image 3 shown. The oxidation resistance of Cr / CrN / CrAlN coating at 800℃ is significantly stronger than that of 9-12% Cr heat-resistant steel.

[0025] It can be seen from Example 1, Example 2, and Example 3 that the Cr / CrN / CrAlN coating not only has good bonding ability with 9-12% Cr heat-resistant steel, but also has good high-temperature oxidation resistance.

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Abstract

The invention discloses a Cr / CrN / CrAlN gradient coating for anti-oxidation at high temperature and a preparation method thereof, belonging to surface engineering technology. Cr / CrN / CrAlN coating was deposited on the surface of 9-12% Cr heat-resistant steel, and the Cr / CrN / CrAlN coating was obtained by direct-current reactive co-sputtering of Cr target and Al target. The substrate temperature was 150-200°C, and Ar and N 2 Microcomputer control is adopted, the flow rates are 5-7SCCM (standard cubic meter per minute) and 6-8SCCM respectively, and the working air pressure is 5-10mtorr. In order to improve the bonding force between the coating and the substrate, a Cr bottom layer is selected, and a negative bias voltage of 100-150V is applied to the substrate. The bottom layer of the obtained coating is a Cr layer, the middle layer is a CrN layer, and the outer layer is a CrAlN layer. The main product of the coating after oxidation in air at 600-800°C is Al 2 o 3 . High temperature oxidation experiments show that Cr / CrN / CrAlN coating has good high temperature oxidation resistance. The application of the invention can remarkably improve the high-temperature oxidation resistance of the heat-resistant steel.

Description

technical field [0001] The invention belongs to surface engineering technology, in particular to a Cr / CrN / CrAlN protective coating for high-temperature oxidation resistance of heat-resistant steel and a preparation method thereof. Background technique [0002] 9–12% Cr martensitic heat-resistant steel is widely used in ultra-supercritical power plants because of its high thermal conductivity, low thermal expansion coefficient and low thermal fatigue susceptibility. Document 1: Research by Dr. Viswanathan in the Journal of Materials Engineering and Performance (Journal of Materials Engineering and Performance, 15, 3, (2006)) pointed out that the service temperature limit of this type of heat-resistant steel is 620°C. One of the limiting links is the poor oxidation resistance of heat-resistant steels at higher temperatures. At present, in order to use it under high steam parameters (630°C), the main method is to increase the Cr content in heat-resistant steel so that a large ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C14/34C23C14/02C23C14/14C23C14/06
CPCC23C14/3464C23C14/025C23C14/14C23C14/0641C23C14/0036
Inventor 杨文晟郭汉杰陈胜吉
Owner UNIV OF SCI & TECH BEIJING
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