Question regarding Ceramic knives

T

TimmyQuestionsBlades

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Dec 26, 2022
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Greetings and thank you in advance for your help,

Allow me to summarize this Christmas' huge "debate" between myself and two other family members. Keep in mind that I have no experience with knives and I am not afraid of being corrected provided there's evidence to back it up.
We were talking about knives, and one of my family members claimed that he bought "a ceramic knive made of metal/steel (he used both interchangeably throughout the discussion) 25 years ago" and furthermore that "ceramic means folded" although at a later time he corrected it to "pressed".
I am of the understanding that a ceramic knive *can not* be metal or metallic by the very nature of the definition. Even a tungsten carbide knive or titanium carbide knive would not be considered ceramic nor metallic, but a ceramic-metal alloy, which is a different concept altogether, and at least tungsten carbide knives have not been a thing for more than 10 years, tops.

It is also claimed that this ceramic knive would be able to "chip off small pieces and remain sharp, never having to sharpen it". The knive is a scuba knive.

I would appreciate any insight on the subject and any corrections in my belief that either this person is confusing terms or if as he claims to remember this being exactly what he was sold, being lied to.

I would also like to see a modern example of a "ceramic knive" made of metal and/or steel.

Thanks once again and happy holidays!
 
TC said:
Ceramics do not "alloy" with metals.

Your relative confused ceramic with damascus it seems. A ceramic has a glass-like microstructure, i.e. it is amorphous, not crystalline.
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In my research today I have found that tungsten carbide and titanium carbide classify as ceramics, but not as metals even though tungsten and titanium are metals. There is not much knowledge to be found in a few hours of research of course, but can anyone expand on this to a lay-man?
 
TimmyQuestionsBlades said:
In my research today I have found that tungsten carbide and titanium carbide classify as ceramics, but not as metals even though tungsten and titanium are metals. There is not much knowledge to be found in a few hours of research of course, but can anyone expand on this to a lay-man?
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The key word here is carbides.

Tungsten and titanium carbides are used in a process of vapor deposition as a very hard coating for wear resistant on steel blades. This is different from a metal alloy with dissolved elements through out the blade stock. Some are almost as hard as diamonds. I don’t know a lot about it but the ceramics I’m familiar with are not in a metal stock alloy of any thickness only as a very thin coating. I have a few in aluminum titanium nitride. I’ve seen a few ceramic knives but they are like a ceramic cup and they are brittle and don’t stand much force to break.
 
Ceramic knives get complicated. Most are a mixture of Aluminum and Zirconium oxide. These are brands like Kyocera and similar products.

Ceramics can be “alloyed” similar to metals. Most ceramics are crystalline and have grains like metals do. Amorphous materials are generically referred to as glasses, and there are metallic, ceramic, and polymer amorphous materials (glasses). Obsidian knives are “glass” knives.

There are tungsten and titanium carbides deposited on blade surfaces and there are now knives made of cemented carbides like tungsten carbide in a metallic binder, typically cobalt.

Ceramics and cemented carbides are extremely wear resistant. They are also extremely brittle. This is their main drawback. Dropping one of these knives risks ending up with more knives than you started with.

Sharpening these materials is different. These materials do not form burrs nor do they work well with coarse edges or very low edge angles. High polishes, diamonds, and power equipment are your friends.
 
This thread fits in here as well:

Forever SC-16WB ceramic knife

Some time ago while surfing the net i found a website with Catra test results for 3 different ceramic knives: two by the well known Japanese Kyocera brand, and one from another (and unfamiliar to me) Japanese brand with the name Forever Company. Next to various types of ceramic knives the...
www.bladeforums.com www.bladeforums.com
 
This knife has a tungsten carbide blade. It feels like metal and is attracted to a magnet, but I'm not sure how to classify it. It is not steel though. It is definitely not folded, pressed or sintered, maybe.

EDIT- In doing a quick Google search for "is tungsten carbide a metal", some say metal, some say ceramic, and one said ceramic-metal hybrid.

H7Z30LH.jpg
 
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I have some ExoTac NanoStrykers that demonstrate the lack of Ferromagnetism (attracted to magnet) property of Tungsten Carbide. The older models have 440-C strikers that are attracted to a magnet. The newer models equipped with Tungsten Carbide strikers are not attracted in the slightest. This is a good test to see if you have the old “soft” strikers or the new “hard” strikers. The 440-C is around 60HRC; the WC (Tungsten Carbide) is around 72HRC.View attachment 2028386
 
I would be a bit worried about using a ceramic knife as my only tool/knife for scuba diving, as there may be occasions when you want to use it for prying and the ceramic blade might snap.
 
22 or so years ago, Kevin McClung of Mad Dog knives made a ceramic knife called "The Operator" - or something silly like that.

(here it is - Operator Mirage X.)
He hyped it up as being "Undetectable by airport scanners" - so - he had to add a metal strip inside the ceramic so it could be detected.

That's very likely the origin of a steel/ceramic mix knife.

It could also be they are thinking of Talonite and/or Stellite.
Non-steel Talonite was supposed to set the knife world on fire. The late Dr. Walt Welch & the late Rob Simovnch & Kit Carson were probably the three most well-known champions of Talonite .
Walt & Rob both passed away & the whole Talonite craze pretty much went with them.
I believe Tom Waltz from Carbide Processors had his hand in it also. Maybe as a supplier?
You can email Tom @ Carbide Processors if you want. He's probably one of the four nicest people in the world & he forgot in the last 10 minutes about carbide than any 1000 people in that line have ever known.

"Chipping off small pieces to remain sharp" - that isn't ceramic, that's glass. More precisely, Obsidian.
Obsidian is probably the sharpest edge there is. just google it for the specifics.
.

Oops - hit submit too soon.
Ceramic blades are - a mixed blessing. I have one that's easy, 15 years old. It can still slice a tomato without having to "start the cut" if you know what I mean. It does have a big ugly chip in the blade & the point is snapped off.
I don't know when that happened & what's worse is, I don't know what happened to the chips. That's a seriously scary thing. That's the biggest reason I only use ceramic for limited things.
They stay sharp forever - but - they break real easy.
 
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Thanks guys (and possibly gals?), I appreciate all the information. What I am getting at is that his knife most likely was *not* a ceramic knife, in the common use of the word, but a steel knife that maybe had some sort of carbide edge on it, which I wouldn't call a ceramic knife to be honest. I have yet to see this knife, but when I do I will drop it on the floor and if it breaks apart I'll agree with him that it's at least ceramic. Then I'll test for ferromagnetism and weight, I guess... Or I'll just leave the whole thing and appreciate the new knowledge. I am still interested in knifes from 25+ years ago that could possibly fall into a category of a knife-ceramic hybrid blade.

Happy soon-to-be new years!
 
Glenn Goodlett said:
This knife has a tungsten carbide blade. It feels like metal and is attracted to a magnet, but I'm not sure how to classify it. It is not steel though. It is definitely not folded, pressed or sintered, maybe.

EDIT- In doing a quick Google search for "is tungsten carbide a metal", some say metal, some say ceramic, and one said ceramic-metal hybrid.

H7Z30LH.jpg
Click to expand...

Your knife is a Sandrin Knives Monza model. Tungsten Carbide is a very hard Metal material, around 71 HRC but brittle and therefore not suitable as a sport or diving knife.

What is most commonly referred to as tungsten carbide is actually tungsten carbide grains cemented together with another metal material. The metal that cements or binds the tungsten carbide grains is typically cobalt. Nickel, nickel-chrome alloys, and iron can also be common binders for tungsten carbide grains.

Every element in tungsten carbide is susceptible to magnetism. Some of the elements are far less susceptible than others. Iron is much more susceptible to magnetism than cobalt, and cobalt is more susceptible than nickel. Tungsten, by itself, has very, very little susceptibility to magnetism. Different grades of tungsten carbide have different amounts of binder in them. The type and amount of each metal that make up the tungsten carbide determines how magnetically responsive the tungsten carbide will be.

By choosing a grade of tungsten carbide that is made up of a very small amount of binder can help ensure that the tungsten carbide is less responsive to magnets. If you need a material that will not react to a magnet at all, tungsten carbide may not be the best choice.

IMO, ceramics and things like TC make good kitchen cutlery but not so much sporting knives. I do have a diving knife that is non-magnetic , made of Haynes alloy no. 25. It is shown in this picture with a Randall 16 and a Mission Knives MPK-12.
 
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