Thermal stability of alumina thin films containing γ-Al2O3 phase prepared by reactive magnetron sputtering

The present work investigates the microstructure and chemical composition of macroparticles incorporated in arc evaporated (Al,Cr)2O3 coatings. According to scanning and transmission electron microscopy analysis, two different types of macroparticles with a distinct difference in their shape and a noticeable variation in their chemical composition, i.e. the Al/Cr ratio, can be distinguished. In addition, the transformations on the surface of the corresponding Al–Cr compound cathodes during the evaporation process in O2 atmosphere are studied by scanning electron microscopy and X-ray diffraction. Beside the virgin cathode material, a reaction layer consisting of various intermetallic AlxCry phases with a fine-grained morphology and pillar-shaped Al2O3 islands was found. Correlations between the origin of the macroparticles and the observed modifications at the surface of the Al–Cr cathode are discussed.

Cathodic arc deposition of (Al,Cr)2O3: Macroparticles and cathode surface modifications

Structural and mechanical properties of Cr–Al–O–N thin films grown by cathodic arc deposition

http://liu.diva-portal.org/smash/get/diva2:398416/FULLTEXT02.pdf

Face-centered cubic (Al1 − xCrx)2O3

The development of new coatings with superior functionalities for high performance cutting tools is a key challenge in manufacturing. In this context, the synthesis of aluminium oxide and derivative oxide thin films is attracting large scientific and technical interests. The present paper addresses fundamental materials science-based aspects of the physical vapour deposition (PVD) growth of Al–Cr–O thin films at a substrate temperature of 500 °C. A combinatorial experimental approach was chosen to describe the growth and microstructure evolution of Al–Cr–O thin films by means of reactive r.f. magnetron sputtering. A segmented target consisting of two half plates of Al and Cr was used for the deposition carried out under stationary conditions in a laboratory-scale PVD coater. Opposite to the cathode five substrate samples were placed in a line. The r.f. cathode power was set to 500 W and the r.f. substrate bias was set to − 100 V. The total gas pressure was kept constant at 0.4 Pa for all experiments with a fixed ratio of oxygen to argon gas flow. Detailed results on the coatings composition, constitution, microstructure and properties as a function of the elemental composition are presented. X-Ray Diffraction (XRD), X-Ray Reflection (XRR), Transmission Electron Microscopy (TEM) and Electron Probe Microanalysis (EPMA) studies prove the growth of nanocrystalline, stoichiometric, metastable corundum-like solid solution strengthened α-(Al 1 −  x ,Cr x ) 2 O 3 thin films with a high degree of crystallinity, grain sizes between 27 ± 6 nm (in the case of Al-rich coatings) and 44 ± 17 nm (in the case of Cr-rich coatings), Vickers micro hardness values up to 2620 ± 80 HV0.05 and thin film densities between 4.00 g/cm³ (in the case of Al-rich coatings) and 4.86 g/cm³ (in the case of Cr-rich coatings).

Combinatorial approach to the growth of α-(Al1 − x,Crx)2O3 solid solution strengthened thin films by reactive r.f. magnetron sputtering

Synthesis of Al–Cr–O–N thin films in corundum and f.c.c. structure by reactive r.f. magnetron sputtering

Die vorliegende Erfindung betrifft einen hexagonalen Mischkristall aus einem Al-Cr-O-N Stoffsystem, ein Verfahren zu seiner Herstellung und seine Verwendung. Der hexagonaler Mischkristall aus einem Al-Cr-O-N Stoffsystem mit der Formel α-(Alx, Cr1-x)2+δ(O1-y, Ny)3, wobei α die hexagonale Gitterstruktur bezeichnet, x einen Wert von 0,1 bis 0,9 hat, y einen Wert von 0,05 bis 0,2 hat und δ einen Wert von –0,6 bis 0 aufweist. Die Erfindung betrifft weiterhin ein Verfahren zur Herstellung eines hexagonalen Mischkristalls aus einem Al-Cr-O-N Stoffsystem. Dies ist mittels physikalischer Gasphasenabscheidung oder einer Kombination aus physikalischer und chemischer Gasphasenabscheidung moglich. Die Schichten mit der erfindungsgemasen Zusammensetzung und Struktur sind aufgrund ihrer Hartewerte besonders fur die Verwendung als Hartstoffschicht geeignet.

Hexagonaler Mischkristall aus einem Al-Cr-O-N Stoffsystem

The invention relates to a method for producing a coated cutting tool comprising depositing a 0.5-10 µm nitride layer which is a nitride one or more of Ti, Zr, Hf, V, Ta, Nb, Si, Cr and Al, onto a substrate followed by depositing Al or Al+Me, further followed by depositing a 0.1-5 µm oxide layer being an (Al a Me 1-a ) 2 O 3 layer, 0.05≤a≤1, Me is one or more of Ti, Mg, Ag, Zr, Si, V, Fe, Hf, B and Cr, said layers are deposited by magnetron sputtering. Also, a coated cutting tool comprising a substrate with a coating comprising said nitride layer and oxide layer, the coating has inclusions of (Al,Me,O) in the oxide layer at the interface between the nitride layer and the oxide layer, and/or a layer of (Al,Me,O) situated inbetween the nitride layer and the oxide layer.

A method for producing a coated cutting tool and a coated cutting tool

The present invention relates to a hexagonal mixed crystal made of an Al-Cr-O-N substance system, to a method for production thereof and to the use thereof. The hexagonal mixed crystal made of an Al-Cr-O-N substance system has the formula a- (Alx,Cr1-x)2+d (O1-y,Ny)3, where a denotes the hexagonal lattice structure, x has a value from 0.1 to 0.9, y has a value from 0.05 to 0.2, and d has a value from -0.6 to 0. The invention further relates to a method for producing a hexagonal mixed crystal made of an Al-Cr-O-N substance system. This is possible by means of physical vapour deposition or a combination of physical and chemical vapour deposition. Because of the hardness values that the coatings comprising the composition and structure according to the invention have, they are particularly suited for use as a hard material coating.

Diechle Dominic

Papers

Combinatorial approach to the growth of α-(Al1 − x,Crx)2O3 solid solution strengthened thin films by reactive r.f. magnetron sputtering

Synthesis of Al–Cr–O–N thin films in corundum and f.c.c. structure by reactive r.f. magnetron sputtering

Hexagonaler Mischkristall aus einem Al-Cr-O-N Stoffsystem

A method for producing a coated cutting tool and a coated cutting tool

Hexagonal mixed crystal made of an al-cr-o-n substance system