Topic: Effects of Nickel Plating on 6061-T6 Aluminum

Our supplier of our pulleys has started to use electroless nickel plating on their pulleys bushings systems.  Because the pulleys attach via friction (clamping onto the motor shaft) we are fearful that slip torque of the pulleys will be reduced.  The supplier told us that coating the pulleys bushings will not change the slippage ratings.

What is your thoughts?  Should I get more specifics as to the plating process?  

How hard is the plating?  Would the plating damage the motor shafts if  I were to run some tests to see when a plated pulley slips as opposed to a non plating pulley?