| 摘要 |
1,226,833. Pyrolytic carbon. GULF GENERAL ATOMIC Inc. 26 June, 1968 [29 June, 1967], No. 30426/68. Heading C1A. [Also in Divisions A5 and C7] ' Substrate materials which are stable at temperatures of at least about 1000‹ C. are coated with a layer of pyrolitic carbon having a density of at least about 1.5 grams per c.c. and an apparent crystallite size (as defined) no greater than about 200 A. The substrates are shaped to serve as surgical or medical prosthetic devices, e.g. pins or tubes (see Division A5). Suitable substrate materials include artificial graphite, boron carbide, silicon carbide, tantalum, molybdenum, tungsten, and ceramics such as mullite. Coating of the substrate is suitably effected by pyrolysing a hydrocarbon, such as methane, propane or butane, at high temperatures and depositing the carbon formed on the substrate. Coating can be effected using a rotating drum coater or a vibrating table coater. Where the substrate article is small enough to be levitated in an upwardly flowing gas stream, a fluidized bed coater is preferably used. The pyrolytic carbon product may be treated with a solution of heparin e.g. in saline, to reduce its coagulative action, and sterilized e.g. by heating in an atmosphere of ethylene oxide. |
