| US 7,594,973 B2 | ||
| Titanium material less susceptible to discoloration and method for production thereof | ||
| Kazuhiro Takahashi, Hikari (Japan); Teruhiko Hayashi, Hikari (Japan); Michio Kaneko, Futtsu (Japan); Kiyonori Tokuno, Tokyo (Japan); Junichi Tamenari, Hikari (Japan); and Kinichi Kimura, Tokyo (Japan) | ||
| Assigned to Nippon Steel Corporation, Tokyo (Japan) | ||
| Appl. No. 10/343,168 PCT Filed Jul. 19, 2001, PCT No. PCT/JP01/06302 § 371(c)(1), (2), (4) Date Jan. 27, 2003, PCT Pub. No. WO02/10481, PCT Pub. Date Feb. 07, 2002. |
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| Claims priority of application No. 2000-229803 (JP), filed on Jul. 28, 2000. | ||
| Prior Publication US 2003/0178112 A1, Sep. 25, 2003 | ||
| Int. Cl. C22C 14/00 (2006.01) | ||
| U.S. Cl. 148—421 [148/669] | 2 Claims |
| 1. A method of manufacturing titanium material less susceptible to discoloration comprising annealing the titanium material
prior to dissolving the surface of the titanium material in an aqueous solution of hydrofluoric and nitric acids; and thereafter,
heating the titanium material at between 300 and 900° C. in a vacuum or an inert gas atmosphere after dissolving the surface
of the titanium material in the aqueous solution of hydrofluoric and nitric acids;
thereby providing the titanium material having an oxide film not more than 100 angstrom in thickness on the surface thereof
containing not more than 3 at % fluorine and not more than 20 at % carbon in said oxide film.
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