The internal energy of the cubic polytype is slightly lower than that of the hexagonal form and growth rates from molten material in both natural and bulk synthetic diamond production methods are slow enough that the lattice structure has time to grow in the lowest energy (cubic) form that is possible for sp bonding of carbon atoms.In contrast, DLC is typically produced by processes in which high energy precursive carbons (e.g.
Quoting from that document: ] bonds can occur not only with crystals - in other words, in solids with long-range order - but also in amorphous solids where the atoms are in a random arrangement.
In this case there will be bonding only between a few individual atoms and not in a long-range order extending over a large number of atoms.
in plasmas, in filtered cathodic arc deposition, in sputter deposition and in ion beam deposition) are rapidly cooled or quenched on relatively cold surfaces.
In those cases cubic and hexagonal lattices can be randomly intermixed, layer by atomic layer, because there is no time available for one of the crystalline geometries to grow at the expense of the other before the atoms are "frozen" in place in the material.
In 2006, the market for outsourced DLC coatings was estimated as about 30,000,000 € in the European Union.
In October 2011, Science Daily reported that researchers at Stanford University have created a super-hard amorphous diamond under conditions of ultrahigh pressure, which lacks the crystalline structure of diamond but has the light weight characteristic of carbon. Sometimes there are lattice defects or inclusions of atoms of other elements that give color to the stone, but the lattice arrangement of the carbons remains cubic and bonding is purely sp.
For example, a coating of only 2 μm thickness of ta-C increases the resistance of common (i.e., type 304) stainless steel against abrasive wear; changing its lifetime in such service from one week to 85 years.
Such ta-C can be considered to be the "pure" form of DLC, since it consists only of sp The various forms of DLC can be applied to almost any material that is compatible with a vacuum environment.
A Co-alloy valve part from a producing oil well (30 mm diameter), coated on the right side with ta-C, in order to test for added resistance to chemical and abrasive degradation in the working environment.
Diamond-like carbon (DLC) is a class of amorphous carbon material that displays some of the typical properties of diamond.
The first 100 min shows a burnishing away from the coating of an overburden of soft carbons than had been deposited after the last cycle of impacts converted bonds to sp) bond angles may be distorted from those found in either pure cubic or hexagonal lattices because of intermixing of the two.