The Unified-PC comes in Utilitarian Aluminum, which is a stock aluminum with some of the original scratches and scuffs. We clean it up, debur it, and do some polishing to produce a more uniform look and to protect the surface. This aluminum alloy is designed to resist corrosion. We also add a special sealant that further resists corrosion, reduces the chances of chipping, and without negatively impacting thermal conductivity, convection and emmissivity properties.
We intentionally leave some scratches to go along with the utilitarian theme. These are further protected by the sealant.
However, you may choose to have your unit fully polished instead (see drop-down menu for surface treatments below).
Powder coating (a high-tech surfacing that's tougher than paint) is available in matte black. In most scenarios the pros and cons of thermal properties between powder coating and bare aluminum roughly cancel out, making this a subjective decision. However, powder coating switches heat elimination from primarily convection to primarily radiation, which is a good idea when the PC is operated in a bad air environment (such as a closet where air flow is bad, to instead radiate the heat into the floor, ceiling and walls). However, if you plan to use the PC in front of a direct source of radiant heat (such as the sun, or a fire place) then it is better to go with bare aluminum, to reflect outside heat away while convecting away its own heat.