Method for Improving Oxidation Resistance of Graphite Electrodes by Chemical Vapor Deposition SIC/C Gradient Surface Coating

A technology of chemical vapor deposition and graphite electrodes, which is applied in the direction of coating, gaseous chemical plating, metal material coating technology, etc., can solve the problems of decreased protection effect, improve oxidation resistance, enhance bonding degree, and reduce steel consumption per ton volume reduction effect

Inactive Publication Date: 2011-12-14
NANJING UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Using this method can realize the anti-oxidation protection of graphite electrodes in the lower temperature range, but in the high temperature range, especially at 1000 o Above C or ev

Method used

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  • Method for Improving Oxidation Resistance of Graphite Electrodes by Chemical Vapor Deposition SIC/C Gradient Surface Coating
  • Method for Improving Oxidation Resistance of Graphite Electrodes by Chemical Vapor Deposition SIC/C Gradient Surface Coating

Examples

Experimental program
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Example Embodiment

[0023] Example 1

[0024] The ultra-high power graphite electrode with a diameter of 450mm and a length of 1500mm is selected as the substrate, and the graphite electrode is processed according to the following process:

[0025] Step 1. Perform surface cleaning, polishing, cleaning and drying on the graphite electrode.

[0026] Step 2: Fix the graphite electrode after surface pretreatment on the support in the water-cooled reaction furnace of the chemical vapor deposition equipment, and evacuate the furnace to 0.2Pa.

[0027] Step 3. Heat the graphite electrode in the reaction furnace, and when the temperature reaches 1400℃, pass CH 4 The gas pressure in the reactor is maintained at 1kPa and maintained for 2h under this condition to form a layer of pyrolytic carbon on the surface of the graphite electrode.

[0028] Step 4. Infuse carrier gas H 2 , H 2 Via boiling SiCl 4 Liquid, SiCl 4 Bring out and with CH 4 The gas is reactively deposited on the surface of the graphite electrode. The r...

Example Embodiment

[0031] Example 2

[0032] The ultra-high power graphite electrode with a diameter of 450mm and a length of 1500mm is selected as the substrate, and the graphite electrode is processed according to the following process:

[0033] Step 1. Perform surface cleaning, polishing, cleaning and drying on the graphite electrode.

[0034] Step 2: Fix the graphite electrode after surface pretreatment on the support in the water-cooled reaction furnace of the chemical vapor deposition equipment, and evacuate the furnace to 0.5 Pa.

[0035] Step 3. Heat the graphite electrode in the reaction furnace. When the temperature reaches 1450℃, pass CH 4 The gas is used to maintain the pressure in the reactor at 1.5kPa and maintain it for 3h under this condition to form a layer of pyrolytic carbon on the surface of the graphite electrode.

[0036] Step 4. Infuse carrier gas H 2 , H 2 Via boiling SiCl 4 Liquid, SiCl 4 Bring out and with CH 4 The gas is reactively deposited on the surface of the graphite elect...

Example Embodiment

[0039] Example 3

[0040] The ultra-high power graphite electrode with a diameter of 450mm and a length of 1500mm is selected as the substrate, and the graphite electrode is processed according to the following process:

[0041] Step 1. Perform surface cleaning, polishing, cleaning and drying on the graphite electrode.

[0042] Step 2: Fix the graphite electrode after surface pretreatment on the support in the water-cooled reaction furnace of the chemical vapor deposition equipment, and evacuate the furnace to 0.8 Pa.

[0043] Step 3. Heat the graphite electrode in the reaction furnace. When the temperature reaches 1500℃, pass CH 4 The air pressure in the reactor is maintained at 2kPa and maintained for 1h under this condition to form a layer of pyrolytic carbon on the surface of the graphite electrode.

[0044] Step 4. Infuse carrier gas H 2 , H 2 Via boiling SiCl 4 Liquid, SiCl 4 Bring out and with CH 4 The gas is reactively deposited on the surface of the graphite electrode. The rea...

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Abstract

The invention discloses a method for improving the oxidation resistance of a graphite electrode by obtaining a SiC/C gradient surface coating through chemical vapor deposition. The method comprises the following steps of: performing surface pretreatment on the graphite electrode; fixing the graphite electrode which is subjected to surface pretreatment on a support in a water-cooled reaction furnace of chemical vapor deposition equipment, and vacuumizing in the furnace; heating the graphite electrode in the reaction furnace, and aerating CH4 gas to form a layer of pyrolytic carbon on the surface of the graphite electrode; keeping the temperature of a cavity unchanged, aerating carrier gas H2 to pass through boiling SiCl4 liquid, and reacting SiCl4 gas carried by the carrier gas H2 and the CH4 gas on the surface of the graphite electrode and depositing; and after the deposition is finished, keeping the temperature of the cavity unchanged, maintaining H2 atmosphere, performing in-situ heat treatment on the graphite electrode in the furnace, and cooling the graphite electrode to room temperature in the furnace after the heat treatment is finished so as to obtain the graphite electrodewith a SiC/C gradient functional surface protective layer. The invention has the advantages that: the permeability is high, the coating can permeate into any fine pores on the surface of a matrix of the graphite electrode, and a good effect of resisting the oxidation of surface voids can be achieved.

Description

technical field [0001] The invention belongs to graphite electrode surface treatment and surface modification technology, in particular to a method for improving the oxidation resistance of graphite electrode by chemical vapor deposition SiC / C gradient surface coating. Background technique [0002] Heavy-duty electrodes cause the electrodes to fall off and fall off. Graphite electrodes are indispensable conductive consumables for electric arc furnaces and play an important role in electric furnace smelting technology. Graphite electrodes used by metallurgical enterprises have the characteristics of good high temperature performance, low thermal expansion coefficient, light weight, and easy processing. However, in the high temperature and oxygen blowing environment of iron and steel smelting, graphite electrodes are prone to oxidation reactions with oxygen, resulting in consumption. The cost brought by the consumption of graphite electrodes accounts for about 1 / 3 of the tot...

Claims

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Application Information

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IPC IPC(8): C23C16/26C23C16/32H05B7/085C04B41/89
Inventor 徐锋廖志钦杨晓智刘明
Owner NANJING UNIV OF SCI & TECH
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