Black steel

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kaizo

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Oct 17, 2014
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I see a lot of black coating on knives but has there ever been attempts to dope the steel itself to give it an inherent black colour to the steel itself?

It just popped into my mind when I was handling a boron doped diamond sample in my lab today. Depending on the concentration, boron can give clear diamond a near black blue colour so I thought some form of impurities could potentially cause colour change to the steel...
 
Like black oxide? Also known as bluing.

But that is just a surface transformation. Specific to your question, I have a hard time seeing any opaque, dense crystal lattice like iron take on some much of an impurity that it would stop being a shiny metal color when you grind into it. I imagine the levels of impurities that it takes to get clear crystals like diamond, sapphire and glass to become colored and nearly opaque are very small, because they let light through in the first place.
 
Hi thanks for your reply. Yeah translucent crystals doesn't take much to colour in fact most natural diamonds are yellow due to trace amounts of nitrogen. I suppose the only real way to get around it is if you make the entire blade out of carbon. I've seen one on the Busse forum but apparently they are illegal because they are concealable.

Yalius thanks for the link. If someone did do that they have the added bonus of an easy to clean blade!!

That treatment seems to rely on a micro/nano surface structure so as you suspected it probably will be shiny under its epidermis...

I start to understand why people just paint coating over.
 
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kaizo said:
Hi thanks for your reply. Yeah translucent crystals doesn't take much to colour in fact most natural diamonds are yellow due to trace amounts of nitrogen. I suppose the only real way to get around it is if you make the entire blade out of carbon. I've seen one on the Busse forum but apparently they are illegal because they are concealable.
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Illegal? You can make a knife out of anything, legally. Ceramic knives are very common and don't register on metal detectors. Glass knives are also legal.

I can't think of a carbon structure that would make a good blade, short of some sort of Fullerene.
 
RX-79G said:
Illegal? You can make a knife out of anything, legally. Ceramic knives are very common and don't register on metal detectors. Glass knives are also legal.

I can't think of a carbon structure that would make a good blade, short of some sort of Fullerene.
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Thanks for correcting me. :) Sorry I'm not familiar with knife laws so I took what I read for what it is.

EDIT: I looked for the post but I couldn't find it so I might have been mistaken all together... Sorry lads.

The carbon knife is called the stealth hawk:

http://www.bladeforums.com/forums/s...ex-Bogdog-Stealth-Hawk?highlight=stealth+hawk

It hasn't really stepped outside of the lab and specialised use yet but carbon allotrope like diamond and carbon nanotube has show quite a bit of promise. Diamond is more popular as coatings for diamond cutters etc... but making a knife size diamond is not too technically challenging. A solid piece of diamond the size of an open hand used for the tomahawk missile's nose cone that my boss usually pulls out for his students every now and then costs about £12,000 (so about $18000) so I think its more about the cost at the moment. Carbon nanotubes are probably best attempted by making composites out of them then sharpening. Once a few details has been ironed out I think they will make fantastic handle materials (potentially even better than G10).
 
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If you want a material that's a dark color all the way through and won't get "shiny" when abraded, your best bet is probably some sort of ceramic or polymer.
 
RX-79G said:
Nanotube=Fullerene
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Ah so when you said some form fullerene you were referring to all forms of sp2 carbon, got it (sorry I thought you were talking about carbon onions which is multi layered fullerene). Fullerene/carbon onion is spherical so its doesn't really have a notable reinforcement effect that carbon nanotubes has so I didn't pick up on it. I hope I didn't offend you.

Thanks for your reply again.
 
asdf12345 said:
If you want a material that's a dark color all the way through and won't get "shiny" when abraded, your best bet is probably some sort of ceramic or polymer.
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Thanks for your reply :)

Yeah I was just curious but from the sounds of it ceramic is probably the closest candidate.
 
kaizo said:
Ah so when you said some form fullerene you were referring to all forms of sp2 carbon, got it (sorry I thought you were talking about carbon onions which is multi layered fullerene). Fullerene/carbon onion is spherical so its doesn't really have a notable reinforcement effect that carbon nanotubes has so I didn't pick up on it. I hope I didn't offend you.

Thanks for your reply again.
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None taken. I had been given to believe that nanotubes where just another arrangement of Fullerene. If my usage was incorrect, my apologies.
 
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