Hydrogen plasma deoxidation method of chromium powder

Abstract

The invention discloses a hydrogen plasma deoxidation method for chromium powder. The hydrogen plasma deoxidation method is characterized by comprising the following steps: selecting a metal chromium block and crushing the metal chromium block into chromium powder of -325 to -1340 mesh; carrying out hydrogen plasma deoxidation on the chromium powder, wherein the deoxidation is carried out in a stainless steel container with radio-frequency hydrogen plasma equipment, the radio-frequency hydrogen plasma equipment takes hydrogen gas as a working gas, and a slotted water-cooling copper furnace is arranged in the stainless steel container; firstly, manufacturing the chromium powder subjected to ball grinding into a plurality of chromium powder rod bodies, each of which having a diameter of 15-20mm and a length of 20-3mm, preparing a plurality of chromium powder rod bodies from chromium powder subjected to ball grinding by arc melting in the presence of argon gas at 0.02-0.05Mpa, and then connecting every two chromium powder rod bodies end to end and placing on the slotted water-cooling copper furnace; feeding gas through the radio-frequency hydrogen plasma equipment; manufacturing chromium rods in an once forming manner through a zone-melting method so as to finish deoxidation. The hydrogen plasma deoxidation method is used for carrying out chromium powder deoxidation by using the radio-frequency plasma equipment and is simple in process and low in cost, and the oxygen content of the product can accord with using requirements.

Description

technical field [0001] The invention relates to a process for producing low-oxygen chromium powder by using a hydrogen plasma method, more precisely a method for hydrogen plasma deoxidation of chromium powder. Background technique [0002] In addition to being used in high-temperature alloys, chromium powder is also used as cermets, wear-resistant and corrosion-resistant coating materials, evaporation materials in the electronics industry, and additives for preparing switch contact alloys with oxidation resistance. More importantly, it is an important raw material for mechanical alloying superalloys. [0003] At present, the main method for preparing chromium powder is electrolysis with aqueous solution of chromate, but the oxygen content of electrolytic chromium powder is generally very high (0.7-1.0%, weight percent, not specified below, all are weight percent), carbon content It is also not suitable for the above-mentioned purposes. In order to obtain the chromium powde...

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Problems solved by technology

This treatment method not only takes a long time, but also has small processing capacity and low efficiency, and is only suitable for processing chromium powder with large particles (particle size greater than 0.15mm). Severe sintering often occurs when processing fine powder chromium

[0006] Utilize high temperature and gas reductant to the research of electrolytic chromium powder deoxidation, there are following technical difficulties: (1) under high temperature, chromium powder is seriously sintered; (2) under high temperature, the surface of chromium powder particle melts (t m.p =1903°C), making it difficult for the gas reducing agent to penetrate into the chromium powder; (3) Part of the chromium powder is gasified at high temperature to form black ultra-fine powder, which is mixed in the product chromium powder, failing to achieve the purpose of deoxidation

[0007] In addition, because of the high ionization energy of hydrogen gas (13.6eV) and high enthalpy value, it is difficult for hydrogen plasma with high ionization degree to exist stably in a high-frequency oscillating circuit. In short, high-frequency induction plasma equipment cannot realize full hydrogen plasma. Can only achieve mixed plasma of argon and a small amount of hydrogen

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