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Is it true that Titanium does not rust?
- Thread starter drjones
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It is true.
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Nope, Ti is virtually indestructible.
Gollnick
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Sure, Ti can rust. Rust is properly called "oxidation."
When Iron reacts with Oxygen, it forms Iron Oxide which is a redish to grey-blackish flakey powdery substance. That's what we normally think of as rust. This reaction is slow.
When Aluminum reacts with Oxygen, it forms Aluminum Oxide which is a crystal-clear substance that is in the same league as diamond for hardness. Aluminum Oxide is commonly used as an industrial abrasive. This reaction is very, very fast. Virtually every piece of aluminum you've ever seen has been completely covered with rust. But, because it's clear, you don't see it. And because it's so tough, it actually self-limits. After a layer only a few molecules thick forms on the surface, no more oxygen can get in and the reaction stops. So, the reason Aluminum is commonly thought of as rust-proof is that it's already covered in rust.
When Titanium reacts with Oxygen, if forms Titanium Oxide which is a powdery white substance that's fairly soft (on the same order as chalk). 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. The oxidation of Titanium at room temperature proceeds at almost glacial rates. So, your Ti liner will rust, yes, sorry, but not in your lifetime or that of your children or grand children or great-great grandchildren or...
Off hand, I can not think of any metal that truly does not rust at all.
When Iron reacts with Oxygen, it forms Iron Oxide which is a redish to grey-blackish flakey powdery substance. That's what we normally think of as rust. This reaction is slow.
When Aluminum reacts with Oxygen, it forms Aluminum Oxide which is a crystal-clear substance that is in the same league as diamond for hardness. Aluminum Oxide is commonly used as an industrial abrasive. This reaction is very, very fast. Virtually every piece of aluminum you've ever seen has been completely covered with rust. But, because it's clear, you don't see it. And because it's so tough, it actually self-limits. After a layer only a few molecules thick forms on the surface, no more oxygen can get in and the reaction stops. So, the reason Aluminum is commonly thought of as rust-proof is that it's already covered in rust.
When Titanium reacts with Oxygen, if forms Titanium Oxide which is a powdery white substance that's fairly soft (on the same order as chalk). 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. The oxidation of Titanium at room temperature proceeds at almost glacial rates. So, your Ti liner will rust, yes, sorry, but not in your lifetime or that of your children or grand children or great-great grandchildren or...
Off hand, I can not think of any metal that truly does not rust at all.
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Hmmm...must have been thinking of salt water
The closest that you'll come to a truly non-rusting metal is Gold.
While Auric Oxide (gold rust) can be created in the laboratory, it is never found in nature.
In order to make it you have to go through a complicated reaction involving several steps and many different chemicals. The resulting gold rust is inherently unstable and will readily decompose back into gold metal and oxygen gas.
So while you can indeed force gold to react with oxygen under certain odd conditions, it is naturally inclined to not rust and won't do so without some help from chemists. I suppose that depending on how you look at things it could be considered a non-oxidizing metal.
You can find some more details here.
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You know for all the wonderful properties of Titanium, rust proof, wear resistant, and strength, why is it when I used a Buck Titanium Folder to hold a pistol target to a piece of plywood, I shot, missed the target, and a brass BB from my air pistol left a perfectly round dent in the end of the scale. This run on sentence brought to you by Brother Regis, of the Brothers of the Sacred Heart.
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Because Titanium aint the hardest stuff in the world... and I doubt it's an especially strong alloy or especially well-temepered at the low price Buck was asking for it.
High-velocity copper smacks soft material, bad for copper, bad for titanium.
Sorry, it's just physics.
High-velocity copper smacks soft material, bad for copper, bad for titanium.
Sorry, it's just physics.
Actually...
The above posts are correct, but not the whole story.
Iron rust (iron oxide) take up a larger volume than the iron from which it reacted, which causes it to flake off. This exposes more iron, which continues to oxidize.
Titanium is an extremely reactive metal. Finely divided (powder) and exposed to air, it may under some circumstances self ignite because the reaction is so fast and the heat of reaction is high. Fortunately, titanium forms a very tenacious oxide layer (as noted above) which impedes the transfer of oxygen to the pure titanium below the oxide layer. The oxide does not flake off. This makes titanium resistant to corrosion in most environments, and it is why it is used in chemical plants in many instances where stainless steel corrodes too quickly. And in sea water. But in environments where there is no oxygen present (and I mean parts per million) titanium can corrode very quickly, since the oxide layer dissolves off, and the rapid reaction with titanium metal proceeds unimpeded. This does not happen except with certain chemicals. I have seen chemical process equipment fail very rapidly because titanimum was specified, but the designers overlooked this last detail about the oxygen requirement.
Stainless steel works by the same principle, as does aluminum. The oxide layer (chromium oxide and aluminum oxide) prevents oxygen from penetrating to the pure metal below.
Sorry to bore you...
The above posts are correct, but not the whole story.
Iron rust (iron oxide) take up a larger volume than the iron from which it reacted, which causes it to flake off. This exposes more iron, which continues to oxidize.
Titanium is an extremely reactive metal. Finely divided (powder) and exposed to air, it may under some circumstances self ignite because the reaction is so fast and the heat of reaction is high. Fortunately, titanium forms a very tenacious oxide layer (as noted above) which impedes the transfer of oxygen to the pure titanium below the oxide layer. The oxide does not flake off. This makes titanium resistant to corrosion in most environments, and it is why it is used in chemical plants in many instances where stainless steel corrodes too quickly. And in sea water. But in environments where there is no oxygen present (and I mean parts per million) titanium can corrode very quickly, since the oxide layer dissolves off, and the rapid reaction with titanium metal proceeds unimpeded. This does not happen except with certain chemicals. I have seen chemical process equipment fail very rapidly because titanimum was specified, but the designers overlooked this last detail about the oxygen requirement.
Stainless steel works by the same principle, as does aluminum. The oxide layer (chromium oxide and aluminum oxide) prevents oxygen from penetrating to the pure metal below.
Sorry to bore you...
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Hey I take offense to that, when I was on the rifle team back in 74' we were East Coast Regional Champs, till that bunny hopped onto the range Danny hit it with the first shot than all hell broke loose, 15 shots later that bunny was still in the air, the last words I remember hearin' was the Rangemaster screamin'"Cease fire, cease fire, rifles down, rifles down" When he walked in front of us holding that perforated bunny, he was pissed
. Needless to say we were all thrown off the team, and barred from the range forever.
I hit my target then, too bad my target wasn't the bunny. Poor bunny he didn't deserve to die like that.
I carried a Schrade 51OT back then.
Danny hit it with the first shot than all hell broke loose, 15 shots later that bunny was still in the air, the last words I remember hearin' was the Rangemaster screamin'"Cease fire, cease fire, rifles down, rifles down" When he walked in front of us holding that perforated bunny, he was pissed. Needless to say we were all thrown off the team, and barred from the range forever. I hit my target then, too bad my target wasn't the bunny.
Poor bunny he didn't deserve to die like that. I carried a Schrade 51OT back then.
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Sorry, I don't have anything worthwhile that hasn't been mentioned before to contribute to this discussion, but I just wanted to say thanks to Gollnick and fishbulb. Most interesting posts, guys!
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One of titaniums greatest properties is corrosion resistance ( except in Don Ms oxygen free world).It will not be bothered by water or salt water or anything else you might encouter. They do make titanium bladed dive knives.It weighs half as much as steel.Heat treated alloys can be very strong .Check out camillus dominator and reeve sebenza.
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2nd'ed. awesome stuff
the education is much appreciated!
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Ok, what about Talonite and Stellite? And besides that, whats the differences between them?
Titanium works by forming a passive oxide layer. You're best to leave it alone, or use hot nitric acid on it
I don't believe it works well in caustic though, not that you'd likely encounter that. I'm a chemical Engineer and I've worked in Pulp Mills where corrosion is incredible. I've seen huge stainless steel bolts riddled with holes from chlorine pitting such that it looked like swiss cheese. Titanium does work quite well in nasty corrosive chemicals (acid chlorides).
I don't believe it works well in caustic though, not that you'd likely encounter that. I'm a chemical Engineer and I've worked in Pulp Mills where corrosion is incredible. I've seen huge stainless steel bolts riddled with holes from chlorine pitting such that it looked like swiss cheese. Titanium does work quite well in nasty corrosive chemicals (acid chlorides).