The bonding of protective films of amorphic diamond to titanium

Abstract

Films of amorphic diamond can be deposited from laser plasma ions without the use of catalysts such as hydrogen or fluorine. Prepared without columnar patterns of growth, the layers of this material have been reported to have ‘‘bulk’’ values of mechanical properties that have suggested their usage as protective coatings for metals. Described here is a study of the bonding and properties realized in one such example, the deposition of amorphic diamond on titanium. Measurements with Rutherford backscattering spectrometry and transmission electron microscopy showed that the diamond coatings deposited from laser plasmas were chemically bonded to Ti substrates in 100–200-Å-thick interfacial layers containing some crystalline precipitates of TiC. Resistance to wear was estimated with a modified sand blaster and in all cases the coating was worn away without any rupture or deterioration of the bonding layer. Such wear was greatly reduced and lifetimes of the coated samples were increased by a factor of better than 300 with only 2.7 μm of amorphic diamond.

Adhesion properties of amorphic diamond films deposited on zinc sulfide substrates

“…The diamond characteristics of these novel materials have been evaluated by several analytical methods. Measurements agree in supporting s p contents of better than 75% for the nominally produced films [3,5,6]. No other technique has been reported for the production of this material, and to date, the quenching of C+ beams available from the conventional ion beam methods onto a substrate has been shown to produce only low-quality carbon films [4,7].…”

“…Amorphic diamond films have been produced by accelerating and quenching an intense laser plasma of C3+ and C4+ onto a cold substrate [1][2][3][4][5][6][7][8][9][10]. Prepared entirely without hydrogen, fluorine, or any other catalyst, these films are composed of hard dense nodules with grain sizes of the order of 20-100 nm.…”

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

“…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.…”

“…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.…”

“…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].…”