The thing is, the very edge, i.e., the first about 5 micrometers, possibly up to about 20 micrometers, need to be strong enough. There are measurements on [0] t

The thing is, the very edge, i.e., the first about 5 micrometers, possibly up to about 20 micrometers, need to be strong enough. There are measurements on [0] that show how one can get a steel edge about 50 nm wide, and the same source claims 100nm to be necessary for cutting a free-hanging mustache hair. That "a triangular bevel with a 16 degree included angle is typically too weak to survive shaving a normal-to-heavy beard" [1] leads me to think that this coating is unlikely to reach the required thinness of the edge. You can buy utility knifes with such coatings, or at least I stumbled upon someone comparing different coatings on utility knifes, including diamond nano particles. Judging by the low life of such a sharp blade which 'just' cuts hairs, I don't think a coating will reach the target. And yes, the edge will be prone to shattering, but I never said I'd want to be careless with the knife, or never have to care for it. I just don't want to sharpen it more than once a week. If you look, the video I posted shows them hitting a rope, I assume nylon fibers, which certainly isn't that soft, and instead of shattering it results in an almost complete cut. For your carbide cutter you do have to remember that neither your cutter not the lip/bar was particularly likely to give in much. As long as it won't break if I cut a fish and hit a bone, it's not too brittle. I might need a softer cutting mat, but considering the (lack of) force I'd need, the softness shouldn't be much an an issue. And the cubic zirconia knifes I have do experience significant wear, judging by how quickly they lost their reasonably-sharp state and are no longer superior to a regularly sharpened (cheap) steel knife. One would probably need a hard-ish backing, e.g. maybe something like an edge-hardened steel blade, but with the thermal expansion coefficient matched to the diamond edge/insert. [0]: https://scienceofsharp.wordpress.com/2014/01/25/quantifying-sharp/ https://scienceofsharp.wordpress.com/2014/01/25/quantifying-... [1]: https://scienceofsharp.wordpress.com/2015/03/24/sharp-and-keen-part-2/ https://scienceofsharp.wordpress.com/2015/03/24/sharp-and-ke...