PRODUCTION OF HIGH-PURITY WIRE ROD OR SHEET PLATE

• Main Authors: DEGAWA TORU, KOIWA MASAHIRO, YOSHINARI OSAMU
• Format: Patent
• Language: English
• Published: 22.06.1988
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

PURPOSE:To efficiently performing deoxidation and denitrification treatment and to obtain a high-purity wire rod or sheet plate excellent in workability or the like by plating the coating film of active elements in a vapor phase on the surface of the wire rod or the sheet plate made of metal or alloy, thereafter heating it in the nonoxidative atmosphere. CONSTITUTION:The coating film 3 of active elements such as alkaline earth elements like Ca and Ba, etc., and rare earth elements are formed on the surface of the wire rod 1 or the sheet plate 2 made of metal or alloy by means of a vapor-phase plating method such as a PVD method and a CVD method. As the above-mentioned metal or alloy, for example transition metal such as Cr, V, Fe and Co or alloy contg. these metals as a main element is used. Further the thickness of the coating film 3 is prefer ably regulated to about 1-100mum. Then the wire rod 1 or the sheet plate 2 formed with the coating film 3 is heated in the nonoxidative atmosphere such as the inactive atmosphere of Ar or the like. Thereby oxygen and nitrogen incorporated in the base material of the wire rod 1 or the sheet plate 2 are diffused into the coating film 3 of active metals and both deoxidation and denitrification can be performed. In this case, the diffusing treatment is generally performed at heating temp. of 800-1,200 deg.C. Further the low-oxygen and low-nitrogen wire rod and sheet plate are shown by 11 and 12 in a figure respectively.