Splat Formation and Adhesion Mechanisms of Cold Gas-Sprayed Al Coatings on Al2O3 Substrates
Splat Formation and Adhesion Mechanisms of Cold Gas-Sprayed Al Coatings on Al2O3 Substrates
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DOI：
10.1007/s11666-013-9966-z
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发表时间：
2013
影响因子：
3.1
通讯作者：
R. Drehmann;T. Grund;T. Lampke;B. Wielage;K. Manygoats;T. Schucknecht;D. Rafaja
中科院分区：
文献类型：
--
作者：
R. Drehmann;T. Grund;T. Lampke;B. Wielage;K. Manygoats;T. Schucknecht;D. Rafaja
近年来，通过冷气喷涂（CGS）对陶瓷进行金属化已成为众多出版物的焦点。然而，金属涂层在非韧性基体上的结合机理仍不完全清楚。以前的研究表明，钛涂层沉积在陶瓷上的绝热剪切过程和异质外延生长诱导的再结晶的组合可能是负责光滑的陶瓷表面上施加的涂层的高附着强度。在目前的工作中，CGS铝和氧化铝基板之间的界面形成检查不同的颗粒尺寸和基板温度。此外，随后的热处理的抗拉强度和硬度的影响进行了研究。用扫描电子显微镜观察了单个颗粒的溅射形成，用高分辨透射电子显微镜研究了Al/Al 2 O3界面。初步结果表明，在亚微米级粗糙度的多晶衬底上，Al与Al_2 O_3之间的异质外延是主要的键合机制，而在纳米级粗糙度的单晶蓝宝石（α-Al_2 O_3）衬底上，Al与Al_2 O_3之间的异质外延是主要的键合机制。CGS铝的变形诱导再结晶促进了异质外延生长。
The metallization of ceramics by means of cold gas spraying (CGS) has been in the focus of numerous publications in the recent past. However, the bonding mechanism of metallic coatings on non-ductile substrates is still not fully understood. Former investigations of titanium coatings deposited on corundum revealed that a combination of recrystallization induced by adiabatic shear processes and hetero-epitaxial growth might be responsible for the high adhesion strengths of coatings applied on smooth ceramic surfaces. In the present work, the interface formation between CGS aluminum and alumina substrates is examined for different particle sizes and substrate temperatures. Furthermore, the influence of subsequent heat treatment on tensile strength and hardness is investigated. The splat formation of single particles is examined by means of scanning electron microscopy, while a high resolution transmission electron microscope is used to study the Al/Al2O3interface. First results suggest that mechanical interlocking is the primary adhesion mechanism on polycrystalline substrates having the roughness in sub-micrometer range, while the heteroepitaxy between Al and Al2O3can be considered as the main bonding mechanism for single-crystalline sapphire (α-Al2O3) substrates with the surface roughness in nanometer range. The heteroepitaxial growth is facilitated by deformation-induced recrystallisation of CGS aluminum.