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  • Electronic Resource  (2)
  • 2000-2004
  • 1995-1999  (2)
  • calcium phosphate  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 37 (1997), S. 60-67 
    ISSN: 0021-9304
    Keywords: heat treatment ; calcium phosphate ; coating ; sputter ; implant ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: This study evaluated the effect of rapid heating with infrared radiation on the physico-chemical and morphological properties of radio frequent (RF) magnetron-sputtered calcium phosphate (Ca-P) coatings. About 2.5 μm thick Ca-P coatings were deposited on titanium disks and cylinders. These specimens were left untreated or were heat treated by infrared radiation at 300, 400, 500, 600, and 700°C for 4, 7, 11, 17, and 24 s. Subsequently, the specimens were immersed in simulated body fluid (SBF) for 1 day, 1 week, and 5 weeks. X-ray diffraction measurements showed that heating at 500°C or higher resulted in an increase of coating crystallinity. In addition, FT-IR measurements revealed the appearance of OH peaks in the spectra of samples treated at 500-700°C. Electron probe microanalysis showed that after 5 weeks of immersion about 40-50% of the coatings heat treated at 500 and 600°C was maintained. The coatings heat treated at 700°C showed no dissolution at all. On the other hand, as-coated and 300°C treated films were dissolved within 1 day. Scanning electron microscopy of the samples showed that directly after heat treatment no apparent cracks were present in the coatings. On the basis of these findings, we conclude that rapid heating with infrared radiation around 600°C is the best heat treatment for RF magnetron-sputtered coatings. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 60-67, 1997.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 42 (1998), S. 266-271 
    ISSN: 0021-9304
    Keywords: calcium phosphate ; ion beam analysis ; coating ; Rutherford backscattering ; elastic recoil detection ; biomaterial ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: RF magnetron sputter deposition was used to deposit thin calcium phosphate (hydroxyapatite) layers on titanium alloy substrate material. We determined the precise amount of calcium, phosphorus, oxygen, and hydrogen in these films by combining two ion-beam analysis techniques: Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD). Variables were power level, partial oxygen pressure, or additional water vapor. Also examined was the influence of additional bias power to the substrates during deposition and the effect of annealing on the final composition of the deposited layers. Measurements showed that the Ca/P ratio decreased with increasing oxygen pressure or decreasing sputtering power. In addition, the Ca/P ratio increased when a bias was applied to the substrates. The O/P ratio of the films decreased with additional oxygen pressure but increased when additional water vapor was applied during deposition. All as-deposited films showed a higher hydrogen content than stoichiometric HA. The hydrogen content in the films deposited with water vapor was more than 7 times higher than in the films deposited under pure argon conditions. After annealing, the hydrogen content decreased to about 3.5 at % whereas in stoichiometric HA the hydrogen content amounts to 4.5 at %. After annealing, the oxygen concentration in the film also decreased. We assume that hydrogen disappears out of the film as H2O during annealing. For the targets used in these experiments, sputter deposition at 400 W, with additional water vapor and annealing at 500°C, produced films with a stoichiometry closest to that of hydroxyapatite. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 42, 266-271, 1998.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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