By chemical vapor deposition direct production of dense tungsten products are of three types:

(1) Surface Coating: the part or parts of tungsten thin layer deposited on the surface, from corrosion or some functional role;

(2) Composite Material: the development of new materials with excellent mechanical properties;

(3) Shaped Products: a tubular, disc crucible complex shaped products;

Production of chemical vapor deposition of tungsten products, there are three types of methods: (1) thermal decomposition method (2) reduction of hydrogen halide (3) chemical vapor transport "water cycle" method

Difficulty from the production, operation Traditional and Simplified, toxicity, and low cost, quality and other advantages and disadvantages to consider, the current into the main method of industrial production stage hydrogen halide reduction method only. Which is the most widely chloride Hydrogen Reduction of tungsten coatings and composite materials and fluoride Hydrogen Reduction of shaped dense metal products.

O. M. Korolev (Kopojeb) for heating the outer surface of copper deposition process in the airflow rate by diffusion of reactants. With increasing content of WF6, diffusion controlling the kinetically controlled transition. 873K (about 2.4mm / h) and 973K (about 4.6mm / h), respectively, the maximum deposition rate of the WF6 concentration of 30% and 40% is reached.

Preparation of chemical vapor deposition of tungsten products does not require milling and forming stage, the deposition process is not only forming process, but also from the purification effect, can be obtained very high purity, density can reach theoretical density tungsten and tungsten coating products, so this France to get more and more widely used.

The early 1980s, the U.S. super-metal (Ultramet) Company uses fluoride hydrogen reduction of tungsten chemical vapor deposition method for the construction of a large fusion reactor fuel containers seamless tungsten crucible. Its diameter is 330mm, height 553mm, wall thickness of 1.52-2.03mm. Chemical vapor deposition is currently possible to manufacture such a large dense parts of the unique way.


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