What can it do?

In short, diamond-like carbon (DLC) can coat things and make them last forever.

DLC is harder than natural diamond and slicker than Teflon. That combination gets more horsepower from engines, longer lifetimes from mechanical parts that rotate and slide, survival of fragile optics in hostile environments, and it saves lives by making better medical options available.

Product development is a severely proprietary business. Nevertheless, we know that when pure DLC is used to coat medical implants and diagnostic probes, better results are obtained in living animals. Tests on the animals closest to human body chemistry, poor diet, and coronary deterioration have proven that DLC does not clot blood. Non-disclosure prevents the publication of actual data from implants, but a testimonial from the "recipient" is available.
DLC valve implant 
Final in vivo tests of coronary practice are made on pigs, not monkeys.
 DLC protects optics
Protection offered to fragile ZnS infrared (IR) windows by coatings of the pure DLC (ta-C). Windows are shown after 20 min. exposure to high-speed passage (760 km/hr) through a simulated rainstorm of 10 cm/hr. Not shown is an uncoated comparison window because it was reduced to small particles of ZnS sand scattered over the floor of the test chamber 
Hardness of materials and coatings is usually reported in metric units of GPa. It is a linear scale and twice as many GPa's is twice as hard. Some examples are interesting:  The cobblestone street analogy to the structure of pure DLC make it easy to see why it is a conformal coating. The nodules of amorphous diamond are linked in a flexible way. Like a mat or cloth with diamonds embedded in the mesh the coating can be smoothly wrapped around the item being coated. 
Examples of the numbers for hardness of several materials.
Material GPa
Common (304) stainless steel 3
The six types of DLC with fillers 9-30
Natural diamond 60-80
Pure DLC (ta-C) 60-130

The amount by which such a coating of pure DLC will increase the lifetime requires a formula.  Each layer of a given thickness being applied offers a certain attenuation of wear from the outside.  So the effects multiply each time the coating gets thicker by that same amount. Such a behavior is described by the expression:

 

where f is the factor by which the lifetime of a coated article is increased; g is a number that depends upon the nature of the wear, the material coated, and the content of filler in the DLC; and µ is the thickness of the coating in µm. A table of measured values follows.
Table of g-values for increases in lifetimes and critical thicknesses needed to increase lifetimes by 100 times. The critical thicknesses do not vary much.
Material sandblasted g value µ needed
for 100X increase
in lifetime
Silicon (Si) 35 1.3 µm
Titanium (Ti) 8.7 2.2 µm
Zinc sulfide (ZnS) 5.6 2.7 µm
Coating worn away in abrasive (SiC) slurry
304 Stainless steel 66 1.1 µm

A more extensive review of the matter of lifetimes can be found in the online "Encyclopedia" article at:

Diamond-like carbon at Wikipedia		 Sandblasting titanium.
Damage measured after sandblasting titanium (Ti) samples coated with pure DLC (ta-C)  for the times shown. Samples were tested with coating thicknesses of 0 (uncoated), 0.8 µm, 1.7 µm, and 2.7 µm. Damage was measured by laser light scattering. Horizontal axis in the middle shows a level of scattering corresponding to "failure" of the coating (ie. 10% of the maximum scattering observed. Vertical marks crossing that axis show the times expected from the formula predicting those lifetimes.

The critical point is that with pure DLC (ta-C) the lifetimes against wearing out can be increased by 100 times by applying from 1 to 3 µm (10% of the thickness of a human hair) in all cases studied. An increase of 100 times is an increase from a week to 2 years and from a year to a century.
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