Nanowear of Hafnium Diboride Thin Films

Chemical Vapor Deposition-grown HfB₂ films were subjected to nanowear testing at normal loads of 50–500 μN. 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°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 μN), 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.