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SwRI offers diamond-like carbon coating process for biomedical applications
Process makes costs comparable to physical vapor deposition
San Antonio, Texas -- September 3, 1996 -- Scientists at Southwest Research Institute® (SwRI®) in San Antonio, Texas, have successfully demonstrated a diamond-like carbon (DLC) coating process at a cost comparable to physical vapor deposition, making the DLC process more attractive for specialized applications such as biomedical devices. First developed in the early 1980's at AEA Harwell in Britain, the DLC is produced using an ion beam-assisted process that deposits the coating at low temperatures.
Diamond-like carbon films have many of the same properties of diamond films -- low friction, high hardness, chemical inertness -- but are less expensive. In instances where biomedical applications involve friction and wear, such as is the case with artificial hip joints, diamond-like carbon is considered superior to polycrystalline diamond because exceptionally smooth coatings can be deposited. The DLC coatings offered by SwRI have a demonstrated coefficient of friction as low as 0.08 under sliding conditions in bovine serum.
Adhesion of the DLC coating to metal surfaces, a problem for most DLC methods, is excellent when an SwRI-developed bond coat (patent pending) is used. Recent research has shown that DLC is a highly biocompatible and blood-compatible material, and that it is probably at least as non-thrombogenic (nonclotting) as pyrolytic carbon.
The Institute's Ion Beam Surface Modification Facility is one of the largest in the United States, with a macroscopic beam capable of simultaneously coating hundreds of small components. Complex parts can be rotated under the beam to permit uniform coating. Currently, DLC is being used for such robust applications as cutting tools, and is also the subject of ongoing applied research for use in orthopedic and cardiovascular implants. Other candidate applications include catheters, surgical seals, and stents.
For more information about DLC coating process, contact Deborah J. Deffenbaugh, Communications Department, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510, Phone (210) 522-2046, Fax (210) 522-3547.