8 Diamond-Like Carbon Films Available to Purchase

Carbon as an element constitutes the building block of some of the hardest materials (such as diamond, boron carbide and transition metal carbides) known to date. It is also a key ingredient of amorphous diamondlike carbon (DLC) and carbon nitride coatings, which offer exceptional friction and wear properties to sliding, rolling or rotating surfaces [1, 2, 3, 4, 5]. Besides diamond and DLC, other carbon-based tribo-materials (such as graphite, graphite fluoride, glassy carbon, polymer, metal or ceramic-matrix composites, and carbon-carbon or carbon-graphite composites) have also been used to combat friction and wear for quite some time [6, 7, 8, 9, 10, 11, 12]. In particular, graphite, graphite fluoride and glassy carbons are effective in reducing sliding friction and wear of machine elements and, hence, are used extensively by industry as solid lubricants [4, 5, 6, 7, 8]. Carbon-based composites are also an important class of tribo-materials, providing some of the lowest friction coefficients and high resistance to heat [11]. The low-friction carbon composites are primarily used as seal materials by the rotating equipment industry, while the high-friction carbon-carbon composites are used to make high-performance brakes for racing cars and various aircraft [13]. Figure 1 shows some of the well-known carbon nanostructures and their applications in microtribological fields.

For the past three decades or so, numerous scientists have explored carbon as a precursor for the synthesis of superhard coatings like diamond, carbonitride and DLC (see [1] for a thorough review). In particular, diamond and DLC coatings have become extremely popular, mainly because of their exceptional mechanical, thermal, electrical and tribological properties. These films are now routinely produced by a wide range of chemical and physical vapor deposition methods and are used for numerous industrial applications, ranging from razor blades to artificial biomedical implants (such as hip and knee joints) [1, 14, 15].