Thermal Stability of Alumina-based Hard Coatings
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TY - BOOK
T1 - Thermal Stability of Alumina-based Hard Coatings
AU - Edlmayr, Viktoria
N1 - no embargo
PY - 2014
Y1 - 2014
N2 - Within the present thesis, the thermal stability of sputtered and arc evaporated alumina-based coating materials was investigated in terms of changes of their morphology during thermal load. Since alumina exists, besides the thermodynamically stable corundum structured α-Al2O3, in a variety of metastable modifications, for their application as protective coatings on cutting tools, the knowledge of their thermal stability is of vital importance. Therefore, different metastable Al2O3 coatings were produced by magnetron sputtering. In all cases, transformation into the α-Al2O3 phase occurred at temperatures of about 1100 °C. In order to meet the demand of low deposition temperatures and thus to synthesize a protective coating on thermally sensitive cutting tools, in a second attempt the α-Al2O3 phase was stabilized by the isostructural Cr2O3 phase, forming a corundum-based (AlxCr1-x)2O3 solid solution. The solid solutions synthesized by arc evaporation were investigated and the thermal stability against decomposition was also determined. To conclude, the demand for protective coatings, which can be synthesized at low deposition temperatures and exhibit a sufficient thermal stability, is fulfilled by the metastable corundum-based (AlxCr1-x)2O3 solid solutions. These coatings might be interesting candidates for high-temperature and cutting applications, where high performance materials are needed.
AB - Within the present thesis, the thermal stability of sputtered and arc evaporated alumina-based coating materials was investigated in terms of changes of their morphology during thermal load. Since alumina exists, besides the thermodynamically stable corundum structured α-Al2O3, in a variety of metastable modifications, for their application as protective coatings on cutting tools, the knowledge of their thermal stability is of vital importance. Therefore, different metastable Al2O3 coatings were produced by magnetron sputtering. In all cases, transformation into the α-Al2O3 phase occurred at temperatures of about 1100 °C. In order to meet the demand of low deposition temperatures and thus to synthesize a protective coating on thermally sensitive cutting tools, in a second attempt the α-Al2O3 phase was stabilized by the isostructural Cr2O3 phase, forming a corundum-based (AlxCr1-x)2O3 solid solution. The solid solutions synthesized by arc evaporation were investigated and the thermal stability against decomposition was also determined. To conclude, the demand for protective coatings, which can be synthesized at low deposition temperatures and exhibit a sufficient thermal stability, is fulfilled by the metastable corundum-based (AlxCr1-x)2O3 solid solutions. These coatings might be interesting candidates for high-temperature and cutting applications, where high performance materials are needed.
KW - Aluminiumoxid
KW - Phasenumwandung
KW - Physikalische Gasphasenabscheidung (PVD)
KW - Kathodenzerstäubung
KW - Lichtbogenverdampfung
KW - Glühung
KW - Thermische Stabilität
KW - TEM
KW - EELS
KW - Al2O3
KW - α-Al2O3
KW - γ-Al2O3
KW - (Al
KW - Cr)2O3
KW - Al-Cr-O
KW - Alumina
KW - Phase transformation
KW - PVD coatings
KW - Sputtering
KW - Arc evaporation
KW - Annealing
KW - Thermal stability
KW - TEM
KW - EELS
KW - Al2O3
KW - α-Al2O3
KW - γ-Al2O3
KW - (Al
KW - Cr)2O3
KW - Al-Cr-O
M3 - Doctoral Thesis
ER -