微/奈米氧化鋁/氧化鈦熔射塗層之噴覆與特性研究

Deposition and Characterization of Micro/Nano crystalline Alumina/Titania Thermal Spray Coatings

傅冠中(Kuan-Chung Fu)

指導教授 ： 蘇程裕

國立臺北科技大學/機電學院/製造科技研究所/碩士(2010年)

摘要

本研究利用奈米Al2O3、TiO2與h-BN粉末為起始原料，以噴霧造粒技術製備出二元相Al2O3/TiO2與三元相Al2O3/TiO2/h-BN熔射粉末，分別採用電漿熔射技術製備具有奈米結構的二元與三元相熔射塗層，並與傳統微米Al2O3-40wt.%TiO2熔射塗層相互作比較。熔射塗層針對其表面形態、微結構、硬度、孔隙率等進行分析，並研究塗層的機械性能與磨耗特性，以探討塗層失效的磨耗機理。
研究結果顯示，奈米結構塗層主要由γ-Al2O3相的完全熔融區和奈米顆粒α-Al2O3的部分熔融區所組成的雙相結構，傳統微米塗層主要是由γ-Al2O3相的完全熔融區所組成。其中，奈米Al2O3-40wt.%TiO2塗層之硬度、孔隙率與抗磨耗特性為三種塗層中最佳，在磨耗過程中，微米與奈米Al2O3-40wt.%TiO2塗層均以剝落磨耗為主，且包括磨粒磨耗的磨耗機制，由於奈米結構的部分熔融區對裂紋的形成與擴展有抑制作用，是塗層韌性與抗磨耗性提高的主要原因。
添加h-BN的奈米Al2O3-40wt.%TiO2塗層，其硬度、孔隙率與抗磨耗性無顯著提升，原因推測為h-BN與Al2O3、TiO2潤濕性不佳和塗層中h-BN的分佈情形有關，當h-BN彼此團聚分佈於層間處時，h-BN扮演著層間分離機制，其塗層以大面積剝落磨耗為主。

關鍵字

電漿熔射 ； 氮化硼 ； 氧化鋁/氧化鈦 ； 噴霧造粒 ； 潤滑 ； 磨耗

並列摘要

This study adopts Al2O3, TiO2 and h-BN nano-powder as starting materials and uses spray drying to prepare for pray powder of Al2O3/TiO2 of binary phase and Al2O3/TiO2/h-BN of ternary phase spray powder. Plasma spray technology is used to fabricate spray coatings of binary and ternary phase respectively and compared with that of Al2O3-40wt.%TiO2 spray coating of conventional micron. The morphology, mirco-structure, hardness and porosity of spray coating are analyzed and its mechanical properties and wear characteristics are researched to deal with the wear mechanism of coating failure.
The results show that the nano-structure of coating is the two-phase structure composed of γ- Al2O3 complete melting and α-Al2O3 partial melting. The hardness, porosity and against-wear properties of nano- Al2O3-40wt.%TiO2 is optimum of the three. During the wear process, mirco- and nano Al2O3-40wt.%TiO2 coatings mostly have wear characteristics, including wear mechanism of abrasive wear. The partial melting of nano-structure can inhibit the formation and development of cracks – the main reason of the elevation of toughness and against-wear characteristics of coating.
The hardness, porosity and against-wear of nano- Al2O3-40wt.%TiO2 coating added into h-BN powder can not be enhanced significantly. The main reason is the structure of h-BN and the dispersion of h-BN in the coating. When h-BN amasses and disperses in the coating, h-BN plays the role of layer separation mechanism and its coating mostly has the properties of large-area wear.

並列關鍵字

Plasma spray ； Boron Nitride ； Alumina/Titania ； Spray Drying ； Lubrication ； Wear

參考文獻

[25] 宋慧琳，噴霧造粒鐵粉之性質及其熱脫脂行為，碩士論文，台灣大學，臺北，2006。

[1] W. A. Saywell, “Thermal Spray Industry Continues to Develop,” Metal Powder Report, vol. 51, no. 4, 1996, pp. 34-37.

[2] H. Herman, S. Sampath and R. McCune, “Thermal Spray：Current Status and Future Trends,” MRS Bulletin, vol. 25, no. 7, 2000, pp. 17-25.

[3] B. S. Schorr, K. J. Stein and A. R. Marder, “Characterization of Thermal Spray Coatings,” Materials Characterization, vol. 42, no. 2, 1999, pp. 93-100.

[4] S. B. Mishra, S. Prakash and K. Chandra, “Studies on erosion behavior of plasma sprayed coatings on a Ni-based superalloy,” Wear, vol. 260, no. 4-5, 2000, pp. 422-432.