A method for preparing ultrafine yttrium oxide-doped tungsten composite powder by freeze-drying

Abstract

The invention provides a method of preparing tungsten-doped superfine yttrium oxide compound powder by freeze drying. The method comprises the following steps: dissolving ammonium metatungstate and ayttrium nitrate hexahydrate in deionized water or distilled water, and carrying out ultrasonic treatment to disperse and dissolve the mixture to prepare a solution; pouring the solution into a surfacevessel or other containers large in surface areas, putting the surface vessel or other containers in a refrigerator, and pre-freezing the same at 40 DEG C below zero and 10 DEG C below zero; openingrefrigeration and a vacuum meter of a freeze drier in advance, and after the temperature of the freeze drier is reduced to the freezing temperature of 58 DEG C below zero and 20 DEG C below zero and is stabilized, putting the pre-frozen surface vessel in the freezer dryer, and opening a vacuum pump to maintain the vacuum degree and carry out freeze drying; putting the freeze-dried compound powderin a tubular furnace, and calculating the compound powder in a nitrogen or an argon air flow to obtain WO3-Y2O3 compound oxide powder; and carrying out two-step reduction with pure hydrogen in the tubular furnace to obtain the tungsten-doped superfine yttrium oxide compound powder. The average grain size is about 10nm, the grain size distribution is extremely narrow, and a bimodal distribution phenomenon is avoided.

Description

technical field [0001] The present invention proposes a brand-new method—freeze-drying method to prepare superfine W-Y 2 o 3 The technology of composite powder belongs to the technical field of powder preparation engineering. Background technique [0002] Tungsten-based materials are widely used in information, energy, Metallurgy, aerospace, national defense and nuclear industry and other fields. Meanwhile, tungsten-based materials are also considered to be the most promising plasmonic facing materials (PFMs). However, the brittleness of tungsten-based materials has been a problem that limits its application in the field of nuclear fusion, including low-temperature brittleness, recrystallization brittleness, and neutron irradiation brittleness. [0003] Studies have shown that an effective way to improve the performance of tungsten-based alloys is to reduce the grain size of the alloy to ultra-fine size, even to nano-scale size. A large number of grain boundaries introd...

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Problems solved by technology

[0004] At present, the traditional mechanical alloying method, vacuum drying method, sol-gel method, wet chemical precipitation method, spray drying method and other methods for the preparation of ultrafine precursor powder have certain limitations, and grinding cannot guarantee the purity. Uniform doping cannot precisely control the size, shape, and distribution of grains; other preparation methods have uneven structures, large grains, and bimodal distribution. , a meniscus will be formed between the particles and in the holes in the particles, resulting in a strong pulling force, causing the particle skeleton to collapse and closely contact, resulting in soft and hard agglomeration of particles and uneven particle size dispersion

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