Titanium has a "self-healing" protective coating?
01-17-12 | 09:25 AM
#1
Thread Starter
Just Plain Slow
Joined: Mar 2010
Posts: 6,026
Likes: 5
From: Santa Clarita, CA
Bikes: Lynskey R230
Titanium has a "self-healing" protective coating?
This is what happens when I'm getting my treatments....I have time to obsess and find useless info. However, I found this interesting. Now, I found it on the internets, so even though I don't know for certain the source is 100% reliable, it must be true! From https://www.timet.com/cor-p04.htm
Titanium and its alloys provide excellent resistance to general localized attack under most oxidizing, neutral and inhibited reducing conditions. They also remain passive under mildly reducing conditions, although they may be attacked by strongly reducing or complexing media.
Titanium metal's corrosion resistance is due to a stable, protective, strongly adherent oxide film. This film forms instantly when a fresh surface is exposed to air or moisture. According to Andreeva^(1) the oxide film formed on titanium at room temperature immediately after a clean surface is exposed to air is 12-16 Angstroms thick. After 70 days it is about 50 Angstroms. It continues to grow slowly reaching a thickness of 80-90 Angstroms in 545 days and 250 Angstroms in four years. The film growth is accelerated under strongly oxidizing conditions, such as heating in air, anodic polarization in an electrolyte or exposure to oxidizing agents such as HNO3, C(R)O3, etc.
The composition of this film varies from TiO2 at the surface to Ti2O3, to TiO at the metal interface^(2). Oxidizing conditions promote the formation of TiO2 so that in such environments the film is primarily TiO2. This film is transparent in its normal thin configuration and not detectable by visual means.
A study of the corrosion resistance of titanium is basically a study of the properties of the oxide film. The oxide film on titanium is very stable and is only attacked by a few substances, most notably, hydrofluoric acid. Titanium is capable of healing this film almost instantly in any environment where a trace of moisture or oxygen is present because of its strong affinity for oxygen.
Anhydrous conditions in the absence of a source of oxygen should be avoided since the protective film may not be regenerated if damaged.
Titanium metal's corrosion resistance is due to a stable, protective, strongly adherent oxide film. This film forms instantly when a fresh surface is exposed to air or moisture. According to Andreeva^(1) the oxide film formed on titanium at room temperature immediately after a clean surface is exposed to air is 12-16 Angstroms thick. After 70 days it is about 50 Angstroms. It continues to grow slowly reaching a thickness of 80-90 Angstroms in 545 days and 250 Angstroms in four years. The film growth is accelerated under strongly oxidizing conditions, such as heating in air, anodic polarization in an electrolyte or exposure to oxidizing agents such as HNO3, C(R)O3, etc.
The composition of this film varies from TiO2 at the surface to Ti2O3, to TiO at the metal interface^(2). Oxidizing conditions promote the formation of TiO2 so that in such environments the film is primarily TiO2. This film is transparent in its normal thin configuration and not detectable by visual means.
A study of the corrosion resistance of titanium is basically a study of the properties of the oxide film. The oxide film on titanium is very stable and is only attacked by a few substances, most notably, hydrofluoric acid. Titanium is capable of healing this film almost instantly in any environment where a trace of moisture or oxygen is present because of its strong affinity for oxygen.
Anhydrous conditions in the absence of a source of oxygen should be avoided since the protective film may not be regenerated if damaged.
01-17-12 | 09:27 AM
#2
Senior Member
Joined: Jun 2007
Posts: 12,257
Likes: 5
From: A Coffin Called Earth. or Toronto, ON
Bikes: Bianchi, Miyata, Dahon, Rossin
you figured this out now?
aluminum has the same thing, btw.
aluminum has the same thing, btw.
__________________
Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
01-17-12 | 10:07 AM
#5
Should Be More Popular
Joined: Dec 2007
Posts: 46,337
Likes: 11,829
From: Malvern, PA (20 miles West of Philly)
Bikes: 1986 Alpine (steel road bike), 2009 Ti Habenero, 2013 Specialized Roubaix
01-17-12 | 10:15 AM
#7
Senior Member
Joined: Jan 2011
Posts: 1,153
Likes: 0
01-17-12 | 10:35 AM
#10
Descends like a rock
Joined: Oct 2010
Posts: 4,034
Likes: 16
From: Fort Worth, TX
Bikes: Scott Foil, Surly Pacer
yes, the difference is that rust will continue to pit into the material, but with Ti and Al, the oxidation layer seals off the inner material and prevents further oxidation from continuing.
01-17-12 | 10:39 AM
#11
Senior Member
Joined: Jan 2011
Posts: 1,153
Likes: 0
so correct me if i'm wrong but it sounds like you're saying steel is the worst possible material in existence to use as a bicycle frame material?
01-17-12 | 10:41 AM
#12
Senior Member
Joined: Aug 2009
Posts: 4,144
Likes: 3
From: Burnaby, BC
01-17-12 | 10:42 AM
#13
Descends like a rock
Joined: Oct 2010
Posts: 4,034
Likes: 16
From: Fort Worth, TX
Bikes: Scott Foil, Surly Pacer
yes unpainted non-stainless steel, left out in rain frequently and not cared for is a terrible material for bikes. (kind of like non-clear coated carbon)
On the other hand, I'm currently restoring my mom's old early 1950's model cruiser - it has some rust, but it sands right off to clean metal with a little sand paper. Another 60 years or so, and thing would have been toast though.
On the other hand, I'm currently restoring my mom's old early 1950's model cruiser - it has some rust, but it sands right off to clean metal with a little sand paper. Another 60 years or so, and thing would have been toast though.
01-17-12 | 10:58 AM
#16
Senior Member
Joined: Sep 2007
Posts: 15,336
Likes: 1,788
From: Far beyond the pale horizon.
As you realize.
01-17-12 | 11:06 AM
#18
Descends like a rock
Joined: Oct 2010
Posts: 4,034
Likes: 16
From: Fort Worth, TX
Bikes: Scott Foil, Surly Pacer
01-17-12 | 11:23 AM
#19
Reasonably Slow...
Joined: Nov 2010
Posts: 628
Likes: 1
From: Middle of Oklahoma
01-17-12 | 12:27 PM
#22
Senior Member
Joined: Sep 2007
Posts: 15,336
Likes: 1,788
From: Far beyond the pale horizon.
Last edited by njkayaker; 01-17-12 at 12:32 PM.
01-17-12 | 12:41 PM
#24
Speechless
Joined: Jun 2011
Posts: 8,842
Likes: 39
From: Central NY
Bikes: Felt Brougham, Lotus Prestige, Cinelli Xperience,
From afar, this thread appears to have peaked at "ti-curious" before devolving to "drivel". Very sad. Perhaps some intervals between the two might refresh the mitochondria, or just turn you all into hypo-mitochondriacs.
Just sayin
Just sayin
