Titanium anodizing is an electrolytic finishing process that manipulates the oxide layer on the surface of titanium via electric current. The titanium item forms the anode (positive electrode) of an electrolytic cell; hence the name “anodize.”
Titanium anodization is commonly used in aerospace and orthopaedic implants.
So, How to Anodize Titanium?
Here is an example of process steps:
1. Strong alkaline cleaner—As in all metal finishing a through cleaning must be accomplished, preferably in a strong alkaline cleaner, at 140-160 degrees Fahrenheit for a water break free surface. Electro-cleaning may be desirable but not required. 5-10 minutes.
2. Cold Rinse — Ensure any alkaline detergents are removed from the part.
3.Acid etch/activate in 20-50% nitric acid 1-3 minutes. For a more even surface the addition of fluoride is advisable.
4.Anodize at 10 ASF and 10-75 volts depending on final color desired. Color will vary with voltage and time from golden brown at 10 Volts / 20 min to blue at 75 Volts / 12 min.
Types of titanium anodizing
There are two commonly used types of titanium anodizing: Type 2 and Type 3. Type 1 is far less common, and is used in specialized high-temperature treatments.
Type 2 Anodized Titanium helps patients with orthopedic implants by improving mobility of joints, and compatible with aircraft fluids and can withstand extreme temperatures within a range of -70 °F to 260 °F.
Type 3 Anodized Titanium also used in medical device and aerospace industries, Type 3 colored titanium finishes are also used in jewelry manufacturing.