Characterization of Zr–Al–N films synthesized by a magnetron sputtering method

Pseudobinary Zr–Al–N films were synthesized by an inductively combined rf-plasma-assisted magnetron sputtering for the purpose of examining the prediction on the phase change in the T (transition metal)–Al–N pseudobinary system based on band parameters. Phase change from B1 structure to B4 was not verified by XRD and FTIR methods. Microhardness of these films showed a maximum hardness of about 46 GPa at the content of 30% AlN and then decreased drastically to about 28 GPa at the content of 35% AlN. The AlN content for the drastic change showed good agreement with the critical content predicted based on band parameters. Under the assumption that the drastic change of microhardness corresponds to the B1–B4 phase change, it is interpreted that appearance of two XRD peaks near 2θ=32° and 2θ=38° is attributed to the formation of the Zr–Al–N films with B1 structure. On the other hand, single XRD peak 2θ=38° in the Zr–Al–N film with ZrN/AlN=65:35 is assigned to B4 phase. Further, the existence of some amount of the B4 phase in the Zr–Al–N film with ZrN/AlN=70:30–80:20 is suggested from broadness in XRD peaks.