Moisture Effects on Nanowear of Gold Films
  Nanowear properties of sputtered Au films in dry and wet environments were investigated using a scanning nanoindenter. Gold exhibits over 10 times higher wear rate in water compared to air at the same normal load of 10 microN. The friction coefficient obtained from scratch tests remained constant at 0.2 regardless of the testing conditions. Au surface roughness increased from 3 to 8 nm after 200 wear cycles in air. Surface ripples, 200 nm high developed on the Au film surface after 200 wear cycles in water. Film scratch hardness compares well with the nanoindentation hardness. 
Xiaolu Pang, Alex A. Volinsky, Kewei Gao