PROCEDURE FOR PRODUCTION OF HIGH PURITY TUNGSTEN FOR SPUTTERING TARGET Russian patent published in 2011 - IPC C22B34/36 C22B3/24 C22B9/20 

FIELD: metallurgy.

SUBSTANCE: procedure consists in refining solution of ammonia paratangstate with sulphate of ammonia from molybdenum impurity. Further, refining is carried out with ion exchange on anionite AM-n and with thermal decomposition of ammonia paratangstate at temperature 600-800°C till production of tungsten trioxide. Tungsten trioxide is refined with zone sublimation at temperature 900-950°C in a continuous flow of oxygen. Further, trioxide of tungsten is heterogeneous reduced with hydrogen at temperature 700-750°C till production of powder of tungsten. Powder is compressed to tungsten rod which is subjected to electronic vacuum zone re-crystallisation till production of tungsten crystal. Tungsten crystals are melt in electron vacuum in a flat crystalliser with melt of flat ingot of tungsten on each side at total depth not less, than twice. A tungsten rod is treated with chlorine prior to zone re-crystallisation at rate of chlorine supply 100 ml/min and temperature 300°C during 1 hour.

EFFECT: raised purity of tungsten designed for thin film metallisation by magnetron target sputtering and improved electro-physical parametres of applied thin layers.

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