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You searched for subject:(ultrasonic mechanical coating AND armoring). Showing records 1 – 2 of 2 total matches.

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NSYSU

1. Hsu, Yeh-chun. Evaluation and investigation of bio-corrosion resistance enhancement for hydroxyapatite coating on biodegradable Mg alloy using electrodeposition and ultrasonic mechanical coating and armoring technique.

Degree: Master, Materials and Optoelectronic Science, 2017, NSYSU

For few decades, Ti-based, Fe-based and Co-based alloys have been widely investigated and applied in biomedical aspect. Yet, such alloys contain elements which will harm human body in high level; also, the Youngâs moduli of these alloys are much higher than that of human bone, which will induce stress-shielding effect, causing negative effect to surrounding tissues. Moreover, secondary surgery may be necessary to remove the implant while the tissue is fully healed. To solve these problems, a new embryonic field, biodegradable materials, was under investigated. Among this field, Mg alloys received most attention, which was mainly because Mg exists abundantly in human body; furthermore, Mg alloys possess closer Youngâs modulus to that of human bone. However, the obstacle for Mg alloys in biomedical application was its rapid degradation rate, which would lead to complete dissolution earlier than the tissue was sufficiently healed. Hence, the degradation rate control for Mg alloys became a critical issue. Scientists used surface modification methods to fabricate a coating on the material surface, achieving the goal for controlling the degradation rate. Hydroxyapatite (HA) was a suitable composition for biomaterial coating owing to its excellent biocompatibility and osteointegrity. Electrodeposition was a well-developed method featuring simple process, low deposition temperature and controllable for coating thickness and composition. In addition, Komarov et al. announced a new way that can fabricate coating through the mechanical method, the technique was called ultrasonic mechanical coating and armoring (UMCA). However, for this technique, its application on biomaterials was not observed yet; moreover, the corrosion study for the coating made by this technique was barely found. In this study, both electrodeposition and ultrasonic mechanical coating and armoring techniques were applied to form hydroxyapatite coating on AZ31B Mg alloy, respectively. Their corrosion resistance was also investigated and their extent of enhancement was under evaluation. In this study, through X-ray diffraction (XRD), electron dispersive spectroscopy (EDS) and Fourier-transformed infrared spectroscopy (FT-IR) analyses, it can be confirmed that both electrodeposition and ultrasonic mechanical coating and armoring (UMCA) can successfully fabricate hydroxyapatite coating on AZ31B surface. As for the most concerned corrosion resistance, according to electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (Tafel) results, coated AZ31B showed larger polarization resistance and decreased corrosion current density. Hence, it can be demonstrated the degradation rate of hydroxyapatite coating can be effectively inhibited, which makes Mg biodegradable materials step forward to practical application. Advisors/Committee Members: Che-Hsin Lin (chair), Jacob Chih-Ching Huang (committee member), Cheng-Tang Pan (chair).

Subjects/Keywords: ultrasonic mechanical coating and armoring; electrodeposition; hydroxyapatite coating; biodegradable materials; corrosion resistance

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hsu, Y. (2017). Evaluation and investigation of bio-corrosion resistance enhancement for hydroxyapatite coating on biodegradable Mg alloy using electrodeposition and ultrasonic mechanical coating and armoring technique. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0622117-183943

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Hsu, Yeh-chun. “Evaluation and investigation of bio-corrosion resistance enhancement for hydroxyapatite coating on biodegradable Mg alloy using electrodeposition and ultrasonic mechanical coating and armoring technique.” 2017. Thesis, NSYSU. Accessed April 24, 2019. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0622117-183943.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Hsu, Yeh-chun. “Evaluation and investigation of bio-corrosion resistance enhancement for hydroxyapatite coating on biodegradable Mg alloy using electrodeposition and ultrasonic mechanical coating and armoring technique.” 2017. Web. 24 Apr 2019.

Vancouver:

Hsu Y. Evaluation and investigation of bio-corrosion resistance enhancement for hydroxyapatite coating on biodegradable Mg alloy using electrodeposition and ultrasonic mechanical coating and armoring technique. [Internet] [Thesis]. NSYSU; 2017. [cited 2019 Apr 24]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0622117-183943.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hsu Y. Evaluation and investigation of bio-corrosion resistance enhancement for hydroxyapatite coating on biodegradable Mg alloy using electrodeposition and ultrasonic mechanical coating and armoring technique. [Thesis]. NSYSU; 2017. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0622117-183943

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


NSYSU

2. Tsai, Wei-Yu. Microstructures and properties of nano-grain refined 304 stainless steel and ceramic-powder inserted Al processed by ultrasonic surface mechanical attrition treatment.

Degree: PhD, Materials and Optoelectronic Science, 2017, NSYSU

In this research, we used Ultrasonic shot peening equipment as the tool, conducting nano-crystallization and surface mechanical coating experiments. Detailed experimental methods, results and discussion are presented separately as SMAT and UMCA parts in the manuscript. For the first part, the analytic modeling and one experimental assess of the ultrasonic surface mechanical attrition treatment (SMAT) are presented. The bombarding ball speed, induced energy, and the resulting sample hardness, experienced depth and grain size are incorporated into this model, based on harmonic longitudinal vibration motion of ultrasonic-wave-driven ball impact onto the sample surface. An experimental assessment by using a stainless steel flat sample is conducted, and the comparison of the model and experiment is reported. There appear some optimum SMAT working parameters for the best SMAT effect, locating within the ranges of 1-2 mm for the ball size, 8-10 m/s for the ball speed, 4-5x102 s-1 for the strain rate, and 70-75 mJ for the input energy. Beyond the optimum SMAT parameters, the sample surface would be subject to bombarding micro-cracking and the grain size would not be further reduced. Instead, the grain size becomes larger and the hardness becomes lower. The benefits from SMAT would become lower. We used 1050 aluminum alloys, which often serve as heat sink in light-emitting diode (LED) lighting, are inherent with a high thermal conductivity, but poor thermal total emissivity. Thus, high emissive coatings on the Al substrate can enhance the thermal dissipation efficiency of radiation. In this study, the ultrasonic mechanical coating and armoring (UMCA) technique was used to insert various ceramic combinations, such as Al2O3, SiO2, graphite and carbon nanotube to enhance thermal dissipation. Analytic models have been established to couple the thermal radiation and convection on the sample surface through heat flow equations. A promising match has been reached between the theoretical estimations and experimental measurements. With the adequate insertion of ceramic powders, the heat can be transferred to thermal radiation and emitted. The temperature of the Al plates and heat sinks can be lowered by 5â11°C, which is highly favorable for applications requiring cooling components. Advisors/Committee Members: Chih-Ching Huang (committee member), Che-Hsin Lin (chair), Cheng-Tang Pan (chair), Hsuan-Kai Lin (chair), Shian-Ching Jang (chair).

Subjects/Keywords: surface mechanical attrition treatment; grain refinement; fine grain strengthening; ultrasonic mechanical coating and armoring; heat dissipation coating

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Tsai, W. (2017). Microstructures and properties of nano-grain refined 304 stainless steel and ceramic-powder inserted Al processed by ultrasonic surface mechanical attrition treatment. (Doctoral Dissertation). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0426117-103718

Chicago Manual of Style (16th Edition):

Tsai, Wei-Yu. “Microstructures and properties of nano-grain refined 304 stainless steel and ceramic-powder inserted Al processed by ultrasonic surface mechanical attrition treatment.” 2017. Doctoral Dissertation, NSYSU. Accessed April 24, 2019. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0426117-103718.

MLA Handbook (7th Edition):

Tsai, Wei-Yu. “Microstructures and properties of nano-grain refined 304 stainless steel and ceramic-powder inserted Al processed by ultrasonic surface mechanical attrition treatment.” 2017. Web. 24 Apr 2019.

Vancouver:

Tsai W. Microstructures and properties of nano-grain refined 304 stainless steel and ceramic-powder inserted Al processed by ultrasonic surface mechanical attrition treatment. [Internet] [Doctoral dissertation]. NSYSU; 2017. [cited 2019 Apr 24]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0426117-103718.

Council of Science Editors:

Tsai W. Microstructures and properties of nano-grain refined 304 stainless steel and ceramic-powder inserted Al processed by ultrasonic surface mechanical attrition treatment. [Doctoral Dissertation]. NSYSU; 2017. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0426117-103718

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