Nanowear of Hafnium Diboride Thin Films

Chemical Vapor Deposition-grown HfB2 films were subjected to nanowear testing at normal loads of 50-500 mu N. The material response was investigated by measuring residual wear depths and wear scar roughness and by calculating wear rates and specific energies. Films annealed for 1 h at 800 degrees C showed significant reduction in wear rate and required a higher critical energy for wear, compared to as-deposited HfB2 films. Analysis of roughness of the worn scars revealed that plowing effect dominates at higher loads (200-500 mu N), whereas at lower loads, asperity flattening dominates. The excellent response of annealed HfB2 films to nanotribological testing demonstrates the potential of these films for applications requiring high wear resistance at the nanoscale.