Titanium is a wonderful metal, with the highest strength to density ratio of all metals. This lightweight strength is what makes it so perfect for spacecraft, aircraft, and of course, knives.
Why are anodized titanium treatments done?
With anodized titanium treatments, the metal becomes an artistic canvas for the metalsmith. This treatment permanently colorizes the metal without the need to apply a coating or plating. It provides a wide variety of colors from which to choose, including yellow, green, pink, gold and blue.
How does it work?
Anodizing takes advantage of the oxidizing properties of titanium. When the surface of titanium is exposed to electricity or heat it forms a thin, oxidized layer. This layer has prismatic, color-changing properties similar to that of a soap bubble. The color of the layer varies according to its thickness.
Two types of anodizing - Here's a look a two processes that really make the metal have a beautiful finish:
This method works well for producing a single, evenly-toned color. The treatment uses direct current of at least 80 volts and between 1 and 3 amps. The titanium piece hangs in a bath of conductive liquid connected to a power source by a strip of conductive metal. Current is applied to the metal until it changes to the desired color. The color varies according to the amount of amperage and voltage being used.
Since titanium is reactive, a thin layer forms on the surface of the metal. Even though this layer is translucent, it looks like different colors because of how it refracts light. This electric method creates a very uniform color change across the surface, and you can cover areas you don't want to change to create patterns.
The reaction is identical, but the reaction is triggered by heat instead of electrical current. Heat anodizing is less precise than the electrical method, but it can produce more complex results, such as gradients or multicolored effects. However, this is more useful for creating swirls or rainbow patterns. The first step is to completely clean and dry the piece, then a flame is applied directly to the metal until it changes color. Any dust or fingerprints will leave imperfections in the coloring. The color can be changed at specific spots by bringing a hotter flame in closer.
Are there any drawbacks?
Anodized surfaces can scratch during everyday carry when contacting other objects, and the color may be altered by contact with skin oil. Also, heat-anodized titanium may be more vulnerable to wear than electrically-anodized titanium. However, anodizing actually increases the resistance of titanium to corrosion and wear, and the oxidized layer can hide scratches.
All-in-all, titanium anodizing treatments can be regarded as a way of enhancing the quality and beauty of knives.