TECHNOLOGY OF CHEMICAL TREATMENT OF ARTICLES MADE OF TITANIUM OR ITS ALLOYS Russian patent published in 2003 - IPC

FIELD: treatment of articles made of titanium or its alloys intended for use in instrumentation engineering, aircraft industry, mechanical engineering, medicine. SUBSTANCE: in process of chemical treatment of articles made of titanium or its alloys they are degreased, washed, dried and each treated twice, as minimum, in the course of 1-3 min in solution containing following proportion of components, g/l: nitric acid, 426-497; sulfuric acid, 552-644; hydrofluoric acid, 171-228; sulphaminic acid, 50-60; pyrazolone compound 2-15. Article is washed in water and dried before each treatment, after final treatment article is washed in running water for 2-3 min, washed in water again for 2-3 min at temperature of 60-80 C and dried. Articles made with the aid of welding or having welds of high- temperature seal are treated in above-mentioned solution at temperature of 30-40 C in the course of 2-5 min. Quantity of pyrazolone compound in this case amounts to 3-8 g/l. Articles produced by electric erosion methods are treated in above-mention solution at temperature of 18-25 C in the course of 20-60 min. Solution for this case additionally contains salt of titanium in the amount of 5 to 15 g/l in terms of metal and quantity of pyrazolone compound in solution is 2-5 g/l. Technology provides for high degree of purity of surface and high degree of decoration of complex profile articles, increases corrosion resistance of polished surface to attacks of climatic factors and biologically active media and secures high-quality precision preparation of surfaces of articles having brazed seams or carbide layer after electric erosion treatment. EFFECT: high degree of purity of surfaces of articles made of titanium of its alloys. 5 cl, 2 tbl