Gold Plating

[vona0018]

I have a highly technical question. I am gold plating to prevent hydrogen permeation and I am getting different shades of gold. I believe this is because of different surface roughnesses causing different refraction of light. My question is if anyone knows if this can hinder the prevention of hydrogen permeation or if anyone knows another reason why the I am getting different shades?

Thanks

[engineerscott]

One would suspect that a rougher finish would present more surface area. Since the rate of permeation is a function of surface area (and temperature, partial pressure of H2, etc., etc.) then you would expect that as the roughness goes up, the surface area goes up, and the rate of permeation goes up. Therefore a smoother surface should give you lower permeation rates.

[vona0018]

Now is it not true that I am using gold plating because of its lattice structure, having gaps smaller than the hydrogen atoms. So the surface area should not matter because the gold will prevent H+ from getting through or does gold just stop most H+ atoms.

Thanks