TiN和Ti1-xSixNy薄膜的微观结构分析

使用x射线衍射(XRD)、x射线光电子谱(XPS)、高分辨透射电子显微镜(HRTEM)和原子力显微镜（AFM）多种观测手段分析了TiN薄膜和Ti_1-xSi_xN_y纳米复合薄膜的微观结构.实验分析证明Ti_1-xSi_xN_y薄膜是由直径为3—5nm的纳米晶TiN和非晶Si₃N₄相构成，并且Ti_1-xSi_{x关键词： 纳米复合薄膜 自由能 表面粗糙度 TiN 1-x}Si_xN_y')" href="#">Ti_1-xSi_xN_y     

TiN薄膜在纳米压痕和纳米划痕下的断裂行为

利用磁控溅射方法在Si(111)衬底上制备了具有(111)和(222)择优取向的TiN薄膜. 用纳米压痕和纳米划痕方法研究了该薄膜的变形和断裂行为. 用扫描电子显微镜、纳米压痕原位原子力显微镜及原位光学显微镜并结合加-卸载 曲线及划痕曲线获得了薄膜发生变形和断裂的微观信息. 在压痕试验中, TiN薄膜在压入深度为200 nm时表现为塑性变形及压痕周围的局部断裂, 随着压入深度的增大, 塑性变形和局部断裂变得越显著, 当最大压入深度达到临界值1000 nm时, 薄膜和衬底间发生了界面断裂. 在划痕实验中, 100 mN及200 mN的最大载荷均可以引起界面断裂. 最大为200 mN的载荷使得薄膜发生界面断裂的位置比用100 mN载荷时的位置提前, 但其临界断裂载荷和100 mN时及压痕实验时的临界界面断裂载荷基本相同. 关键词： TiN薄膜 纳米压痕 纳米划痕 界面断裂     

偏压对TiN／Ti薄膜组织、结构和性能的影响

过渡金属的氮化物硬质薄膜和一些氮化物多层薄膜被广泛应用于耐磨、抗腐蚀等方面。在这些氮化物中，TiN由于其优良的物理化学性能，在许多应用领域中占有重要的地位，同时具有很大的发展潜力和应用前景。电弧离子镀TiN镀层的制备工艺参数对薄膜的组织、结构有较大的影响，研究不同沉积参数对薄膜的组织、结构之间的内在关系，对优化沉积参数，提高薄膜的综合使用性能具有十分重要的作用。     

B掺杂对Ti薄膜结构与性能的影响

采用双靶共溅射方法制备了微量B掺杂的Ti薄膜样品, 利用X射线光电子能谱、扫描电子显微镜和X射线衍射仪对样品的掺杂原子浓度、 表面形貌、晶型结构、晶粒尺寸和应力进行了分析表征. 研究表明: 掺杂后的Ti薄膜晶粒得到明显细化, 并随着掺杂浓度的增大, 薄膜的晶粒尺寸呈减小趋势, 当掺杂浓度为5.50 at%时, Ti薄膜晶粒尺寸减小为1.3 nm, 呈现出致密的柱状结构. B掺杂后的Ti薄膜应力由压应力转变为张应力.     

Au/TiN复合薄膜制备及其表面增强拉曼光谱研究

表面增强拉曼散射光谱(SERS)已用于环境监测、生物医药、食品卫生等领域,而高活性SERS基底是表面增强拉曼散射光谱技术应用的关键。TiN作为新型等离子材料具有较强的SERS性能,同时化学稳定性及生物相容性较好,但其SERS性能不如贵金属金强。该研究采用氨气还原氮化法和电化学沉积法,在TiN薄膜表面沉积贵金属Au纳米颗粒制备出Au/TiN复合薄膜。在Au/TiN复合薄膜中单质Au和TiN两种物相共存;随着电化学沉积时间延长,TiN薄膜表面单质金纳米颗粒数量逐渐增多,金纳米颗粒尺寸增大,颗粒间距减小。由于金与TiN两者的本征表面等离子共振耦合作用,Au/TiN复合薄膜的共振吸收峰发生了偏移。利用罗丹明6G为拉曼探针分子,对Au/TiN复合薄膜进行SERS性能分析,发现Au/TiN复合薄膜上的R6G探针分子的拉曼峰信号强度随沉积时间延长呈现先增大后减小的规律;当电化学沉积时间为5 min时,R6G拉曼信号峰较高,复合薄膜样品的SERS活性最大。将Au/TiN复合薄膜和Au薄膜分别浸泡在10-3,10-5,10-7,10-8及10-9 mol·L-1 R6G溶液5 min,进行检测限分析,发现Au/TiN复合薄膜检测极限达10-8 mol·L-1,增强因子达到8.82×105,与Au薄膜和TiN薄膜相比,Au/TiN复合薄膜上对R6G探针分子SERS活性最高。这得益于Au/TiN复合膜中表面等离子体产生的耦合效应,使得局域电磁场强度增强,从而引起R6G探针分子拉曼信号增强。通过2D-FDTD模拟电场分布发现Au/TiN,Au及TiN薄膜具有电场增强作用,其中Au/TiN复合薄膜的增强作用尤为显著,这也证实了氮化钛与金纳米颗粒之间存在耦合效应。另外发现TiN与Au之间可能存在电荷转移,促进了4-氨基苯硫酚氧化反应,进而证实了TiN与Au薄膜的协同作用。此外,Au/TiN复合薄膜均匀性较好,相对平均偏差仅为7.58%。由此可见,采用电化学沉积制备的Au/TiN复合薄膜具有作为SERS基底材料的应用潜力。     

纳米晶Ti薄膜的结构研究

用高密度、高电离度的电子迴旋共振等离子体溅射方法在室温基片上沉积出纳米晶Ti薄膜,基体为玻璃、NaCl单晶、纯Al等。对Ti薄膜的结构、形貌和成分进行X射线衍射(XRD),透射电子显微镜(TEM)和X射线光电子能谱(XPS)分析,表明所沉积的Ti薄膜是平均粒径d<10nm,晶粒大小均匀且具有比较稳定的fcc反常结构的纳米晶粒膜。我们还较系统地研究了各工作参数对Ti薄膜的晶体结构、晶粒尺寸、成膜速率以及对基体粘附力的影响,分析了成膜机理。 关键词：     

Mo纳米薄膜热力学性质的分子动力学模拟

采用改进嵌入原子法(MAEAM),通过经典的分子动力学(MD)模拟计算了高熔点过渡金属体心立方(bcc) Mo块体Gibbs自由能和表面能. 对于纳米薄膜的热力学数据,比如Gibbs自由能等,可以看成是薄膜内部原子和表面原子两部分数据之和,然后根据薄膜的体表原子之比就可以直接计算出总的自由能,并由此可以得到热力学性质与薄膜尺寸及温度的定量关系式. 分别计算了bcc Mo块体及其纳米尺寸薄膜的自由能和热容,结果表明,Mo纳米薄膜的热力学性质具有尺寸效应,并且在薄膜尺寸小于15—20nm时,这种效应变得非常明 关键词： 改进嵌入原子法 Mo纳米薄膜 表面自由能 热容     

直流磁控溅射制备AlN薄膜的结构和表面粗糙度

采用直流磁控反应溅射法,在Si(111)基底上成功制备了多晶六方相AlN薄膜.研究了溅射过程中溅射气压对薄膜结构和表面粗糙度的影响.结果表明:当溅射气压低于0.6 Pa时,薄膜为非晶态,在傅里叶变换红外光谱中,没有明显的吸收峰;当溅射气压不低于0.6 Pa时,薄膜的X射线衍射图中均出现了六方相的AlN(100)、(110)和弱的(002)衍射峰,说明所制备的AlN薄膜为多晶态,在傅里叶变换红外光谱中,在波数为677 cm-1处有明显的吸收峰;随着溅射气压的增大,薄膜表面粗糙度先减小后增大,而薄膜的沉积速率先增大后减少,且沉积速率较大有利于减小薄膜的表面粗糙度;在溅射气压为0.6 Pa时,薄膜具有最小的表面粗糙度和最大的沉积速率.     

直流磁控溅射制备AlN薄膜的结构和表面粗糙度

采用直流磁控反应溅射法,在Si(111)基底上成功制备了多晶六方相AlN薄膜.研究了溅射过程中溅射气压对薄膜结构和表面粗糙度的影响.结果表明:当溅射气压低于0.6 Pa时,薄膜为非晶态,在傅里叶变换红外光谱中,没有明显的吸收峰;当溅射气压不低于0.6 Pa时,薄膜的X射线衍射图中均出现了六方相的AlN(100)、(11...     

Al(001)表面上沉积Ti薄膜的分子动力学模拟

采用分子动力学模拟方法,研究了Ti原子连续沉积于Al(001)表面上的薄膜生长过程,分析了入射能量为0.1、5 eV和衬底温度为300、700 K时的界面结合及微观结构.模拟结果表明,增加入射能量和衬底温度,使Ti薄膜的表面越光滑;通过径向分布函数和键对分析技术对薄膜微观结构进行分析,发现衬底温度时薄膜微观结构影响较大,温度300 K及以下时,Ti薄膜主要是FCC结构,随着温度升高,FCC结构成分减少,无序结构成分增加,而入射能量则对薄膜微观结构没有明显影响.     

溅射压强对TiN/SiNx纳米多层膜微观结构及力学性能的影响

利用磁控溅射方法在不同溅射压强条件下制备了TiN/SiN_x纳米多层膜.多层膜的微观结构及力学性能分别用X射线衍射仪、原子力显微镜及纳米压痕仪来表征.结果表明随着溅射压强的增大,多层膜的界面变模糊,TiN层的择优取向由(200)晶面过渡到(111)晶面.与此同时,多层膜的表面粗糙度增大,硬度和弹性模量随溅射压强的增大而减小.多层膜力学性能的差异主要是由于薄膜的周期性结构及致密度存在差异所致. 关键词： x多层膜')" href="#">TiN/SiN_x多层膜 界面宽度 表面形貌     

Effects of pulsed bias duty ratio on microstructure and mechanical properties of TiN/TiAlN multilayer coatings

TiN/TiAlN multilayer coatings were deposited on M2 high speed steel by a pulsed bias arc ion plating system. The effect of pulsed bias duty ratio on the microstructure, mechanical and wear properties was investigated. The amount of macroparticles reduced with the increase of the duty ratio. The surface roughness was 0.0858 μm at duty ratio of 50%. TiN/TiAlN multilayer coatings were crystallized with orientations in the (1 1 1), (2 0 0) (2 2 2) and (3 1 1) crystallographic planes and the microstructure strengthened at (1 1 1) preferred orientation. At duty ratio of 20%, the hardness of TiN/TiAlN multilayer coatings reached a maximum of 3004 HV, which was 3.2 times that of the substrate. The adhesion strength reached a maximum of 77 N at 50% duty ratio. Friction and wear analyses were carried out by pin-on-disc tester at room temperature. Compared with the substrate, all the specimens coated with TiN/TiAlN multilayer coatings exhibited better tribological properties.     

Chemistry and microstructure of PLD (Ti,Al)CxN1-x coatings deposited at room temperature

The aim of the present work was the improvement of titanium-aluminium nitride (TiAlN) coatings by the solid-solution hardening with carbon atoms leading to titanium-aluminium carbon-nitride (Ti,Al)C_xN_1-x coatings with varying carbon (x) and nitrogen contents. The request of low deposition temperatures necessary for the coating of heat sensitive materials like tool steels of high hardness and polymers was reached by the application of the room temperature pulsed laser deposition (PLD) technique. A Nd:YAG laser of 1064 nm wavelength operated at two different laser pulse energies was used in the ablation experiments of pure TiAl targets (50 at.% Al) in various C₂H₂-Ar gas mixtures. Different pulse energies of the laser resulted in changes of the ratio of Ti/Al atoms in the grown coatings. Furthermore, the results reveal a strong proportionality of the gas mixture to the C and N content of the coatings. In the coatings deposited at low C₂H₂ gas flows the XRD investigations showed crystalline phases with fcc TiN type lattices, whereas high acetylene flows during deposition resulted in the formation of fully amorphous coatings and carbon precipitation or cluster boundaries found in Raman investigations. PACS 81.15.Fg; 46.55.+d     

Microstructure and mechanical characteristics of hydroxyapatite coatings on Ti/TiN/Si substrates synthesized by pulsed laser deposition

We synthesized by pulsed laser deposition a bilayer of Ti/TiN on Si(100) wafers which was coated in a next step with hydroxyapatite (samples labelled HA-1). Some of the structures were further thermally treated in a water vapour jet (samples labelled HA-2). In SEM, the HA surface looked rough, with micronic droplets. TEM and SAED investigations revealed a compact organization of HA crystals in the case of the HA-1 sample, while two regions (one compact and one porous) were identified for the HA-2 sample, with triclinic HA crystals within the 500 nm range. In XTEM, at the Si/TiN border, a 2–3 nm SiO₂ layer was visible, whereas at the TiN/Ti border there was a smooth transition from fcc (111) TiN to hcp (100) Ti. The HA crystals were elongated normal to the surface. According to Berkovich indentation qualitative analyses, the sample HA-1 was more homogeneous and harder but brittle. Scratch tests confirmed quantitatively that HA-1 was more resistant and adherent than HA-2 films. In the first case, the big droplets only were removed by the indenter, while the HA-2 films were delaminated on large areas as a result of wedge spallation failure.     

Structural and mechanical properties of nano-crystal TiN coatings

The structural and mechanical properties of TiN coatings prepared by ion beam assisted deposition (IBAD) were studied. The coatings have a polycrystal structure with grain size of ≈10nm or less. The hardness of the coatings increases with increasing grain size of TiN crystallites. The coating with grain size of 10.3 nm even has a superhardness of 44.7 GPa. The relationship between the hardness and the grain size in the nano-crystalline coatings was discussed on the basis of grain-boundary triple junctions.

     

Laser ablation and micropatterning of thin TiN coatings

Laser ablation of thin TiN films deposited on steel substrates has been studied under wide-range variation of irradiation conditions (pulsewidth, wavelength, energy density and spot size). It has been demonstrated that both picosecond (150–300 ps) and nanosecond (5–9 ns) laser pulses were suitable for controllable ablation and microstructuring of a 1-μm-thick TiN film unlike longer 150-ns pulses. The ablation rate was found to be practically independent of the wavelength (270–1078 nm) and pulsewidth (150 ps–9 ns), but it increased substantially when the size of a laser spot was reduced from 15–60 μm to 3 μm. The laser ablation technique was applied to produce microstructures in the thin TiN films consisting of microcraters with a typical size of 3–5 μm in diameter and depth less than 1 μm. Tests of lubricated sliding of the laser-structured TiN films against a steel ball showed that the durability of lubricated sliding increased by 25% as compared to that of the original TiN film. Received: 28 July 1999 / Accepted: 17 April 2000 / Published online: 20 September 2000     

Structural and mechanical properties of nano-crystal TiN coatings

The structural and mechanical properties of TiN coatings prepared by ion beam assisted deposition (IBAD) were studied. The coatings have a polycrystal structure with grain size of ～10 nm or less. The hardness of the coatings increases with increasing grain size of TiN crystallites. The coating with grain size of 10.3 nm even has a superhardness of 44.7GPa. The relationship between the hardness and the grain size in the nano-crystalline coatings was discussed on the basis of grain-boundary triple junctions.     

The effect of heat treatment on the electrochemical corrosion behavior of reactive plasma-sprayed TiN coatings

The effect of heat treatment on the corrosion behavior of reactive plasma sprayed TiN coatings in simulated seawater was investigated by electrochemical methods such as the corrosion potential-time curve (E_corr − t), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and SEM, etc. The results showed that the corrosion potential of TiN coatings increased after heat treatment; the corrosion current of the TiN coatings after heat treatment (be hereafter referred to as HT-TiN) was 13.3% of the untreated coatings (be hereafter referred to as UT-TiN), and the polarization resistance of HT-TiN was 20 times of UT-TiN, which indicated that the heat treatment had significantly increased the corrosion resistance of the coatings. The corrosion behavior of the coatings was mainly local corrosion, and the local corrosion behavior mainly took place at the microdefects (crack and pores) of the coatings. The porosity of the coatings was reduced after heat treatment. The reason was that TiN reacted with O₂ to form TiO₂ and Ti₃O during the heat treating, and volume expansion took place, which led to denser microstructure. The corrosion resistance of the coatings was therefore increased.