Aluminum-rich HPPMS (Cr1−xAlx)N coatings deposited with different target compositions and at various pulse lengths

• Al-rich HPPMS (Cr1−xAlx)N deposited with various plugged targets and pulse lengths.
• Increase of peak power density from 0.32 kW/cm2 to 0.86 kW/cm2.
• Constant deposition rate using different Al-rich targets at the same pulse length.
• Aluminum content was varied between x = 68 at% and x = 76 at%.
• Al-rich (Cr0.30Al0.70)N with high hardness (30 GPa) and moderate modulus (421 GPa).

Target properties and pulse configuration are important factors in high power pulsed magnetron sputtering. The present work deals with analyses of the effects of the pulse length, i.e., duty cycle on the HPPMS process and on the properties of Al-rich (Cr1−xAlx)N coatings deposited with plugged targets in an industrial scale unit. The results showed that the peak power density increased from 0.32 kW/cm2 to 0.86 kW/cm2 as the pulse length decreased from ton = 200 μs to 40 μs. (Cr1−xAlx)N coatings with a high aluminum content between x = 68 at% and x = 76 at% were produced. The deposition rate reveals a constant behavior using different Al-rich targets at the same pulse length. A mixture of cubic and hexagonal (Cr1−xAlx)N phases was found for each coating. Furthermore, a finer and denser morphology as well as a smoother surface were observed at reduced pulse length compared to large pulse configuration due to the high peak current and power density. The maximum hardness of HU = 30.0 GPa and a moderate elastic modulus of EIT = 421 GPa were achieved for the (Cr0.30Al0.70)N coating deposited at a pulse length of ton = 40 μs, i.e., duty cycle of 2%.