TY - THES

T1 - High-temperature tribological investigations of CrAlN and CrAlSiN hard coatings in ambient and inert atmospheres

AU - Xia, Ao

N1 - embargoed until null

PY - 2016

Y1 - 2016

N2 - The aim of this thesis was to study the tribological properties of CrAlN and CrAlSiN hard coatings at elevated temperatures in ambient air and inert gas atmosphere. The coatings were synthesized by direct current magnetron sputter deposition in an industrial-scale system using Cr0.50Al0.50 and Cr0.45Al0.45Si0.10 composite targets. The tribological tests were performed in a ball-on-disk configuration at temperatures up to 700 °C using Al2O3 balls as counterparts. In terms of friction, slight variations were observed, but no correlation with the change in temperature and environment could be noticed..The wear coefficient as determined from 3D optical profilometry showed a non-uniform behavior. In the absence of oxygen, the wear of CrAlN was higher in the temperature range from 400 to 600 °C. In the case of CrAlSiN, the wear in inert atmosphere was generally lower, but an increasing trend with rising temperature similar to CrAlN was observed in both atmospheres. A subsequent analysis of the coating wear tracks and the wear scars on the Al2O3 counterparts by light optical microscopy and Raman spectroscopy revealed further details about the wear mechanisms present.

AB - The aim of this thesis was to study the tribological properties of CrAlN and CrAlSiN hard coatings at elevated temperatures in ambient air and inert gas atmosphere. The coatings were synthesized by direct current magnetron sputter deposition in an industrial-scale system using Cr0.50Al0.50 and Cr0.45Al0.45Si0.10 composite targets. The tribological tests were performed in a ball-on-disk configuration at temperatures up to 700 °C using Al2O3 balls as counterparts. In terms of friction, slight variations were observed, but no correlation with the change in temperature and environment could be noticed..The wear coefficient as determined from 3D optical profilometry showed a non-uniform behavior. In the absence of oxygen, the wear of CrAlN was higher in the temperature range from 400 to 600 °C. In the case of CrAlSiN, the wear in inert atmosphere was generally lower, but an increasing trend with rising temperature similar to CrAlN was observed in both atmospheres. A subsequent analysis of the coating wear tracks and the wear scars on the Al2O3 counterparts by light optical microscopy and Raman spectroscopy revealed further details about the wear mechanisms present.

KW - Hartstoffschichten

KW - Tribologie

KW - CrAlN

KW - CrAlSiN

KW - hard coatings

KW - tribology

KW - CrAlN

KW - CrAlSiN

M3 - Master's Thesis

ER -