High hardness, low Young's modulus and low friction of nanocrystalline ZrW2 Laves phase and Zr1−xWx thin films

• Published in: The Journal of physics and chemistry of solids 2012-04, Vol.73 (4), p.554-558
• Main Authors: Horwat, D., Jimenez-Pique, E., Pierson, J.F., Migot, S., Dehmas, M., Anglada, M.
• Format: Article
• Language: English
• Subjects: A. Intermetallic compounds; A. Nanostructures; A. Thin films; Amorphous materials; D. Mechanical properties; Enginyeria dels materials; Friction; Grain boundaries; Hardness; Intermetallic compounds; Laves phase; Materials ceràmics; Mechanical properties; Modulus of elasticity; Nanocrystals; Nanoestructures; Nanostructures; Thin films; Zirconium; Àrees temàtiques de la UPC
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/j.jpcs.2011.12.009

Zr1−xWx nanocrystalline films of Zr-W solid solutions and ZrW2 Laves phase were synthesized by magnetron co-sputtering. Large values of the H/E ratio up to 0.09 are observed for grain sizes in the nanometer range along with a hardness above 10GPa and Young's modulus below 230GPa. H/E values are correlated with the developed surface of grain boundaries suggesting an elastic deformation mostly handled by the grain boundaries. This is associated to friction coefficients comparable to those of metallic glass surfaces. In contrast to fragile bulk Laves phases, no cracks were detected at the film surface after indentation and scratch test of nanocrystalline ZrW2. The friction coefficient of such films against diamond tip was in the range 0.08–0.15, similarly to metallic glass surfaces. ► Nanocrystalline films were formed by co-sputtering Zr and W targets. ► Nanostructured films exhibit high hardness and low Young's modulus. ► Associated friction coefficients are in the 0.08–0.15 range.