Comparison of (Cr0.75Al0.25)N Coatings Deposited by Conventional and High Power Pulsed Magnetron Sputtering

Pulsed high power plasma discharges offer high potential by means of developing new coating systems with outstanding characteristics and enhanced application possibilities. To get high-performance materials the plasma physics of sputtering, transport and deposition during a High Power Pulse Magnetron Sputtering (HPPMS) process have to be investigated and correlated to coating characteristics as well as compound and system characteristics. Every coating has to be adapted to the specific application which it addresses. In the frame of this research project the HPPMS technology is used to investigate coating systems regarding their possibility to be used in injection molding processes. This manuscript shows a first comparison of conventional sputtered ternary Cr-Al-N by direct current (DC) magnetron sputtering (MS), pulsed middle frequency (MF) MS and Cr-Al-N deposited by HPPMS. The Cr:Al ratio was kept constant at about 75 : 25 (at-%). All three coatings were analyzed regarding thickness, morphology, chemical composition, texturing and mechanical properties like hardness and Young's modulus. Furthermore, all three coatings were deposited on the complex structure of a gear wheel to obtain the uniformity of the coating. The results show that HPPMS-(Cr0.75Al0.25)N coatings cannot provide outstanding advantages regarding mechanical properties or advantages in morphology compared to conventionally deposited coatings. However, HPPMS shows a completely different phase texturing measured by X-ray diffraction and a better uniformity on complex components.