Dave and Rudy, It is important to remember that brown oxide by virtue of it's shorter and much more densely packed crystal strucure has a much greater surface area than black oxide. Thisprovides the pepreg with many more bonding sites with which to grab on to thus improving the bond strengths. Also I have performed a number of test on the composition of brown and black oxide coatings. I found that black oxide contains a much greater proportion of thermally unstable cuprous oxide than does the brown. During the lamination cycle, the cuprous oxide can decompose forming oxygen, thus contributing to delamination. Good luck