I have two parts that are matched to each other. One has a key and the other the matched keyway. The key and the keyway will have some abrasions against each other due to vibrations. I can use steel for these two parts, but it cost me too much weight. I would like to use aluminum in combination with some hardening to improve its abrasion resistance. A conventional way to improve hardness is anodizing. A more aggressive way is coating with Nikasil, a method used in engine cylinder wall hardening (I remember someone once told me Rotax 912 also used this).
Any comment/ critique/ personal experience/ watch-outs/ alternative method?