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Preparation method for nano chrome carbide composite powder

A technology of nano-chromium carbide and composite powder is applied in the field of preparation of nano-chromium carbide composite powder, which can solve the problems of difficulty in obtaining nano-scale chromium carbide particles, and achieve the effect of avoiding the growth of nano-grains

Active Publication Date: 2011-08-17
BEIJING GENERAL RES INST OF MINING & METALLURGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to solve the problem that it is difficult to obtain nano-scale chromium carbide particles in the existing methods, the present invention provides a preparation method of nano-chromium carbide composite powder

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Select nickel-chromium alloy powder, the particle size of the nickel-chromium alloy powder is below 75 μm, then ball mill the nickel-chromium alloy powder for more than 30 minutes, put the ball-milled powder in an atmosphere furnace, and feed hydrogen and A mixture of carbon gas, the furnace temperature is kept between 650 and 950°C, and the chromium carbide composite powder is obtained after heat preservation, and the obtained powder is crushed and classified to obtain the finished powder. The weight ratio of chromium in the nickel-chromium alloy powder is 70-80%. The particle size of the nickel-chromium alloy powder is 20-45 μm. The flow ratio of the carbon-containing gas to the hydrogen is 1:1.2-5. The carbon-containing gas is acetylene, methane, propane, carbon monoxide or petroleum cracking gas. The heat preservation time is 1 to 3 hours.

Embodiment 2

[0016] Select 1 kg of NiCr alloy powder with a particle size of less than 45 μm and 70% chromium, put it in a graphite pan after ball milling for 30 minutes, place it in an atmosphere furnace (the furnace diameter is 150 mm) and heat it to 950 ° C, then pass it into acetylene and The mixed gas of hydrogen (the flow ratio of acetylene and hydrogen is 1: 4.5), the flow rate of hydrogen is 150ml / min, after being kept warm for 1 hour, it is cooled, and the powder is crushed to obtain nickel-chromium-chromium carbide composite powder containing about 70wt% of chromium carbide , the grain size of chromium carbide is between 30 and 80 nanometers.

Embodiment 3

[0018] Select 1 kg of NiCr alloy powder with a particle size below 45 μm and 80% chromium content, put it in a graphite pan after ball milling for 60 minutes, place it in an atmosphere furnace (the furnace diameter is 150 mm) and heat it to 650 ° C, then pass it into acetylene and The mixed gas of hydrogen (the flow ratio of acetylene and hydrogen is 1: 1.2), the flow rate of hydrogen is 200ml / min, after 3 hours of heat preservation, cooling, the powder is crushed, and the nickel-chromium-chromium carbide composite powder containing about 75wt% of chromium carbide is obtained , the grain size of chromium carbide is between 30 and 80 nanometers.

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Abstract

The invention relates to a preparation method for nano chrome carbide composite powder. The method comprises the following steps of: performing ball-milling on nickel-chrome alloy powder, and putting into an atmosphere furnace; introducing mixed gas which comprises hydrogen and carbon-containing gas, wherein the temperature of the atmosphere furnace is kept between 650 and 950 DEG C; and crushing and classifying chrome carbide composite powder which is obtained after heat preservation. In the method, a nickel-chrome alloy is used as a raw material, and a large number of dislocation defects are formed inside metal powder in the ball milling process, so that carbon atoms are dispersed in the dislocation of alloy metals in the subsequent process, the powder obtained after the ball-milling is carbonated under the carbon-containing atmosphere, and a nano chrome carbide hard phase is generated in situ in the nickel-chrome alloy by controlling the concentration of the carbon-containing atmosphere and the heating temperature. By the method, the problem of nano grain growth in the composite powder sintering process is solved.

Description

technical field [0001] The invention relates to a preparation method of nano-chromium carbide composite powder, belonging to the technical field of preparation of chromium carbide composite powder. Background technique [0002] Chromium carbide cermet is a widely used cermet powder. Chromium carbide has a series of advantages: ①Good oxidation resistance; ②High hardness at high temperature; ③Excellent wear resistance; ④Expansion coefficient is higher than other cermet materials It is close to steel; ⑤ high corrosion resistance, and has excellent corrosion resistance in various corrosive media; ⑥ low density, only about half of tungsten carbide cermets. [0003] In the thermal spraying industry, chromium carbide is often used to prepare composite powder, and the composite powder formed from chromium carbide powder and NiCr alloy is often used as a wear-resistant protective coating in a high-temperature friction environment of 600-850 °C. Currently Cr 3 C 2 The preparation m...

Claims

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Application Information

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IPC IPC(8): C22C1/04C22C29/06C01B31/30
Inventor 高峰沈婕张乐赵晓东侯伟骜万伟伟国俊丰
Owner BEIJING GENERAL RES INST OF MINING & METALLURGY