I read that a thickness of one micrometer of DLC coating (which, if I understood correctly, shows similar properties to diamond), increases the lifespan of an item plated with it from a week to more than a year, while a thickness of two micrometers can increase it up to 85 years. enter link description hereI find this difficult to imagine, as we all know cases of jewelry plated with a thin layer of gold, which loses its luster sometimes and after several months of use. Besides, it has occurred to me that every time any object is touched, it loses billions of atoms. If this is the case, are the atoms in diamond and DLC so tightly bound together by bonds that the material is actually so resistant to any major weight loss?
1 Answer
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If properly applied (which is not easy) diamond-like coatings can be as hard as diamond itself, in which the carbon atoms are extremely tightly-bound to one another and hence form an extremely hard, abrasion-resistant film.
But if the diamond-like coating is applied on top of something softer than diamond (which means any material at all), it's possible for the material under the DLC to deform under load, causing the DLC to crack and flake off. This limits the applications of DLC.
FYI in the early days of DLC technology it was known as "diamond-like carbon" and was so difficult to create that most batches wound up being a substance we called "carbon-like carbon". This is a materials science joke; you may now laugh.
answered Mar 15 at 17:23
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$\begingroup$ Thank you! Does this mean that the atoms are so strongly bound together by covalent bonds that it is hard to break them apart? The size of a carbon atom is 70 pm. The thickness of the DLC coating is 1-3 micrometers. I am a complete layman in matters related to this subject, so it surprises me that a 3 micron coating can last even a few years. I thought that even every time we touch an object with my hand that is properly coated with DLC coating, we rub off a few billion atoms from its surface, and it does not seem time-consuming to completely wipe off such a thin coating in such a case. $\endgroup$ Commented Mar 15 at 17:34
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$\begingroup$ the carbon atoms are far too tightly bound to be wiped off like that. The idea that billions of atoms get wiped off with each touch might be true for orange peels and skin but it is definitely not true for diamond. $\endgroup$ Commented Mar 15 at 18:53
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$\begingroup$ If so, is it possible to speculate how many carbon atoms we wipe off the surface of the diamond with each touch? Would it be millions, billions, or perhaps trillions of atoms? $\endgroup$ Commented Mar 16 at 14:39
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$\begingroup$ I do not know how to estimate that. $\endgroup$ Commented Mar 16 at 17:48