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Preparation and properties of W - 10Cu composites

Author: YouFeng
Tutor: FanJingLian
School: Central South University
Course: Powder Materials Science and Engineering
Keywords: Spray-dried Ultra - fine tungsten powder Infiltration Particle size ratio W - 10Cu composite
CLC: TB331
Type: Master's thesis
Year: 2009
Downloads: 47
Quote: 0
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Abstract


W-Cu composite material with high thermal conductivity properties, good corrosion resistance arc welding resistance and high strength, etc., are widely used in high-voltage switch contact material, especially vacuum switch electrical contact material. However, the preparation of tungsten-copper composite the ubiquitous material density, low strength, low conductivity of issues that hinder the application of tungsten-copper composite materials in electrical switches. In order to solve these problems, the present study as a raw material through to ultra-fine tungsten powder and the type of particle diameter ratio of tungsten powder, the design skeleton sintering and melt infiltration process, preparation of a composite material of high performance W-10Cu. This thesis ultra-fine tungsten powder Preparation, Preparation and Properties of W-10Cu composites. In order to further improve the density of the material, the paper also studied the impact of different particle size of the tungsten powder ratio on the material properties. The study results showed that: (1) Ammonium metatungstate (AMT) by the spray-dried powder particles having a spherical shell-like structure. This powder calcined at 450 ℃ and then step hydrogen reduction at 750 ℃, the particle size of 0.4, the average grain size of only 33nm ultra-fine tungsten powder. (2) In the ultrafine tungsten powder as raw materials, preparing a relative density of 80.26% tungsten skeleton. The skeleton infiltrated at 1300 ℃ 120min density 16.79g/cm3 (97.14%) relative density, hardness 31HRC conductivity of 39.7% IACS W-10Cu composite was prepared. (3) the shrinkage of the skeleton with the sintering temperature increases. High-temperature sintering the skeleton to produce a certain shrinkage, so that the porosity to meet the requirements of 10 wt% of copper infiltration. The density of the material with the melt infiltration time increases. Hardness and conductivity with infiltration time increases first and then decreased. Preparation of W-10Cu composites reasonable process: infiltration temperature of 1300 ° C, infiltration time 120min. (4) two kinds of particle diameter ratio of tungsten powder and W-10Cu composite materials, the density, hardness and electrical conductivity of the material also increases with the increase of the particle diameter ratio. Three kinds of particle diameter ratio of the tungsten powder and the density of the material, the hardness value but decreased with the increase of the particle diameter ratio, the conductivity increases with increasing particle diameter ratio. Law of variation of four particle size ratio of tungsten powder and W-10Cu composites with three particle size ratio prepared changes in material properties. Particle diameter ratio of 3:1 ratio of powder compacts sintered at 1350 ℃, holding time 90 min, tungsten skeleton relative density of 80.5%. Skeleton in the the 1300 ℃ infiltrated 120min after the relative density of the the w-10CU composite material reaches 98.9%, the Rockwell hardness of 28.9HRC 41.03% IACS conductivity.

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CLC: > Industrial Technology > General industrial technology > Materials science and engineering > Composite materials > Metal composite materials
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