I'm a materials junkie. My wine glasses are made of ZrO2 stabilized by Y2O3. My daily work is to convert carbon-bearing gases into diamond through plasma chemistry. I've long considered making diamond knife blades, although recent literature searches have put me off a bit, given their demonstration that brittle ceramic blades like Zirconium oxide shed sharp microparticles that I doubt are good for the ingester.
Nevertheless, I have made several small solid diamond blades (~15 cm long) that I've used to cut filet mignon. With load cells attached, the draw force to cut with a diamond blade is <20% of the draw force needed for an equivalent steel blade coated with titanium nitride and overcoated with a thin Teflon layer, about 5% of the draw force required by a custom Japanese knife. I have one diamond blade in my kitchen that I use as a paring knife. It's the very best tool I own.
I'm gratified that our ancestors figured out how to make superlatively sharp blades knowing essentially nothing of the science underlying their work. They were very smart and attuned to the aesthetics of their work.
Thanks again for the post. Materials are endlessly fascinating.