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Composite gradient hydrogen-resistant coating for high-temperature evacuated collector tube and preparation method thereof

A vacuum heat collector tube and coating technology, applied in coating, chemical instruments and methods, metal material coating process, etc., can solve the problem of high requirements for coating preparation process and equipment, reduced hydrogen resistance effect of coating, and unfavorable large-scale production. Production and other problems, to achieve the effect of improving the ability of preventing hydrogen penetration and corrosion resistance, high density and controllable thickness

Active Publication Date: 2014-07-02
GRIMAT ENG INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the main methods for preparing hydrogen-resistant coatings are: hot-dip coating, flame spraying, vacuum plasma spraying, chemical vapor deposition, etc. The main problem is that there is a large mismatch between the thermal expansion coefficient of the coating material and the substrate. After thermal shock, there is a large thermal stress between the coating and the substrate, which causes the separation of the coating and the substrate, resulting in a decrease in the hydrogen barrier effect of the coating.
Moreover, the preparation process and equipment requirements of some coatings are relatively high, and the production cost is relatively high, which is not conducive to mass production

Method used

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  • Composite gradient hydrogen-resistant coating for high-temperature evacuated collector tube and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1. The surface of the austenitic 316L stainless steel sample was polished with 300#, 600# and 1200# SiC water abrasive paper, sandblasted, put into acetone solution for ultrasonic cleaning for 15 minutes, and dried;

[0031] 2. Prepare Ni-Cr-Al intermediate transition coating (Cr content is 25wt%, Al content is 5wt%, and the rest is Ni) on the surface of stainless steel by low-pressure plasma spraying technology; the specific process parameters are: current 500A, voltage 65V, H 2 The flow rate is 10L / min, the Ar flow rate is 50L / min, the chamber pressure is 4000Pa, the spraying speed is 4mm / s, and the spraying distance is 100mm.

[0032] 3. Put the sample prepared by low-pressure plasma spraying into a vacuum furnace after ultrasonic cleaning, seal it, vacuumize it, the pressure is <10Pa, feed argon gas, the pressure is 100000Pa, then vacuumize, and cycle twice;

[0033] 4. Turn off the argon gas, pass the hydrogen gas, the pressure is 100000Pa, start heating, and set t...

Embodiment 2

[0038] 1. The surface of the austenitic 316L stainless steel sample was polished with 300#, 600# and 1200# SiC water abrasive paper, sandblasted, put into acetone solution for ultrasonic cleaning for 15 minutes, and dried;

[0039] 2. Prepare Ni-Cr-Al intermediate transition coating (Cr content is 25wt%, Al content is 5wt%, and the rest is Ni) on the surface of stainless steel by low-pressure plasma spraying technology; the specific process parameters are: current 550A, voltage 65V, H 2 The flow rate is 20L / min, the Ar flow rate is 60L / min, the chamber pressure is 4000Pa, the spraying speed is 4mm / s, and the spraying distance is 100mm.

[0040] 3. Put the sample prepared by low-pressure plasma spraying into a vacuum furnace after ultrasonic cleaning, seal it, vacuumize it, the pressure is <10Pa, feed argon gas, the pressure is 100000Pa, then vacuumize, and cycle twice;

[0041] 4. Turn off the argon gas, pass the hydrogen gas, the pressure is 100000Pa, start heating, and set t...

Embodiment 3

[0046] 1. The surface of the austenitic 316L stainless steel sample was polished with 300#, 600# and 1200# SiC water abrasive paper, sandblasted, put into acetone solution for ultrasonic cleaning for 15 minutes, and dried;

[0047] 2. Prepare Ni-Cr-Al intermediate transition coating (Cr content is 25wt%, Al content is 5wt%, and the rest is Ni) on the surface of stainless steel by low-pressure plasma spraying technology; the specific process parameters are: current 700A, voltage 60V, H 2 The flow rate is 15L / min, the Ar flow rate is 80L / min, the chamber pressure is 4000Pa, the spraying speed is 4mm / s, and the spraying distance is 100mm.

[0048] 3. Put the sample prepared by low-pressure plasma spraying technology into a vacuum furnace after ultrasonic cleaning, seal it, vacuumize it, the pressure is <10Pa, feed argon gas, the pressure is 100000Pa, then vacuumize, and cycle twice;

[0049] 4. Turn off the argon gas, pass the hydrogen gas, the pressure is 100000Pa, start heating...

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Abstract

The invention discloses a composite gradient hydrogen-resistant coating for a high-temperature evacuated collector tube and a preparation method thereof. The preparation method comprises the following steps of carrying out Ni-Cr-Al transition layer preparation by a low-pressure plasma spraying device under the conditions of current of 300-800A, voltage of 40-100V, H2 flow of 5-100L / min, Ar flow of 5-100L / min, chamber pressure of 1000-10000Pa, a spraying speed of 1-20mm / s and a spraying distance of 10-100mm, putting a cleaned sample into a quartz glass tube, carrying out sealing, carrying out vacuum-pumping until pressure is <10Pa, feeding argon into the quartz glass tube until pressure is 100000Pa, carrying out vacuum-pumping, carrying out circulation twice, stopping argon feeding, feeding hydrogen into the quartz glass tube until pressure is 100000Pa, carrying heating under the condition of a preset furnace temperature of 500-1200 DEG C, carrying out heating in water bath having a temperature of 5-60 DEG C when the furnace temperature is in a range of 500-1200 DEG C, feeding H2 into H2O and then into a reaction zone to provide low-oxygen partial pressure of 10<-24> to 10<-16>Pa, and keeping the temperature for 1-20h under the conditions of the furnace temperature of 500-1200 DEG C and the water-bath temperature of 0-60 DEG C to obtain the Al2O3-Cr2O3 composite gradient hydrogen-resistant coating having the thickness of 0.1-20 microns. The coating is a double-layer structure comprising an alumina inner layer and a chrome oxide external layer. The hydrogen-resistant coating has a high bonding degree with the base and has hydrogen resistance improved by 100-120 times. The preparation method has simple processes and a low cost.

Description

technical field [0001] The invention relates to a composite gradient hydrogen barrier coating and a preparation method thereof, especially containing Al 2 o 3 and Cr 2 o 3 Composite gradient hydrogen barrier coating and its preparation method. Background technique [0002] The solar high-temperature vacuum heat collection tube is composed of a stainless steel central tube with a spectrally selective absorption coating on the outer wall and an outer glass sleeve. In order to ensure good heat insulation effect, the annular space between the two tubes is evacuated. When the high-temperature vacuum heat collector tube is working, the stainless steel tube is loaded with high-temperature heat-resistant heat-conducting oil to exchange heat with the external working machine. The working temperature is between 300 and 400 ° C. Due to the aging of the heat-conducting oil, free hydrogen will be decomposed during long-term work. . Hydrogen can easily pass through the stainless stee...

Claims

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Application Information

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IPC IPC(8): B32B15/04B32B15/18B32B9/04C23C4/16C23C4/08C23C8/10F24J2/48C23C4/073C23C4/134
CPCY02E10/40
Inventor 于庆河郝雷刘晓鹏蒋利军王笑静杜淼米菁
Owner GRIMAT ENG INST CO LTD
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