Nitride films are ubiquitous in their use as hard, wear-resistant coatings. In this work, we help contribute to a scale-bridging model, helping build understanding of how initial plasma parameters affect the mechanical properties of the final coating system. To this end, we study the effect of transition metal species and oxygen content in transition metal aluminium (oxy)nitride coatings.

Fracture toughness measurements are made using micro-cantilever bending tests, showing a strong correlation between elastic modulus and toughness. These tests are extended up to elevated temperatures to study the performance at operating temperatures, where a strong decrease in fracture toughness is seen. However, this recovers on cooling, implying that this reduction in performance is not due to degradation of the material.