Tungsten coating but no blades... Why?

I would imagine it's because it doesn't hold an edge all that well. You don't see many titanium knives because titanium doesn't harden well.
 
Because it is very brittle and very heavy. It is almost twice as dense as lead. It is what light bulb filaments are made of as well as TIG welding electrodes, both of which are fragile and break fairly easily. It is also expensive. I'm not sure what property would make you think it would be a good blade material because all those are terrible except maybe hardness.
 
Actually, I think the original poster was referring to the tungsten carbide in tungsten carbide-doped dlc coatings. While pure tungsten is ductile, tungsten carbide is very hard and brittle. Blades made of tungsten carbide are probably more akin to ceramic blades and all of the weaknesses inherent in them ie. brittleness/low-toughness, edge-chipping, difficult to resharpen, etc.

That being said, I do remember seeing special tungsten carbide blade replacements being sold for wood planers.

Other than making a entire blade from solid tungsten carbide (assuming the blade is larger than an xacto blade), a more viable solution maybe to make a blade with a tougher metal (steel, etc) and allow replaceable tungsten carbide edges to be somehow inserted/cemented/mechanically fastened to the blade (not unlike some circular saw blades, and wire cutters)....Of course this would make for an ugly, inelegant, and possibly impractical solution for a knife blade.
 
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Regarding Titanium blades: Beta-hardened Titanium can be brought up to the mid-forties on the Rockwell c scale. The Ti carbides in the blade, which do not affect the Rc rating, give the blade tremendous wear resistance. Ti carbides are some of the hardest carbides around. It would be like putting hard little stones in concrete to increase the wear resistance. Tungsten carbide is about 72 Rc. Solid carbide tools (like end mills) are often coated with TiAlN ( Titanium Aluminum Nitride) at 92 Rc to improve their wear resistance and heat resistance. I am not sure what TDLC (Tungsten Diamond Like Carbon) is. It is probably a ceramic coat like TiAlN or TiN.
 
tiguy7 said:
TiAlN ( Titanium Aluminum Nitride) at 92 Rc to improve their wear resistance and heat resistance. I am not sure what TDLC (Tungsten Diamond Like Carbon) is. It is probably a ceramic coat like TiAlN or TiN.
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Just a quick note:

The hardness of TiCN (Titanium Carbonitride) approaches 90 Rc, while TiAlN approaches 80-85 Rc (but performs better in high heat applications than TiCN).

The hardness of DLC coatings (doped with tungsten, titanium or steel) exceeds 90 Rc, has great lubricity, performs very well in high heat applications (although can still carburize substrates at extremely high temperatures like pure diamond cutters), and is generally starting to replace TiCN and TiAlN coatings.

The mentioned coatings use a form of either cvd or pvd (chemical or physical vapor depositation); mostly cathodic arc pvd.
 
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Sonny said:
. . . a more viable solution maybe to make a blade with a tougher metal (steel, etc) and allow replaceable tungsten carbide edges to be somehow inserted/cemented/mechanically fastened to the blade (not unlike some circular saw blades, and wire cutters)....Of course this would make for an ugly, inelegant, and possibly impractical solution for a knife blade.
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Off topic, I know:
FYI: Acme United/Camillus is doing this with a model called the Tigersharp. It's a standard thickness blade that is split down the length, with a replaceable edge insert.

It's on sale here in a couple of places, and according to a neighbor who works at a retail outfit that sells it, the price ($50., +/-) is keeping sales pretty low, primarily due to the fact that you have to spend around $10.-$15. for a pack of four replacement blades. I'd imagine that the cost to keep tolerances where they need to be to make it reliable aren't going to allow for an inexpensive product. My neighbor says most people just go for a regular Stanley utility knife.

thx - cpr
 
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Too brittle for knife blades, but they make cool wedding bands! :D

My ring is mirror pollished tungsten carbide. Been wearing it for a few years now and nothing has been able to put even the slightest scratch in it so far!

-That's pretty hard stuff! And quite heavy too for its size.
 
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