plating, anodizing, & finishing Q&As since 1989
7075-T6 Anodising Poor Appearance
Q. Hi there.
I have a question about anodising 7075-T6, we machine a lot of parts and have excellent results with certain mills that produce the material.
Some other mills material seems to produce a much more dull and pitted appearance.
I'm sure its down to the chemical make up of the bar.
Of the 2 bars below one anodises very very well and the other does not.
Looking at the chemical makeup any idea why one of the bars does not??
Bar1 0.09 0.15 1.30 0.06 2.30 0.19 5.6 0.04
Bar2 0.14 0.10 1.51 0.03 2.35 0.20 5.6 0.03
- United Kingdom
June 16, 2022
A. It's probably not the composition. Both analyzes are normal. The microstructure and e.g. the purity of the melt (e.g. oxides, impurities) have a major influence. Would also compare the strength, hardness and electrical conductance.
Pictures of the anodized surfaces would also be helpful.
- Hallau, Switzerland
June 24, 2022
A. Heat from either heat treatment or dull machining can move the zinc to the surface and affect the anodic film.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina