What is the production method of chromium carbide?
Release time:
2022-07-25 09:41
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What is the production method of chromium carbide?
Chromium carbide is gray powder with metallic luster; orthorhombic system; density is 6.68g/cm3; melting point is 1890, boiling point is 3800. It has good wear resistance, corrosion resistance and oxidation resistance at high temperature (1000~1100). Belongs to metal ceramic. So, what is the production method of chromium carbide?
What is the production method of chromium carbide?
1. The method of carbonization of metal powder is to crush carbon black and electrolytic chromium with more than 1133 percent of theoretical carbon into 325 mesh metal chromium powder, which is dry mixed with a ball mill as raw material.
2. 1% ~ 3% stearic acid is added as molding lubricant, and the pressure is greater than 1 T/cm2. Put the pressed powder into a graphite plate or crucible, heat it to 1500~1700 in a hydrogen stream (hydrogen dew point is about -35) with a Taman furnace or an induction heating furnace, and keep it for 1 hour to carbonize chromium to generate chromium carbide, and then cool to obtain chromium carbide.
What are the characteristics of chromium carbide?
1. The oxidation resistance of metal carbides is strong, and it starts to oxidize obviously only when 1100-1400 degrees in the air. It still maintains a fairly high hardness at high temperatures. Cr3c2 also has strong corrosion resistance and wear resistance. In dilute sulfuric acid solution, the corrosion resistance of 1 Cr 18 ni 9 ti stainless steel is 30 times that of co-wc alloy, and in steam, its corrosion resistance is 50 times that of co-WC alloy. When the nicr-cr3c2 is sprayed on the boiler tube of the power plant, the wear of the tube wall is reduced from 1.5-2.0mm/year to 0.03mm/year, and the service life is extended to more than seven years. Usually nicr is used as the binder phase of heat-resistant alloy, and the coating is formed by thermal spraying, which is close to the hardness of cr3c2, so as to form an excellent high temperature and wear-resistant material. The use of hvof or plasma spraying technology can make nicr alloy and cr3c2 ceramics have sufficient conditions to form a uniform cermet coating, which has the functions of anti-wear, anti-erosion, anti-cavitation and high-temperature micro-vibration, and also has the ability to resist high-temperature gas (even gas containing S) corrosion and high-temperature oxidation. Typical applications include: coal-fired boiler tubes (power plants, paper mills), metallurgical annealing furnace rollers, thermoforming molds, hydraulic machine valves, combustion rod mandrels, turbine gas sealing rings, air gates, inner nozzle supports, pump sleeves, hot crushing rollers, piston guides, shift forks, compressor gas seals, expansion joints, turbine nozzles, fake tools, turbine exhaust supports, etc.
2. The melting point of chromium carbide is low, 1710 degrees Celsius, and the density is 6.68 gcm-3. Its main features are high room temperature hardness and hot hardness, good wettability with Co, Ni and other metals, and high oxidation resistance in metal carbides. It only suffers severe oxidation at temperatures of 1100 degrees Celsius to 1400 degrees Celsius in the air, and has excellent corrosion resistance. It is a kind of high temperature oxidation resistance, anti-friction wear and anti-gas corrosion material with excellent comprehensive performance. Mainly used for high temperature resistant coating, but direct spraying chromium carbide coating adhesion is not strong. Therefore, it is mainly used as a main raw material component for preparing the NiCr-Cr3C2 composite powder.
Chromium carbide
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