TY - THES

T1 - Influence of pulsed bias on CrN coatings prepared by reactive magnetron sputtering

AU - Grasser, Stephan

N1 - embargoed until null

PY - 2008

Y1 - 2008

N2 - The physical vapor deposition (PVD) technique is based on the condensation of particles from the vapor phase and subsequent growth. Here, the number and the energy of the impinging particles are crucial to the development of the microstructure and thus the properties of the coating. Within this work, the attempt has been made to combine the positive effects of plasma based electron bombardment (PBEB) as well as ion bombardment on the microstructure of CrN hard coatings. Therefore, CrN coatings were deposited by reactive unbalanced magnetron sputtering on silicon substrates. The substrate holder was biased by an ENI RPG50 power supply which was driven in both, DC and asymmetric bipolar pulsed mode. By this setup a negative base bias voltage combined with positive pulses in the kHz range with were applied, thus introducing a PBEB as well as an ion bombardment of the surface of the coating. The microstructure of the CrN coatings was investigated by means of scanning electron microscopy. Chemical analysis of the CrN coatings was conducted by energy and wavelength dispersive X-ray analysis. X-ray diffraction (XRD) measurements with subsequent pseudo-Voigt analysis provided data on phase composition as well as crystallite size. Mechanical properties such as hardness and residual stresses were determined by means of the nanoindentation technique and biaxial-stress measurements.

AB - The physical vapor deposition (PVD) technique is based on the condensation of particles from the vapor phase and subsequent growth. Here, the number and the energy of the impinging particles are crucial to the development of the microstructure and thus the properties of the coating. Within this work, the attempt has been made to combine the positive effects of plasma based electron bombardment (PBEB) as well as ion bombardment on the microstructure of CrN hard coatings. Therefore, CrN coatings were deposited by reactive unbalanced magnetron sputtering on silicon substrates. The substrate holder was biased by an ENI RPG50 power supply which was driven in both, DC and asymmetric bipolar pulsed mode. By this setup a negative base bias voltage combined with positive pulses in the kHz range with were applied, thus introducing a PBEB as well as an ion bombardment of the surface of the coating. The microstructure of the CrN coatings was investigated by means of scanning electron microscopy. Chemical analysis of the CrN coatings was conducted by energy and wavelength dispersive X-ray analysis. X-ray diffraction (XRD) measurements with subsequent pseudo-Voigt analysis provided data on phase composition as well as crystallite size. Mechanical properties such as hardness and residual stresses were determined by means of the nanoindentation technique and biaxial-stress measurements.

KW - PVD reactive magnetron sputtering CrN pulsed bias plasma based electron bombardment microstructure hardness residual stress

KW - PVD reaktives Kathodenzerstäuben CrN gepulstes Bias Plasma basiertes Elektronenbombardement Mikrostruktur Härte Eigenspannung

M3 - Diploma Thesis

ER -