Browsing by Author "Lee, Jyh-Wei"

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Mechanical and tribological properties evaluation of cathodic arc deposited CrN/ZrN multilayer coatings
(2011-12-25)
Huang, Sung-Hsiu
;
Chen, Siao-Fan
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Kuo, Yu-Chu
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Wang, Chaur-Jeng
;
Lee, Jyh-Wei
Five nanostructured CrN/ZrN multilayer coatings were deposited periodically by cathodic arc evaporation. The bilayer periods of the CrN/ZrN multilayer coatings were controlled in the range of 5 to 30 nm. The structures and bilayer period of the multilayer coatings were characterized by an X-ray diffractometer. The microstructures of thin films were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Nanoindentation, scratch tests, Daimler-Benz Rockwell-C (HRC-DB) adhesion tests, microhardness and pin-on-disk wear tests were used to evaluate the hardness, adhesion, indentation toughness and tribological properties of thin films, respectively. It was found that the hardness and tribological properties were strongly influenced by the bilayer period of the CrN/ZrN multilayer coatings. An optimal combination of mechanical properties and excellent tribological behavior was found for a coating with a critical bilayer period of 30 nm. (C) 2011 Elsevier B.V. All rights reserved.
Microstructure and mechanical properties evaluation of cathodic arc deposited CrCN/ZrCN multilayer coatings
(2019-09-30)
Huang, Sung-Hsiu
;
Tong, Cheng-Yi
;
Hsieh, Tsung-Eong
;
Lee, Jyh-Wei
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材料科學與工程學系
For the development of advanced nanoscale multilayer protective coatings, proper design of microstructure and chemical composition of carbon containing sequential transition metal nitride nanolayers is an important issue. In this work, five different nanostructured CrCN/ZrCN multilayer coatings were deposited periodically by cathodic arc evaporation. The bilayer period of the CrCN/ZrCN multilayer coatings was kept at 20 nm. The C2H2 gas flow ratio was adjusted from 6.3 to 20.0% for achieving CrCN/ZrCN multilayer coatings with 2.3-4.2 at.% carbon content. Nanolaminated CrCN and ZrCN nitride layers and thin amorphous carbon nitride mixed nanolayers -5 nm thick were obtained as the carbon content reached 4.2 at.%. It was found that the hardness and adhesion quality were strongly improved by the carbon addition to the CrCN/ZrCN multilayer coatings. An increase of 2.6-4.6 GPa in hardness was found for the CrCN/ZrCN multilayer coatings due to the balance of solution hardening effect of carbon atoms and the softening by the amorphous mixed nanolayer. An optimal combination of high hardness, 28.9 GPa, and good adhesion, 41 N of upper critical load were achieved when the carbon content was 4.2 at.% for the CrCN/ZrCN multilayer coatings. (C) 2019 Elsevier B.V. All rights reserved.
Nanomechanical Properties and Fracture Behaviors of Bi3Se2Te Thin Films by Nanoindentation
(2017-11-01)
Jian, Sheng-Rui
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Phuoc Huu Le
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Luo, Chih-Wei
;
Jenh-YihJuang
;
Wu, Kaung-Hsiung
Polycrystalline Bi3Se2Te thin films were grown on c-plane sapphire substrates by pulsed laser deposition (PLD) in helium atmosphere. Two different helium gas pressures of P-He = 2.7x10(-3) and 8.7x10(1) Pa were used during deposition. The microstructure, surface morphology, and nanomechanical properties of the obtained Bi3Se2Te films were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and nanoindentation, respectively. Results indicated that the films deposited under different P-He's all exhibited highly c-axis-oriented characteristics with granular morphology. Nevertheless, the surface roughness showed strong dependence on PHe, increased from 1.3 nm to 11.8 nm for films grown at lower and higher P-He, respectively, suggesting a prominent role played by the helium gas in the nucleation and growth behavior during deposition. The Weibull statistical analysis was adopted to calculate the characteristic values of hardness and Young's modulus of the Bi3Se2Te films. In addition, the values of the fracture toughness and the nanoindentation-induced fracture behaviors of Bi3Se2Te thin films were also investigated and the results indicated that films with smaller grain size and larger surface roughness give rise to larger fracture toughness.
The effect of Cr/Zr chemical composition ratios on the mechanical properties of CrN/ZrN multilayered coatings deposited by cathodic arc deposition system
(2013-09-01)
Chen, Siao-Fan
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Kuo, Yu-Chu
;
Wang, Chaur-Jeng
;
Huang, Sung-Hsiu
;
Lee, Jyh-Wei
CrN/ZrN multilayer coatings with various Cr/Zr chemical compositions ratio were fabricated by a cathode arc deposition system. The Cr/Zr atomic ratios of the CrN/ZrN multilayer coatings were controlled, ranging from I to 2.5. The chemical composition of CrN/ZrN multilayer thin films was determined by a field emission electron probe microanalyzer (FE-EPMA). The phase composition of multilayer coatings was analyzed by a glancing angle X-ray diffractometer. Microstructures of the thin films were examined by field emission scanning electron microscopy (FE-SEM). Nanoindentation, the Daimler Benz Rockwell-C (HRC-DB) adhesion, microhardness, pin-on-disc wear tests and scratch tests were used to evaluate the hardness, adhesion, toughness and tribological properties of the thin films, respectively. It was found that the hardness and tribological properties were strongly influenced by the Cr/Zr chemical composition ratios of the CrN/ZrN multilayer coatings. Optimal mechanical properties and the maximum hardness of 28 GPa were achieved for the coating when the Cr/Zr atomic ratio was 2.1. (C) 2012 Elsevier B.V. All rights reserved.
The Indentation-Induced Pop-in Phenomenon and Fracture Behaviors of GaP(100) Single-Crystal
(2019-11-01)
Chiu, Yi-Jui
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Jian, Sheng-Rui
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Lee, Jyh-Wei
;
Juang, Jenh-Yih
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電子物理學系
The deformation behaviors and fracture features of GaP(100) single-crystal are investigated by using nano- and micro-scale indentation techniques. The hardness and Young's modulus were measured by nanoindentation using a Berkovich diamond indenter with continuous contact stiffness measurements (CSM) mode and the values obtained were 12.5 +/- 1.2 GPa and 152.6 +/- 12.8 GPa, respectively. In addition, the characteristic "pop-in" was observed in the loading portion of load-displacement curve, which was caused by the nucleation and/or propagation of dislocations. An energetic estimation methodology on the associated nanoindentation-induced dislocation numbers resulting from the pop-in events was discussed. Furthermore, the Vickers indentation induced fracture patterns of GaP(100) single-crystal were observed and analyzed using optical microscopy. The obtained fracture toughness K-C of GaP(100) single-crystal was similar to 1.7 +/- 0.1 MPa.m(1/2), which is substantially higher than the K-IC values of 0.8 MPa.m(1/2) and 1.0 MPa.m(1/2) previously reported for of single-crystal and polycrystalline GaP, respectively.