Mixture Of Tungsten-cobalt Precipitation - To Restore The Study Of The Preparation Process

In this thesis, the history and development of WC-Co cemented carbide are briefly introduced. Then the conventional producing technology of WC-Co cemented carbide,Liquid chemical method and the latest development are reviewed, and the wear, fracture toughness and fatigue mechanism of the WC-Co cemented carbide are briefly discussed.WC-Co cemented carbides are widely used in drilling, mining, cutting tools, molds and other fields, because of its high wear resistance, high strength, high toughness, high hardness and high heat stability. However, the distribution of composite of WC and Co is not very even which is made by traditional methods of mechanical Mixture, which limits the application and development of tungsten carbide greatly, in this thesis we use an method which is called Liquid chemical method to make cobalt-phase distribute around the WC adequately, obtains a composition which is well-proportioned of WC and Co,and make out WC-Co cemented carbides which have a perfect performance.This thesis investigates the influence of deoxidization extent by changing the conditions of reactive solvent,molar ratio and reactive temperature in the preparation process of WC-Co Composite by liquid chemical method, the result shows that when the reaction happening at room temperature,using alcohol as reactive solvent and the value of molar ratio is 3:1, the oxygen content of cobalt is the lowest; And investigates the influence of these three factors affect on the distribution of particles of the cobalt compound by orthogonal experimental study, as well as the influence on the median diameter, the result shows that that when the reaction happening under the condition of using distilled water as reactive solvent,the value of molar ratio is 2:1, the distribution of cobalt precursor compounds is the narrowest, can receive a smallest diameter when using alcohol as reactive solvent and the value of molar ratio is 2:1; Investigates the influence on the distribution of cobalt phase by changing the condition of reactive solvent, the result shows that that the distribution of cobalt element in WC-Co Composite is the most uniform when using alcohol as reactive solvent.The thesis uses the variable search method to research the influence of WC-Co cemented carbide's mechanical physical properties by changing the conditions of reactive solvent,filling add triethanolamine,molar ratio,reactive temperature and the drops acceleration factor of ammonia systematically, combines with metallographic images,scanning electron microscope images and the test data of mechanical properties, uses MINITAB 14 to carry out analysis of the test data, finds out the three most important factors which can affect tungsten carbide's comprehensive performance deeply are:the drops acceleration factor of ammonia,the reactive solvent and the molar ratio, Uses the full-factor experiment to determine the optimum conditions of liquid chemical method to produce WC-Co tungsten carbide, namely, the rate of the drops acceleration factor of ammonia is 20ml/min,using distilled water as reactive solvent and molar ratio is 3:1, then deoxidizes the composite,suppresses the samples and sinters it to produce WC-Co cemented carbides which have a best overall performance.