AMS 2488 Titanium Anodizing, Type I & II
SAE ASM 2488D Titanium Anodizing, Types 1 & 2, will be briefly reviewed in this article.
All titanium anodize coatings are not the same. Anodizing titanium to achieve colors is different than anodizing titanium to achieve mechanical characteristics. The medical device and jewelry industries make use of color titanium anodizing for product identification and aesthetic purposes. The aerospace, military and machine tooling industries make use of titanium anodizing for imparting surface improvements to titanium alloys. These improvements include anti-galling, wear resistance and improved corrosion resistance.
AMS 2488D is the controlling specification for industrial titanium anodizing. SAE International (The Engineering Society for Advancing Mobility Land Sea Air and Space) is the governing authority for AMS 2488 which was first issued in July of 1977 and last revised in June of 2000 as SAE AMS 2488D.
AMS 2488 Specifies two classes of titanium anodizing – Type I and Type II
Type I Titanium Anodizing per AMS 2488 is to be used…
- “As a coating for elevated temperature forming.” Because Type I is so specialized we will concentrate on Type II titanium anodizing for the remainder of this article.
Type II Titanium Anodizing per AMS 2488D is to be used…
- “As an anti-galling application without additional lubrication or as a pretreatment for improving adherence of film lubricants where increased resistance to galvanic corrosion is required…”
How does AMS 2488 Type II Titanium Anodizing differ from color anodizing?
- Type II anodizing is not multi-colored – the surface becomes a dark grey after anodizing.
- Type II anodizing must be processed in an electrolyte that has a pH greater than 13.
- Type II operating parameters are generally more stringent than color anodizing.
- Type II anodizing is complete when the amperage drops off to zero.
- Halogenated solvents are not permitted as cleaning agents with Type II – Check out http://anodizetitanium.com/category/titanium-anodizing-tips-and-tricks/ for cleaning tips.
- Type II Anodizing may leave a powdery residue which must be mechanically removed.
- Protocols for surface testing and QA are significantly different than color anodizing.
The parts on the left have not had any anodizing done, but the parts on the right were anodized and are shown prior to sandblasting to remove that powdery residue. For more on AMS 2488 Type II Titanium Anodizing, see our article here.
AMS 2488 Titanium Anodizing
There are applications used by the medical device industry where Type II-like titanium anodizing is used for the impregnation of film lubricants to improve bio-compatibility. However these processes are not reviewed in this article.
AMS 2488 Titanium Anodizing is not the same as conventional color anodizing. AMS 2488 is an industrial and not a decorative coating. Aluminum anodizing to Mil-A-8625 Type II is not the same as Titanium anodizing. For more information about Aluminum Anodizing vist www.anodizingequipment.com
To sum it up… When titanium anodizing is used by the medical device industry for aesthetics and/or product identification, AMS 2488 may not be applicable.