Protective coatings of nanophase diamond deposited directly on stainless steel substrates

Abstract

Composed of sp3 bonded nodules of carbon, nanophase diamond films are deposited in vacuum onto almost any substrate by condensing carbon ions carrying keV energies. These multiply charged ions are obtained from the laser ablation of graphite at intensities in excess of 1011 W cm−2. The high energy of condensation provides both the chemical bonding of such films to a wide variety of substrates and low values of residual compressive stress. Coatings of 2–5 μm thickness have extended lifetimes of materials such as Si, Ti, ZnS, ZnSe, and Ge against the erosive wear from high-speed particles by factors of tens to thousands. In this research emphasis has been placed on studies of the bonding and properties realized by the direct deposition of nanophase diamond films on stainless steel substrates. Examinations of interfacial layers showed deep penetrations of carbon atoms into steel substrates. Resistances to low and high impact wear estimated by a tumbler device and a modified sand blaster, respectively, and results indicated significant increases in the lifetime of stainless steel samples. The characterization studies in this work demonstrated nanophase diamond as an attractive material for use as a protective coating in current industrial applications.

Low-Impedance Compact Modulators Capable of Generating Intense Ultra-fast Rising Nanosecond Waveforms

“…The diamond character has been confirmed by the agreement of structural morphology, density, optical properties, K,, line energies and hardness. Since it is produced under conditions that are also optimal for the growth of interfacial layers, the films of amorphic diamond are strongly bonded to the substrates onto which they are condensed [11,12].…”

(New World Vistas) Research on Intense, Photoconductively-Switched Stacked Blumlein Modulators to Supply Ultra-Wideband HPM Systems

“…Basic research in our laboratory has described a conformal coating that has hardness of natural diamond and exceptionally high values of electron emissivity [14][15][16][17][18][19][20][21]. Discovered at UTD, it is made from graphite and laser light without catalyst, noxious byproduct, or toxic wastes.…”

“…The experimental conditions used at UTD to deposit films of amorphic diamond have been described previously [14][15][16][17][18][19][20][21]. A Q-switched Nd-YAG laser was used to deliver 250 -1400 mJ to a graphite feedstock in a UHV system at a repetition rate of 10 Hz.…”

“…Values of compressive stress measured in finished films of micron thickness are low for amorphous materials, being 0.5 to 0.8 GPa. Since it is condensed from laser plasmas produced under conditions, which are also optimal for the growth of interfacial layers, the films of amorphic diamond are strongly bonded to the substrates onto which they are condensed [14][15][16][17][18][19][20][21].…”

Nucleation and growth microstructural study of ti films on 304 SS substrates

“…As a consequence of surface smoothness, hardness and chemical inertness, the use of diamond polycrystalline films as protective coatings for steel materials is highly desirable and technologically relevant. However, nucleation of the diamond phase is extremely difficult on these material surfaces mainly because of the high diffusivity of carbon ions into steel substrates at temperature used to obtain CVD diamonds, which consumes the carbon species needed for nucleation of diamond phase [4][5][6][7] . In order to enhance nucleation density, the growth of polycrystalline diamond films and the adhesion of these coatings on steel, the creation of a carbon diffusion barrier near or on the surface of the substrate is required.…”