A kind of preparation method of composite tungsten electrode material

Abstract

The invention discloses a preparing method of a compound tungsten electrode material. The preparing method comprises the following steps of selection of oxides, prereduction, hydrogen gas reduction, high-energy mixing, forming and middle-frequency induction sintering. According to the preparing method of the compound tungsten electrode material, single-crystal ammonium paratungstate is subjected to clearance-type reduction to prepare blue tungsten oxide with a specific phase component, blue tungsten oxide is reduced to generate like-spherical tungsten powder, and the tungsten powder and one ormore of submicron-order oxides of cerium oxide, lanthanum oxide, yttrium oxide, zirconium oxide and the like are efficiently mixed in a high-energy powder mixing machine of a specific structure and subjected to isostatic compaction and low-temperature long-time middle-frequency induction solid-phase sintering; second-phase grains of obtained tungsten bars are fine and uniform, and the tungsten bars are free of segregation, high in rare earth retention rate and good in processing performance; the finished product rate reaches 87% or above, and the processing cost is reduced by 20% or above. Anexisting conventional technology is adopted for the tungsten bars for press working and machining, the finished product rate is high, and the compound tungsten electrode material which is low in arcing voltage, good in arc stability, low in burn-out rate, long in service life and environmentally friendly is obtained.

Description

technical field [0001] The invention relates to tungsten metallurgy technology, in particular to a preparation method of a composite tungsten electrode material. Background technique [0002] Tungsten has the characteristics of high melting point, good high temperature strength, strong thermal electron emission ability, etc., adding cerium oxide (CeO) with low electron work function and high melting point 2 ), lanthanum oxide (La 2 o 3 ), yttrium oxide (Y 2 o 3 ), zirconia (ZrO 2 ) of tungsten-based materials are best used in thermionic emission materials. Widely used in inert gas shielded welding, plasma welding, cutting, thermal spraying and electric vacuum and other fields. Its emergence and development have led to the development of welding technology. The construction of large structural parts such as skyscrapers, long-span bridges, pressure pipeline containers, and ships cannot do without argon arc welding technology. There are not only requirements for reliabil...

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Problems solved by technology

[0003] As we all know, the composite tungsten electrode material prepared by the traditional method of powder metallurgy is to add nitrate to the oxide of tungsten. Among them, the best reaction in the market is the tungsten thorium electrode material, which has a lower electron work function and high However, the thorium oxide in the tungsten material has serious radioactivity, causing serious harm to the human body; secondly, tungsten-cerium electrode material is widely used in the market, and its preparation method is a method disclosed in Chinese patent application CN85100184A. The method is in WO 3 The cerium tungsten electrode material is prepared by adding cerium nitrate solution to the cerium tungsten electrode material. Although this method avoids the hazards of radioactivity, the size and uniformity of the rare earth particles of the cerium tungsten electrode material produced are also very considerable, but it is difficult to eliminate NO 2 In addition, in the process of preparing tungsten powder by reducing tungsten oxide mixed with rare earth nitrate, a large amount of acid gas will be generated when the nitrate is converted into rare earth oxide, which will corrode the hydrogen pipeline of the reduction equipment. Seriously, acidic gas will also cause harm to the human body, which is not conducive to industrial production; there are also some companies that use solid-solid mixing. This method can certainly eliminate environmental pollution, but this method cannot eliminate aggregates in the powder, rare earth oxidation The degree of dispersion of the compound in the matrix is ​​not good, and the distribution of rare earth particles is extremely uneven after mixing. The prepared rare earth tungsten-based functional materials are relatively poor in burning loss and arc starting performance, which cannot meet their performance; the other is a Chinese patent. The suspension crystallization method disclosed in the application CN1042675A produces rare earth tungsten-based functional materials. The rare earth particles of the electrode material produced by this method are evenly distributed, and it also solves the problem of NO 2 pollution problem, but its production process needs to go through 8 processes from batching, evaporation crystallization to sintering, and the evaporation crystallization process is complicated and the production efficiency is extremely low, which is not conducive to modern and efficient production mode