On Thu, 04 Jun 2009 16:47:00 -0400, HK wrote:

BTW, there are lots of quality gold-toned fishing reels from Shimano and
others where the plating has worn off.

You can find it very difficult to measure the hardness of very thin
coatings, but titanium nitride is estimated at Rockwell C 85. It is
coated on to drill bits, steel knife cutting edges, and the titanium
handles on my Buck folding knife. It is yellow in color, and is used
for decoration as well as wear resistance. You can color anodize
aluminum that color, but I don't believe the coating is as abrasion
resistant as the nitride, notwithstanding the fact the all aluminum
has a coating of sapphire, transparent aluminum oxide.

Casady