Method for preparing rare-earth oxide dispersion strengthened fine-grained tungsten material

Abstract

A method for preparing a rare-earth oxide dispersion strengthened fine-grained tungsten material, comprising: according to a condition that a mass percentage of rare-earth oxide is 0.1-2%, and the remaining composition is W, weighing soluble rare-earth salt and tungstic acid salt, and respectively preparing 50-100 g / L of rare-earth saline solution and 150-300 g / L of tungstic acid saline solution; adding a minor amount of alkali into the rare-earth salt to control the pH to be 7-8, adding an organic dispersing agent, and stirring to enable the rare-earth salt to form uniformly suspending R(OH)3 colloidal particles (R represents a rare-earth element); adding the tungstic acid saline solution into the R(OH)3 colloidal particles, adding a minor amount of acid to control the pH to be 6-7, adding the organic dispersing agent, stirring to enable the tungstic acid salt to form tungstic acid micro-particles, precipitating and coating the R(OH)3 colloidal particles with the R(OH)3 colloidal particles as a core, and forming coprecipitated coated colloidal particles; conducting spray drying on the coprecipitated coated colloidal particles to obtain a composite precursor powder of tungsten and rare-earth oxide; calcining, conducting thermal reduction via hydrogen, and preparing superfine nanometer tungsten powder having a particle size of 50-500 nm; and conducting normal high-temperature sintering after a general pressing forming. The high-performance fine-grained tungsten material dispersed and strengthened by a minor amount of rare-earth oxide prepared by the above method has a density approximate to full density (>=98.5%), and uniform and small tungsten grains having an average size of 5-10 [mu]m; in addition, rare-earth oxide particles having a particle size of 100 nm - 500 nm are uniformly distributed in a tungsten crystal or a crystal boundary.

Description

Technical field: [0001] The invention relates to the fields of nanomaterials and powder metallurgy, in particular to a method for preparing rare earth oxide dispersion-strengthened fine-grained tungsten materials prepared by nanocomposite technology. Background technique: [0002] Tungsten has high melting point, high hardness, good high temperature strength, thermal conductivity, electrical conductivity, low thermal expansion coefficient, low sputtering when interacting with plasma, no chemical reaction with H, H + With low retention characteristics, it is a very important high-temperature structural material and functional material, and is widely used as a plasma-facing material and divertor component material in the field of nuclear fusion. [0003] Among the tungsten materials that have been applied, pure tungsten materials are typical high-temperature materials that are widely used at present. At present, sintered pure tungsten materials are prepared by means of high p...

AI Technical Summary

Problems solved by technology

However, there are some problems in the above-mentioned preparation method: powders prepared by high-energy ball milling or mechanical alloying are prone to uneven distribution of components and introduction of heterogeneous impurities, while SPS and hot pressing sintering methods are not suitable for large-scale preparation of engineering

However, due to the poor compatibility between tungsten and the surface of rare earth oxide particles, tungsten materials containing trace rare earth oxides are directly prepared by sol-spray drying method, and the dispersion strengthening effect of rare earth oxide particles on tungsten is very limited, resulting in poor performance of the material , it is difficult to meet the requirements for the use of nuclear fusion tungsten materials