• Journal of the Korean institute of surface engineering
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• v.38 no.6
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• pp.207-211
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• 2005

In this work a multi-layered nanostructured TiAIN/CrN superlattice coatings was synthesized using closed-field unbalanced magnetron sputtering method and the relationships between their superlattice period (1), micro-structure, hardness and elastic modulus were investigated. In addition, wear test at $500^{\circ}C$ and oxidation resistance test at $900^{\circ}C$ were performed to investigate high temperature properties of these thin films. The coatings were characterized in terms of microstructure and mechanical properties by transmission electron microscopy (TEM) and nano-indentation test. Results from TEM analysis showed that superlattice periods was inversely proportional to the jig rotation speed. The maximum hardness and elastic modulus of 37 GPa and 375 GPa were observed at superalttice period of 6.1 nm and 4.4 nm, respectively. An higher value of microhardness from TiAIN/CrN thin films than either TiAIN (30 GPa) or CrN (26 GPa) was noted while the elastic modulus was approximately an average of TiAIN and CrN films. These enhancement effects in superlattice films could be attributed to the resistance to dislocation glide across interface between the CrN and TiAIN layers. Much improved plastic deformation resistance ($H^3/E^2$) of 0.36 from TiAIN/CrN coatings was observed, compared with 0.15 and 0.16 from TiAIN and CrN, respectively. Also the wear resistance at $500^{\circ}C$ was largely increased than those of single TiAIN and CrN coatings and TiAIN/CrN coatings showed much reduced weight gain after exposure at $900^{\circ}C$ for 20 hours.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.251-254
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• 2002

The technique of high speed machining is widely studied in machining field. In this study, TiAIN single-layered and TiAIN/TiN double-layered coatings were applied to end-mill by an arc ion plating technique. Their performances were comparatively studied about cutting force, tool wear, tool life and surface roughness of workpiece under high speed cutting conditions. The TiAIN single-layer coated tool showed higher wear-resistance due to its higher hardness, while the TiAIN/TiN double-layer coated tool showed better performance for high metal removal, i.e., high fled per tooth condition due to its higher toughness. The surface roughness of the workpiece was not influenced by the wear amount of coated tools.

• Korean Journal of Materials Research
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• v.12 no.8
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• pp.676-681
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• 2002

Microstructure, mechanical properties, and oxidation resistance of TiAIN thin films deposited on quenched and tempered STD61 tool steel by arc ion plating were studied using XRD, XPS and micro-balance. The TiAIN film was grown with the (200) orientation. The grain size of TiAIN thin film decreased with increasing Al contents, while chemical binding energy increased with Al contents. When hard coating films were oxidized at $850^{\circ}C$ in air, oxidation resistance of both TiN and TiCN films became relatively lower since the surface of films formed non-protective film such as $TiO_2$. However, oxidation resistance of TiAIN film was excellent because its surface formed protective layer such as $_A12$$O_3$ and $_Al2$$Ti_{7}$$O_{15}$, which suppressed oxygen intrusion.

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.13-20
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• 1995

To develope a high precision TiAIN thin film resistor, TiAIN films were deposited on A1$_{2}$03 substrates by reactive planar magnetron cosputtering from Ti and Al targets in an Ar-N$_{2}$ atmosphere. The characteristics of the TiAIN thin film were controlled by changing of the R.F. power on Ti and Al targets, and the N$_{2}$ partial pressure. The high precision TiAIN thin film resistor with TCR(Temperature Coefficient of Resistance) of less than 10ppm/.deg. C was obtained under the R.F. power condition of 160(w)/240(w) to Ti and Al targets at the N$_{2}$ partial pressure of 7*10$^{-5}$ Torr. The composition of these films were investigated by XRD, SEM and EDS.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.135.2-135.2
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• 2005

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.388-392
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• 2003

As the machine tool industry progresses, the performance of cutting tools also needs to be of good quality and specialized. If the existing metal cutting tool tip is coated properly, its life would be longer and the machining of a difficult-to-cut material also could be possible. For the development of the high quality cutting tool, the applicabilities of TiAIN coating deposited by PVD on the cutting insert were experimentally investigated. The various measurements, such as, SEM micrograph, XRD pattern, AFM surface morphology, and hardness were performed to cross-check the possibility and availability of TiAIN coated tool in the field. The effects of it is successful and we hope to see good results in many fields.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.88-95
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• 2002

Fretting of fuel rod cladding material, Zircaloy-4 Tube, in PWR nuclear power plants must be reduced and avoided. Nowadays the introduction of surface treatments or coatings is expected to bean ideal solution to fretting damage since fretting is closely related to wear, corrosion and fatigue. Therefore, in this study the fretting wear experiment was peformed using TiAIN coated Zircaloy-4 tube as the fuel rod cladding and uncoated Zircaioy-4 tube as one of grids, especially concentrating on the sliding component. Fretting wear resistance of TiAIN coated Zircaloy-4 tubes was improved compared with that of TiN coated tubes and uncoated tubes and the fretting wear mechanisms were delamination and plastic flow following by brittle fracture at lower slip amplitude but severe oxidation and spallation of oxidative layer at higher slip amplitude.

• Journal of Powder Materials
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• v.4 no.3
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• pp.196-204
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• 1997

Joining of AIN ceramics to W and Cu by active-metal brazing method was tried with use of (Ag-Cu)-Ti alloy as insert-metal. Joints were produced under various conditions of temperature, holding time and Ti-content in (Ag-Cu) alloy Reaction and microstructural development in bonded interface were investigated through observation and analysis by SEM/EDS, EPMA and XRD. Joint strengths were measured by shear test. Bonded interface consists of two layers: an insert-metal layer of eutectic Ag- and Cu-rich phases and a reaction layer of TiN. Thickness of reaction layer increases with bonding temperature, holding time and Ti-content of insert-metal. It was confirmed that the growth of reaction layer is a diffusion-controlled process. Activation energy for this process was 260 KJ/mol which is lower than that for N diffusion in TiN. Maximum shear strength of 108 MPa and 72 MPa were obtained for AIN/W and AIN/Cu joints, respectively. Relationship between processing variables, joint strength and thickness of reaction layer was also explained.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.50-50
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.783-791
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• 2000

Increasing demands in productivity are propelling the development of new manufacturing methods like hard machining, high speed cutting (HSC) or machining of difficult to machine materials. In these processes the toois are subjected to very severe mechanical, tribological and thermal loads. They fail prematurely by abrasion, cratering, edge breakage and cold welding. The performance of such tools will be enhanced by better and more wear resistant coatings. The development of these new coatings shows a clear trend towards complex multi-component and multi-layer configurations. TiAIN multilayer coating belongs to these coatings for the new cutting tool generation. This paper tries to explain the benefits of the new coatings. TiAIN multilayer coating offers the following advantages: reduction of manufacturing costs. boost productivity, and lower coolant procurement, conditioning and disposal costs.