Protective films of nanophase diamond deposited directly on zinc sulfide infrared optics

Abstract

Nanophase diamond films can be grown at room temperature with a laser plasma discharge source without the use of any catalyst. This technique produces films that adhere readily to materials for which there are important applications as protective coatings. Described here is a study of the bonding and properties realized with the direct deposition of nanophase diamond on the II-VI compound of zinc sulfide. It was shown that adhesion and mechanical properties of the films can be correlated with the amounts of defects and impurities in the zinc sulfide substrates. In all cases significant interfacial layers caused by the deep penetration of carbon atoms into the substrates were observed. Resistance to wear was estimated with a modified sand blaster, and results indicated that only 1 yum coating of nanophase diamond can increase lifetimes of the zinc sulfide samples by a factor better than 5. Protection afforded by the nanophase diamond under harsh environmental conditions of rain impacts was also described.

Nanocrystalline diamond: Effect of confinement, pressure, and heating on phonon modes

“…Proposed uses are far ranging and include semiconductor devices, hard protective coatings, nanocomposites, and nanobearings. [4][5][6][7] Raman spectroscopy has been shown to be a powerful probe of crystalline and noncrystalline phases, imperfections, and stress, to name a few. Two very interesting Raman effects in nanocrystalline diamond systems derive from confinement and internal stress.…”

“…6,7,19,20 One of the most technologically promising areas of research is in the thin film deposition of diamond, with applications in abrasives, protective coatings, and optical areas of technology. 4,5 Raman spectroscopy is a powerful characterization tool, being convenient, nondestructive, and extremely sensitive to many phenomena, including crystalline and noncrystalline phases, imperfections, surface effects, and stress. In particular, sp 3 -diamond, sp 2 -bonded graphite and amorphous carbons are readily detectable, making this technique effective in exploring the differences between natural and synthetic diamond.…”

Adhesion properties of amorphic diamond films deposited on zinc sulfide substrates

“…The general preparation of amorphic diamond has been detailed in the literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and only a brief review will be presented here. In all our work, films were deposited with the same laser plasma discharge system at the University of Texas at Dallas as previously described.…”

“…More impurity inhibited the formation of an interfacial layer. The protection afforded by the amorphic diamond under harsh environmental conditions of particle and rain impacts has been previously studied [15]. In this report, the role of Zn-C additives to the natural interlayer between amorphic diamond films and zinc sulfide substrates is investigated.…”

“…However, highly durable coatings are required to protect the substrates against the harsh environments in which they are most likely to be used. In a recent report [15], a study of the bonding and properties realized with the direct deposition of amorphic diamond on zinc sulfide was described. Analyses of the interface by Rutherford backscattering spectrometry (RBS) indicated that there was a significant intermixing of the substrate and the coating atoms.…”