Solderability of a metal

I have a project to evaluate solderability of various metals or plated finish. I'd like to tap in to get some advise. The project is to evaluate solderability of various metals or plated finishes for RF shield application with reflow. Due to the high corrosion resistance, Cu-Ni alloy is in consideration. There are multiple ways to test solderability. It seems there is no definitive value to determine the acceptable level in the industry. I guess I�ll have to run some comparative study with know material such as tin plated. What would you recommend for the best practice or comparison?

1. Dip and look 2. Print paste and solder spread after Reflow 3. Wetting force balance 4. wetting angle

Secondly, I suspect Cu baring metal would tarnish over time and it provides corrosion resistance. At the same time, it also works against solderability. Therefore, I expect the solderability would deteriorate over time as tarnish builds up on the surface. I wonder if need to consider this and if so is there a way to accelerate aging for this evaluation? I�m thinking about temperature oven and moisture if that makes sense.

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