You can only anodize Ti. You can make the Ti pretty much any color you want depending on how many volts you put through your anodizing solution. Gold wont bond to Ti due to the different composition of the metals. Goes the same for laser welding. Cant weld gold and Ti together. it can be done but the weld or bond wont be strong, but as for coating Ti in gold, I havent heard of way of doing it yet, but I guess with anything it just takes time and someone will figure out a way if its even possible to do so.