Talk:Diamond-like carbon

Discussion of Major Revisions

The continued appearance of new participants in the building of an article is always heartening. However such generous contributions of time and attention can sometimes move into stylistic differences of opinion. Myself, I think pictures help make the Wikipedia more attractive, interesting, and they are worth the effort of inserting them. It is time consuming to add pictures but very easy to delete them. Because of this asymmetry I think the policy of consensus, WP:CON is particularly relevant. The photograph of the Golden Jubilee Diamond has been a part of this article for more than a half of a year and represented some sort of consensus. It may be irrelevant, but maybe not, so I would propose we follow the path toward another consensus by discussing major changes before making them as recommended by established guidelines WP:TPG. Here I start this discussion and then revert the last edit putting the picture back. I think that I originally added the picture in question with the idea to help the non-specialist conceptualize the difference between inclusions in a perfect crystal lattice such as those that give this particular diamond such a strong color and the effect of a whole different lattice like the change to hexagonal diamond. Unfortunately the latter does not produce anything that can be photographed, or at least I cannot find a photo. I propose that the picture is a positive addition to the article, has no specific downside, and should remain. Let's talk about it here. --Drac2000 13:40, 9 May 2007 (UTC)

Please remove the diamond. Synthetic diamond != DLC. The pic (while looking attractive) is misleading. --Dschwen 15:50, 9 May 2007 (UTC)

OK. The article is reverted back to the last edit by Iepeulas and a more appropriate photo has been added. --Drac2000 16:03, 10 May 2007 (UTC)

Nice pic, thanks! I could supply pictures of thin DLC films deposited with mass seperated ion beams. --Dschwen 16:24, 10 May 2007 (UTC)

Sounds great! Please add one. --Drac2000 00:21, 11 May 2007 (UTC)

Tribological Properties

I rewrote the tribology section. The old section contained very little info on the tribology of DLC itself, it was mostly stuff paraphrased from the tribolgy article.Iepeulas 22:09, 4 August 2007 (UTC)

TEM micrograph source?

The Ta-C structure TEM image (http://en.wikipedia.org/wiki/Image:Ta_C_structure.jpg) appears in an article by Collins et. al., Journal of Vacuum Science and Technology B, v.11, p. 1939. It is cropped differently and flipped left-to-right, and credited "courtesy of J. C. Pivin, CSNSM, Orsay, France". Clearly both images were captured at the same time and from the same sample. This image needs a better citation so that its copyright status can be verified. 129.78.64.101 05:30, 18 September 2007 (UTC)

Since the Wikipedia encourages the inclusion of figures in articles, there is good news that this figure has been so widely reprinted that there can be no plausible challenge to its status of being in the publc domain. It has been left alone in Wikipedia for about a year providing a useful visual of diamond nodules which differ considerably from diamond crystals. Inconveniently enough, the above citation by 129.78.64.101 did not follow usual standards by including the year of publication, which was 1993. It had been published several different times in 1992 and other places in 1993 and later. Depending upon the page format, restrictions on publication length, etc., it was naturally formatted, and scaled. Original data is not copyrighted in this field and the first image from the data was a negative, neither reproduced nor copyrighted. Because it was a particularly illustrative example of nodular structure, various prints from the negative were reproduced widely in reviewed publications, as a type of standard. Evidentally it was turned over during one such printing. Of course, the critical question is the accuracy of the scale which had to be inserted and happily I know of no example in which this step was poorly executed resulting in a misleading size for the important structural nodules. Hopefully, this explanation will suffice but if not, what needs to be done? --129.110.241.121 15:55, 18 September 2007 (UTC)

Aside from the issue of whether or not the image is in the public domain, or whether this is an example of fair use, I still think the source should be acknowledged. Firstly, if people want to find out more details of the film shown--the deposition parameters and system, or the substrate used, for example--they will know where to look. Secondly, the group that deposited and imaged the film should be given appropriate credit. I assume (from the dates quoted above) that first publication was Collins et. al., Journal of Applied Physics 71 (7) p.3261 (1 Apr. 1992!) and if this is the case the picture should say so. Regards, 129.78.64.106 00:21, 19 September 2007 (UTC)

The date sounds about right, but there were so many expositions of prints from that negative there might have been earlier talks and conference proceedings. Please add whatever you judge is best for crediting and establishing "fair use," or whatever catagory solves the problem that you perceive. Then we can see who may object because they are better informed. I understood that was the style of Wikipedia, but I am not much involved with it. --129.110.241.121 16:06, 19 September 2007 (UTC)

History

It would be nice to know when this was developed. I believe the Soviets were using this in the 1970s, but probably not invented there. — Preceding unsigned comment added by 24.16.88.14 (talk) 05:45, 4 September 2011 (UTC)

Heinz Schmellenmeier was the first to produce a diamond-like coating on drills in 1953. You can find his biography in the german Wikipedia. 178.165.129.230 (talk) 18:30, 4 June 2014 (UTC)

Factual Error: sp2,sp3 bond lengths

Wikipedians,

I'm not familiar with the culture here, so that's why I'm not just editing the article.

Nevertheless, the first sentence in the "Production" section, "There are several methods for producing DLC, but all depend upon the fact that in carbon the sp3 bond length is significantly less than the length of the sp2 bond," is factually incorrect.

As is correctly shown in a table on this page, http://en.wikipedia.org/wiki/Bond_length#Bond_lengths_of_carbon_with_other_elements, the sp2 bond length is shorter than the sp3 bond length. Diamond-like structures are favored at high pressure because the density of sp3 carbon is higher than the density of sp2 carbon. The density is higher not because the bond length is shorter, but because the bonding geometry is quite different (tetrahedral over trigonal planar) in a way that leads to tighter packing.

Robert McGibbon | Stanford University | Graduate Student | Department of Chemistry — Preceding unsigned comment added by Rmcgibbo (talk • contribs) 05:24, 16 October 2012 (UTC)

Quickfixed, thank you. Materialscientist (talk) 05:37, 16 October 2012 (UTC)

85 years?

How come that adding just another micrometer of coating extends the lifetime from a week to 85 years? This is a very unproportional increase (from 52 times for the first micrometer to 4420 times for the second micrometer).

Lee-0 (talk)

Perhaps if the writer had cited any of the many wild claims, we could find out. Add a citation needed tag. I have a feeling this page is more of a marketing advertisement than an actual scientific review. Eframgoldberg (talk) 06:00, 18 April 2017 (UTC)

Errors in Production section

There seems to be a misunderstanding of general chemistry in this section. sp3 and sp2 are hybridizations of the molecular orbitals. The difference between the two allotropes of diamond, cubic or hexagonal, have nothing to do with sp2, in pure substances, all carbons are tetrahedral sp3s. sp2 carbons are trigonal planar and found as graphene. I believe one production method involved transforming graphene into a mixed cubic/hexagonal sp3 diamond layer thay may contain residual graphene. I dont know enough about this material tp rewrite the section, but as a chemist, there are a lot of incorrect statements in this section. Eframgoldberg (talk) 05:58, 18 April 2017 (UTC)

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Disappointing quality

After having read a couple journal articles, it's clear this article is not in great shape. A plausible recent survey seems to be https://www.sciencedirect.com/science/article/pii/S0257897214000474 History of diamond-like carbon films — From first experiments to worldwide applications I can't evaluate some of the other criticisms in talk, but it does seem that a lot of the content here emphasizes ta-C films, with primarily tetrahedral bonds and low hydrogen, as the "real deal" and implies that everything else is a shoddy substitute (dilutient), while as I understand it, the majority of the DLC coating business is based on coatings with high hydrogen content. It is true that ta-C is most diamond-like, but other coating qualities are important too, like sticking to the treated surface, and production cost.

Also, the bit at the end of the introduction about amorphous carbon in diamond cell research has little or nothing to do with DLC coatings. Robertmacl (talk) 01:00, 28 March 2018 (UTC)

Also the new 2021 reference to a Chinese paper with films able to scratch diamond, claiming to be a world first - I remember Russian papers showing this from over 20 years ago. There's a whole chapter in "Comprehensive Hard Materials edited by Daniele Mari, Luis Miguel, Christoph Nebel" discussing related materials. There's an image of scratched diamond from fullerites in Blank, Reshetov et al, Diam. Rel. Mater. 7, 427 (1998). 92.88.250.45 (talk) 06:18, 22 June 2022 (UTC)