Faux Anodized Aluminum Effect
My standard "must get this look" finishing advice - prepare several scrap pieces exactly as you have prepared the primed wood, and test the entire finish process on them. Practice makes perfect, and practicing on the final object makes a mess out of it.

My gut guess (and it's a guess, not experience in creating your precise finish) depending on exactly what sort of black aluminum finish appearance you seek would be to undercoat with aluminum paint or light gray primer, and then spray with "transparent black" (or paint with a clear finish with a compatible black dye mixed in.) If trying to match a brushed aluminum look, some texturing of the base coat might help. Steel wool or non-woven abrasive pad after the finish has hardened might help get the surface/shine right.