Mechanical Properties of Laser Processed Diamond-Like Carbon Films
- PDF / 327,397 Bytes
- 7 Pages / 414.72 x 648 pts Page_size
- 75 Downloads / 242 Views
ASHOK KUMAR*, R. B. INTURI**, Y. VOHRA***, U. EKANAYAKE*, N. SHU*, D. KJENDAL*, G. WATrUHEWA*, and J. A.BARNARD** *Department of Electrical Engineering, University of South Alabama, Mobile, AL 36688 "**Departmentof Metallurgical and Materials Engineering, University of Alabama, Tuscaloosa, AL 35487-0202 ***Department of Physics, University of Alabama at Birmingham, Birmingham, AL 352941170 ABSTRACT
Diamond-like carbon (DLC) films have a unique combination of physical and chemical properties such as high hardness, optical transparency, low coefficient of friction and chemical inertness. A pulsed laser (248 nm) has been used to ablate a pyrolytic graphite target to deposit DLC films on Si (100) and 7059 Coming glass substrates. The deposition was carried out in high vacuum (< 10-6 Torr) at different temperatures ranging from room temperature to 400'C. The films were characterized by x-ray diffraction, scanning electron microscope, and Raman spectroscopic techniques. The mechanical properties (hardness and Young's modulus) of these films were characterized by nanoindentation. We have found that the films deposited at room temperature and 100°C show the characteristic features of DLC films and have the better hardness and modulus properties compared to the films fabricated at higher temperatures, which transform into amorphous carbon. Correlations of pulsed laser deposition process parameters with the properties of deposited DLC films will be discussed in this paper. INTRODUCTION
Diamond-like carbon (DLC) films have generated interest due to the unique properties of the materials. The durable, smooth, adherent films are quite transparent and impervious to reagents which dissolve graphite and polymeric carbon structures. These amorphous films have desirable characteristics similar to those of diamond such as, extreme hardness, high transparency (both at visible and infrared wavelength), high electrical resistivity, low coefficient of friction, and chemical inertness. These combination of attractive properties make DLC films for a wide variety of applications. These include high transmission optical coatings, hard coatings for cutting tools, and low friction films for aerospace components [1, 2]. A number of researchers have demonstrated that DLC films may be obtained by vaporization of graphite targets by the pulsed laser deposition (PLD) method [3, 41. In all of these, deposition of unhydrogenated DLC requires the depositing species to be energetic. These films are amorphous, hard, optically transparent, chemically inert, and high in resistivity. Since they are prepared without hydrogen, they have a higher density and index of refraction than the hydrogenated DLC films obtained by hydrocarbon plasma deposition processes. The hardness and elastic modulus of the films are important materials properties to determine the potential applications in commercial sectors. The results of mechanical properties are compared with existing data on DLC deposited using PLD and other techniques. 289 Mat. Res. Soc. Symp. Proc. Vol. 397
Data Loading...
