Is it true that Titanium does not rust?

strictly speaking, only iron 'rusts'
rust is what we commonly call hydrated iron oxide
other metals oxidise
but most of these oxides don't flake off and expose more of the metal
for example, aluminum oxide forms a layer impermeable to oxygen on the surface of the metal itself, preventing further oxidation
 
why dont we worry more about dissimilar metals being in contact with each other in the construction of the Knife?

Are makers careful to eliminate this problem with careful use of things like plastic bushings and washers? i always worried about haveing other metals in contact with the blade of my knives since it seems like a corrosion hazard.

I dont remember much chemistry, but if i have a Ti and Steel Plate in contact is corrosion more likely to occur? How about other materials?
 
If two different metals are in contact there can be noticeable corrosion IF the environment is corrosive. The less noble one metal will corrode preferentially. However, most environments to which knives are exposed are mild enough that the corrosion rate is very low to begin with, so it really doesn't matter. This is a big issue in the chemical industry, but not in the knife industry. Sea water may be an exception to this, if you have a dive knife, you probably want to stay away from knives that have different metals in contact.
 
Stellite and Talonite are essentially the same, Stellite is no longer available. They are not steel but cobalt alloys. As far as I know the corrosion resistance is good.--- As far as galvanic corrosion ( corrosion between two dissimilar metals ) it requires a coductive liquid like salt water.
 
Galvanic action does occur, with or without a medium, as does electrolysis, but at vastly different rates depending mostly on the metals involved. One of 'em is gonna give up the electrons, baby. Put a piece of copper near a piece of steel, get out your loupe, and watch them 'trons play. But, for our purposes, they got the metals figured out pretty good.
 
Depends on the knife, but the higher quality titanium knives (liners and/or frames) tend to be made of 6AL-4V.

As for stuff like Mission knives... they use their own special alloys for their blades
 
Oooh! and here's a fun question we can inject. Does anodizing Titanium (or even aluminum) prevent them from generating their respective oxides?
 
uhm
the anodic process that result in anodising of the metal surface is actually oxidation
ie, anodised aluminum is aluminum oxide
 
I've read that ferric rust (iron or steel) feeds off itself and will keep growing if left to itself. Oxidation on aluminum, however, will stop itself after it forms. Not sure if that applies to Ti as well.

Ash
 
Originally posted by Grover_Cephas
Tell it to Tutankhamen ;)
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Speaking of buried treasure...

Ever notice that when those salvage divers find the wreck of some ancient galleon and start hauling the artifacts up only the gold is in good shape?

After a few hundred years silver coins will be heavily corroded and the iron cannons will be a solid mass of rust and seaweed, but the gold still looks like it's brand new. You could put it back in the ocean and come back in a thousand years and it would still look the same. It simply doesn't react except under the most extreme conditions.

Gold has a lot of unique properties, really a fascinating material.

It's a shame that there isn't more gold around here (meaning Earth) as all those unique properties would make it incredibly useful to the electronics and manufacturing industries if it wasn't so expensive.
 
Originally posted by fishbulb
Speaking of buried treasure...

Ever notice that when those salvage divers find the wreck of some ancient galleon and start hauling the artifacts up only the gold is in good shape?

...the gold still looks like it's brand new. You could put it back in the ocean and come back in a thousand years and it would still look the same. It simply doesn't react except under the most extreme conditions.
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But it can be "encrusted" with all kinds of crap.

There was a li'l furor in the numismatic community a few years back when the Professional Coin Grading Service (they "slab" coins in hard plastic holders with a paper tag identifying the coin and its "official" condition, graded on a scale of 1-100) removed surface deposits from gold coins recovered from the wreck of the SS Central America, then graded them as if they hadn't been cleaned. It sparked a bit of a debate (and a healthy one, IMHO) regarding the practice of "cleaning" coins, and the effect it should have on their value.
 
After a few hundred years silver coins will be heavily corroded and the iron cannons will be a solid mass of rust and seaweed, but the gold still looks like it's brand new.
Click to expand...

I recently saw an exhibit of artifacts for the Titanic. I was surprised at how well-preserved the iron and steel stuff was. The guide noted that as you go down deeper in the ocean, the concentration of oxygen in the water goes down. So, metal does not oxidize or rust as quickly in deep water.
 
It sparked a bit of a debate (and a healthy one, IMHO) regarding the practice of "cleaning" coins, and the effect it should have on their value.
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And what, pray tell, was the conclusion?

There are, of course, a very analogous situations with knives. I've always maintained that it's ok to gently remove surface dirt but that you should never rub or scrub or polish.
 
Originally posted by LizardKing
why dont we worry more about dissimilar metals being in contact with each other in the construction of the Knife?
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I don't know about "corrosive environment" but as a collector of vintage bicycles, I know that an aluminum handlebar stem or seatpost, in any kind of environment, can produce some sort of chemical reaction that can make it *nearly* impossible to remove from the steel bicycle frame.
 
Originally posted by Gollnick
Titanium Oxide is very, very bright white. In fact, it's a common pigment in white paint. It's also common in cosmetics, especially powders where it lightens the color, gives a bit of a "sparkle" appearance that people associate with purity and cleanliness, and also helps keep the powder from caking and clumping.
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Chuck,
I think you are thinking of TiO2, titanium dioxide.
I don't know whether that's the same oxide that would form in air at room temperature.
 
Originally posted by fishbulb
Speaking of buried treasure...

Ever notice that when those salvage divers find the wreck of some ancient galleon and start hauling the artifacts up only the gold is in good shape?

After a few hundred years silver coins will be heavily corroded and the iron cannons will be a solid mass of rust and seaweed, but the gold still looks like it's brand new. You could put it back in the ocean and come back in a thousand years and it would still look the same. It simply doesn't react except under the most extreme conditions.

Gold has a lot of unique properties, really a fascinating material.

It's a shame that there isn't more gold around here (meaning Earth) as all those unique properties would make it incredibly useful to the electronics and manufacturing industries if it wasn't so expensive.
Click to expand...

I sit next to a guy at work who used to work as a chemist somewhere, so he occasionally discusses stuff about topics like this. I asked him once about gold's anti-reactive properties, and we got to talking about PLATINUM, which he described as "way better than gold" for the purposes of corrosion-resistance we're talking about. The info posted here in this thread has been fascinating to me. Can anyone tell us more about platinum?
---Jeffrey
 
Originally posted by Gollnick
And what, pray tell, was the conclusion?

There are, of course, a very analogous situations with knives. I've always maintained that it's ok to gently remove surface dirt but that you should never rub or scrub or polish.
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Predictably, there was never any unanimous "conclusion" to speak of. The investors in the excavation sold off all of the "controversial" coins with no trouble at all, PCGS continued to occasionally slab "curated" gold coins (particularly those from antiquity) at full grades. PCGS (and a few other "slabbing" services) is so useful in an increasingly on-line market that even as conservative collectors _continue_ to complain about their policies, the numismatic community pretty much just deals with it. There's generally an "it sucks, but whaddayagonnado?" attitude.

Personally, I think the objecting collectors lost sight of the _point_. The reason coin cleaning was looked down on originally was that it could damage the coins (same deal as with knives--abrasives kill the finish and non-abrasives can remove the patina). When the cleaning process is completely nondestructive, who loses?

...Okay, so the "losers" were those who'd had their own cleaned coins rejected by PCGS, and those who'd let "no cleaning" become a tenet of numismatic orthodoxy rather than a means to an end, but whaddayagonnado? ;)
 
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