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Optical black

There is a die-casting aluminium,which was used in a projection television as a CRT coupler. In the inner wall, it is optical black to reduce the reflection coefficient, especially specular reflection. There is filled with cooling liquid in CRT coupler, eg,glycol and so on,which refraction coefficient is 1.4-1.5. The common way to treat the CRT surface is anode oxidation and coating organic coat. I wonder if the way finishes the CRT is available, in which the order is: First, chemical anode oxidation, then coat black paint, last,coat resin?

Claudia Luo
- Chengdu, Sichuan Province, China

My be better to treat with a chromate conversion coating and put your organic coating on the top. Anodizing (Chemical anode oxidation) is not very suitable for a die-cast aluminum part.

S. Y. Yuen
- Hong Kong, China

The purpose of anodizing in your application is mainly to enhance paint adhesion. If you do not like anodizing, chemical conversion coating or phosphating can be employed to replace anodizing. Phosphating and chromating both are just chemical immersion processes. Pretreatment is same.

Ling Hao
- Grand Rapids, Michigan

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