Biocompatible ultrananocrystalline diamond coatings for implantable medical devices
- PDF / 1,636,218 Bytes
- 11 Pages / 585 x 783 pts Page_size
- 67 Downloads / 231 Views
Synthesis and structure of ultrananocrystalline diamond films Diamond thin films are of great interest and are being investigated because of many current (e.g., diamond coated mechanical pump seals and bearings) and potential (e.g., microelectromechanical/nanoelectromechanical systems [MEMS/NEMS]) applications to enable a new generation of multifunctional devices.1 Several types of diamond thin films have been synthesized and systematically studied, exhibiting different microstructures, surface morphologies, and properties. Diamond films have been grown on the surfaces of insulators, semiconductors, and metals. Following surface pretreatment, or “seeding” (embedding micro- or nanodiamond particles on the substrate surface), diamond films are grown on the seeds mainly using microwave plasma-enhanced chemical vapor deposition (MPCVD) or hot filament chemical vapor deposition (HFCVD).1,2 For the MPCVD method, a mixture of gases is inserted into an air evacuated chamber, and microwave power is coupled to the gas to produce a plasma involving ionized and neutral atoms and molecules
containing C, H, and other components such as Ar. In the HFCVD process, an array of hot filaments heated up to 2200°C induces cracking of the CH4 molecules, producing radicals that induce the growth of diamond films.1,2 The use of a hydrogenrich chemistry (H2 [balance]/CH4 [0.1 to 4%])1,2 results in microcrystalline diamond (MCD) (1–5 µm grains and columnar microstructure) (for ∼1% CH4) and nanocrystalline diamond (NCD) (10–100 nm grains) (for up to ∼4% CH4) films. MCD and NCD films grown on surfaces of insulators (oxides), semiconductors, and metals seeded with diamond micro-/ nanoparticles without particle surface functionalization exhibit low initial nucleation densities (1012/cm2) using a seeding process involving functionalized diamond particles to avoid agglomeration,3 which is also used to grow relatively smooth, high-quality NCD films at 600–800°C.1,2 The H2/CH4 chemistry-based growth process is driven by CHx (x = 2–3) radicals interacting with the substrate surface.
Orlando Auciello, Materials Science and Engineering and Bioengineering Department, The University of Texas at Dallas, USA; [email protected] Pablo Gurman, The University of Texas at Dallas and the Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, USA; [email protected] Maria B. Guglielmotti, Oral Pathology Department, School of Dentistry, University of Buenos Aires, Argentina; [email protected] Daniel G. Olmedo, Oral Pathology Department, School of Dentistry, University of Buenos Aires, Argentina; [email protected] Alejandro Berra, University of Buenos Aires, Argentina; [email protected] Mario J. Saravia, Department of Ophthalmology, Hospital Universitario Austral, Argentina; [email protected] DOI: 10.1557/mrs.2014.134
© 2014 Materials Research Society
MRS BULLETIN • VOLUME 39 • JULY 2014 • www.mrs.org/bulletin
621
BIOCOMPATIBLE ULTRANANOCRYSTALLINE DIAMOND COATINGS FOR IMPLANTABLE MEDICAL DEVICES
This inv
Data Loading...
