Zinc? I've never, ever seen electrical connectors with zinc pins. Tin or silver plate, yes, but never zinc.
With gold plating being so common these days, I'd opt for that. Anything but gold can be subject to fretting and other corrosion over time. Gold is not the best conductor though with silver and copper taking the top ratings there. Silver or silver alloys are most common for switch contacts where the mechanical action of the switch helps to counteract any corrosion that might develop over time.
Many lower cost receivers in various brands still use silver or tin plated pins for the servo / power connections.
Last edited by Truckracer; 03-11-2018 at 12:49 PM.