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Method for preparing nano aluminum oxide coated tungsten powder

A technology of nano-alumina and coating tungsten powder, which is applied to the preparation of composite powder coated with nano-alumina on the surface of tungsten powder, and the field of preparation of nano-alumina-coated tungsten powder, which can solve the problem of expensive raw materials and coating powder. Agglomeration, harsh preparation conditions and other problems, to achieve the effect of preventing single-phase particle segregation, cheap and easy to obtain raw materials, and simple operation

Inactive Publication Date: 2009-11-04
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] (1) The particle size of the alumina-coated tungsten powder obtained by ball milling is uneven, and the alumina of the coating layer cannot reach the nanometer level, and the coated powder is easily polluted;
[0004] (2) The raw materials used in the liquid phase method are expensive, the preparation conditions are harsh, and it is difficult to control, and the final coating powder has agglomeration due to the existence of the liquid phase
[0005] The existence of these problems limits the development and application of nano-alumina-coated tungsten powder composites

Method used

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  • Method for preparing nano aluminum oxide coated tungsten powder
  • Method for preparing nano aluminum oxide coated tungsten powder
  • Method for preparing nano aluminum oxide coated tungsten powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) According to the final molar ratio of alumina and tungsten powder is 2: 8, weigh 3.567 grams of ammonium metatungstate white crystal powder and 2.222 grams of aluminum sulfate white crystal powder respectively, dissolve the two in 250 milliliters of distilled water, wait clarify;

[0023] (2) Use a nitrogen spray gun to disperse the clarified mixed solution in liquid nitrogen to obtain a frozen substance, and the spray gun pressure is 1.5 atmospheres;

[0024] (3) Place the frozen material in a freeze dryer for vacuum drying. The execution procedure of the freeze dryer is as follows: the working pressure is 250 millitorr and the temperature is -24°C within 0 to 2400 minutes; The working pressure is 150 millitorr and the temperature is -14°C; the working pressure is 80 millitorr and the temperature is -1°C within 3800 to 4600 minutes; the working pressure is 0 millitorr and the temperature is 4600 to 4800 minutes 20°C;

[0025] (4) Put the freeze-dried mixed powder...

Embodiment 2

[0027] (1) According to the final molar ratio of alumina and tungsten powder is 2: 8, weigh 4.28 grams of ammonium metatungstate white crystal powder and 2.666 grams of aluminum sulfate white crystal powder respectively, dissolve the two in 300 milliliters of distilled water, wait clarify;

[0028] (2) Use a nitrogen spray gun to disperse the clarified mixed solution in liquid nitrogen to obtain a frozen substance, and the spray gun pressure is 2 atmospheres;

[0029] (3) Place the frozen material in a freeze dryer for vacuum drying. The execution procedure of the freeze dryer is as follows: the working pressure is 300 millitorr and the temperature is -26°C within 0 to 2400 minutes; The working pressure is 160 millitorr and the temperature is -13°C; the working pressure is 50 millitorr and the temperature is 0°C within 3800 to 4600 minutes; the working pressure is 0 millitorr and the temperature is 25 within 4600 to 4800 minutes ℃;

[0030] (4) Put the freeze-dried mixed pow...

Embodiment 3

[0033] (1) According to the molar ratio of final alumina and tungsten powder is 2: 8, weigh 5.35 grams of ammonium metatungstate white crystal powder and 3.332 grams of aluminum sulfate white crystal powder respectively, dissolve the two in 400 milliliters of distilled water, wait clarify;

[0034] (2) Use a nitrogen spray gun to disperse the clarified mixed solution in liquid nitrogen to obtain a frozen substance, and the spray gun pressure is 2.5 atmospheres;

[0035] (3) Place the frozen material in a freeze dryer for vacuum drying. The execution procedure of the freeze dryer is as follows: the working pressure is 350 millitorr and the temperature is -28°C within 0 to 2400 minutes; The working pressure is 180 millitorr and the temperature is -15°C; the working pressure is 100 millitorr and the temperature is -3°C within 3800 to 4600 minutes; the working pressure is 20 millitorr and the temperature is 4600 to 4800 minutes 15°C;

[0036] (4) Put the freeze-dried mixed powde...

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Abstract

The invention relates to a method for preparing nano aluminum oxide coated tungsten powder, belonging to the field of powder metallurgical preparation. The method solves the problems of being uneven in particle size, not reaching nanoscale, being easy to pollute, agglomeration of powder and the like in the current preparation of the nano aluminum oxide coated tungsten powder. The coated power is characterized in that nano aluminum oxide is coated on the surface of micron-sized tungsten powder, and the mol content of the aluminum oxide is 10-30%. The method for preparing the coated powder is characterized in that ammonium metatungstate powder and aluminium sulphate powder are dissolved in distilled water together, and then dispersed in liquid nitrogen for pre-freezing by using a nitrogen spray gun after being clarified; the pre-frozen mixture is placed into a freeze-dryer for vacuum drying, so that freeze-dried powder can be obtained; under hydrogen atmosphere, the freeze-dried powder is calcined and deacidized in a sectional form, and composite powder of the nano aluminum oxide coated tungsten powder can be obtained. The invention has the advantages of fewer steps in the preparation process, simple operation, cheap and easily obtained raw materials and needing not to add matrix phase particles in advance.

Description

Technical field: [0001] The invention relates to a preparation method of nano-alumina-coated tungsten powder, in particular to a preparation method of a composite powder in which nano-alumina is coated on the surface of tungsten powder, and belongs to the field of powder metallurgy preparation of coated powder. Background technique: [0002] The composite material prepared by the composite powder obtained by uniformly doping metal-based particles with nano-ceramic powder not only has the excellent toughness and thermal conductivity of metal, but also has the high temperature resistance, wear resistance and corrosion resistance of ceramics, as well as high hardness and high Chemical stability and other characteristics have attracted extensive attention. In order to ensure the dispersion uniformity of the composite particles and maximize the performance of the material, it is often required to coat the dopant phase particles on the surface of the matrix particles to form a coa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/02
Inventor 聂祚仁席晓丽徐祥阳左铁镛
Owner BEIJING UNIV OF TECH
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