Mechanical properties and tribological behavior of ZrO2 thin films deposited on sulfonated self-assembled monolayer of 3-mercaptopropyl trimethoxysilane
Mechanical properties and tribological behavior of ZrO2 thin films deposited on sulfonated self-assembled monolayer of 3-mercaptopropyl trimethoxysilane
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DOI：
10.1007/s11249-004-3593-2
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发表时间：
2005-04
影响因子：
3.2
通讯作者：
Jixue Wang;Xue-Lu Liu;Shufang Ren;Fang Guan;S. Yang
中科院分区：
文献类型：
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作者：
Jixue Wang;Xue-Lu Liu;Shufang Ren;Fang Guan;S. Yang
采用硅烷偶联剂（3-巯丙基）三甲氧基硅烷（MPTS）在单晶硅表面自组装成二维有机单层膜（MPTS-SAM）。MPTS-SAM膜中的末端-SH基团被原位氧化为-SO 3 H基团，赋予膜良好的化学吸附能力。然后利用-SO 3 H基团的化学吸附能力，在50 °C下，通过硫酸锆水溶液（Zr（SO 4）2·4 H2O）的水解反应，在氧化的MPTS-SAM上制备了ZrO 2薄膜。用椭圆偏振仪测量了薄膜的厚度，用原子力显微镜分析了薄膜的形貌和摩擦力。用纳米压痕仪（MET）测定了ZrO 2薄膜的硬度和弹性模量。在单向摩擦磨损试验机上研究了ZrO 2薄膜与AISI-52100钢球的宏观摩擦磨损行为，并在扫描电镜（SEM）上观察了磨损表面形貌。结果表明，沉积时间为100小时时，沉积的ZrO 2薄膜厚度约为100 nm，500 °C退火后厚度降至48 nm，800 °C加热后厚度进一步降至45 nm。沉积态的ZrO 2薄膜相对粗糙，均方根值约为1.0 nm，而在500和800 °C下加热的ZrO 2薄膜的表面粗糙度均方根值分别为0.76 nm和0.68 nm。在800 °C下退火的ZrO 2薄膜与沉积态ZrO 2薄膜和500 °C下退火的薄膜相比具有较高的硬度与弹性模量（H/E）比（0.062）。在低于2.0 N的正常载荷下，两种退火后的ZrO 2薄膜在与AISI-52100钢摩擦时均表现出优异的耐磨性，而800 °C退火后的ZrO 2薄膜具有更好的耐磨性。沉积态、500 °C退火态和800 °C退火态ZrO 2薄膜的摩擦磨损性能差异主要归因于其微观结构和成分的不同。由于ZrO 2薄膜与MPTS-SAM之间具有良好的粘附性，因此有望在微机电系统（MEMS）中受到小法向载荷滑动的单晶硅和碳化硅的表面保护中得到应用。
A silane coupling reagent (3-mercaptopropyl)trimethoxysilane (abridged as MPTS) was self-assembled on a single-crystal Si substrate to form a two-dimensional organic monolayer (MPTS-SAM). The terminal –SH group in the MPTS-SAM film wasin-situoxidized to –SO3H group to endow the film with good chemisorption ability. Then ZrO2thin films were deposited on the oxidized MPTS-SAM by way of the enhanced hydrolysis of aqueous zirconium sulfate (Zr(SO4)2·4H2O) in the presence of aqueous HCl at 50 °C, making use of the chemisorption ability of the –SO3H group. The thickness of the ZrO2films was determined with an ellipsometer, while their morphologies and corresponding friction forces were analyzed by means of atomic force microscopy. The hardness and elastic modulus of the ZrO2thin films were determined on a Nanoindentation II (MET) instrument. The macro-friction and wear behaviors of the ZrO2films sliding against an AISI-52100 steel ball were examined on a unidirectional friction and wear tester and the worn surface morphologies observed on a scanning electron microscope (SEM). As the results, the as-deposited ZrO2thin film at a deposition duration of 100 h is about 100 nm thick, it decreases to 48 nm after annealing at 500 °C and further decreases to 45 nm after heating at 800 °C. The as-deposited ZrO2film is relatively rougher, with the rms to be about 1.0 nm, while the ZrO2thin films heated at 500 and 800 °C have surface roughness rms of 0.76 nm and 0.68 nm, respectively. The ZrO2film annealed at 800 °C has a high hardness to elastic modulus (H/E) ratio (0.062) as compared to the as-deposited ZrO2film and the film annealed at 500 °C. Both the two annealed ZrO2films show excellent wear-resistance as they slide against AISI-52100 steel at a normal load below 2.0 N, while the one annealed at 800 °C has better wear-resistance. The differences in the friction and wear behaviors of the as-deposited ZrO2film, the ZrO2film annealed at 500 °C and that annealed at 800 °C are attributed to their different micro structures and compositions. Since the ZrO2films was well adhered to the underlying MPTS-SAM, it might find promising application in the surface-protection of single crystal Si and SiC subject to sliding at small normal load in microelectromechanical systems (MEMS).