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Stupid question about blade materials.

Jan 12, 2001
My roommate and I were having a discussion on blade materials and he suggested that a blade impregnated with diamonds or a tipped with carbite would be the ideal material for a strong/sharp as hell blade. Something about it just doesn't sound right to me, but I couldn't come up with a good reason why it wouldn't work, besides it not being cost-effective. Can anyone enlighten us?

andy vesik
-me and my dislocated brain.
It's not a stupid question at all. In fact, part of the answer is, that's how steel does it. The other metals alloyed with it also form carbides which act as microserrations. That's how the cobalt alloys like Talonite work, also. The metals themselves may be soft, but the carbides give it that bite, and the metal wearing away just reveals fresh carbides at the new edge.

As for diamond, why bother? Expensive and troublesome. As anyone who's used a diamond encrusted sharpener can tell you, it works fine till the diamonds wear away.
In trying to explain what knife steel Is, I sometimes use the analogy of having diamonds embedded in a hard dense plastic matrix.

The diamonds represent the carbide crystals in the steel. Various alloying agents (chromium, vanadium, tungsten, etc) help make different kinds and sizes of carbide crystals. These are very hard and do the actual cutting at the edge. The matrix that surrounds the carbides is primarily an amorphous (glass-like and non-crystalline) matrix of iron called cementite. The ratio of carbides to cementite can be manipulated by changing the carbon content and other alloying elements. Heat treatment (annealing, normalizing, hardening, and tempering, or softening) determines the final physical make-up and working properties of the steel by manipulating the size and way the elements in the steel combine to form carbides.

A pure carbide blade would Not be very tough. It would be extremely brittle and prone to failure from the slightest lateral stress. The purpose of various steel alloys is to attempt to achieve some sort of balance between edge holding, and toughness. Most steel alloys have been adapted for use in knife blades. Their original purpose is for making tools to make other tools (tool and die industry), or in the making of bearings. The working properties of the steel as intended for use as a bearing would be very different from the physical properties of the same steel when heat-treated for use as a blade steel.

As for imbedding diamonds in steel to make blades, it sounds very expensive and would probably not work very well unless a source of ultrafine diamond dust could be inexpensively manufactured. In the medical industry, it is fairly common to see tools with carbide cutting edges and gripping surfaces. This will greatly extend the life of the tool without requiring re-sharpening. This is Not done with scapel blades however. These are usually made from high chromium steel alloys and are thrown away after use.

Hope this helps. Great question vesik!


[This message has been edited by Paracelsus (edited 01-23-2001).]
I am not sure if this along the same lines of what you are thinking or not, but, here goes.

Henckels introduced a new kind of knife to their line-up about 3-4 years ago called Twinstar. It had a more ergonomic handle design and the big thing was what they called a MagnaDur edge. They apply a coating to the edge to make it stay sharp for, they say, about 1000 times longer than a standard edge.

A fellow cook I knew at the time went out and picked one up. After he had had it for a couple of days I asked him what he thought. He stated that it did hold it's edge without any effort. But, you couldn't do anything to the edge yourself. If you try to sharpen it, evidently you ruin the coating and the whole point of having it in the first place. And it was not as sharp as his other knives, it was alright but not like he preferred, it could not be made any sharper than it came out of the box. About a week later he went and took it back and bought something else instead.

they now offer that same handle style in a knife without the MagnaDur. They also still offer the MagnaDur in what they are now calling their Twinstar Plus line.


If you go here and scroll down it will show you what little info they have published on it. Hope this gives you something else to think about that will help.

Take care.

one of these days I will learn how to post a link right the FIRST time!

Also I didn't realize that the link would not take you directly to where I was discussing. Hit the 4th line down "the material", then hit the 4th line down again "quality starts with the material", Then scroll down. Sorry.

[This message has been edited by Andy Wilson (edited 01-23-2001).]

[This message has been edited by Andy Wilson (edited 01-23-2001).]
Carbide and Diamond are actually that different. So, a good steel is actually almost diamond impregnated.

Diamonds are a very hard material (the hardest naturally occuring substance on Earth). But hard is not always a good thing. Being very hard also makes diamonds very brittle. Large diamonds can actually shatter just from being dropped.

Balisongs -- because it don't mean a thing if it ain't got that swing!
There are "new" so called "nano particle carbides", which actually contain extremely fine diamond particles, sintered in nickel.
The rumor goes, they are about 10x as edgeholding as conventional carbides.
I have not used them, so this is just "hear say".
These very tiny particles are by no way brittle and as nickel is "wetting" diamonds they are not easily torn out.
Remark: they are used with quite obtuse angles for HD metal-cutting, not for knives.
Happy sharpening