SHS等离子喷涂制备FeAl2O4-Al2O3-Fe纳米复合涂层的研究

利用SHS等离子喷涂技术，将经过机械团聚法制备的Fe₂O₃-Al复合粉体送入等离子焰流，沉积出厚度约为400 μm的复合涂层.利用XRD，SEM 和TEM等检测手段对涂层的成分和组织进行了分析，测定了涂层的显微硬度、断裂韧性以及耐磨性.结果表明涂层为具有纳米结构的FeAl₂O₄-Al₂O₃-Fe纳米复合组织；涂层的显微硬度为HV_100g870；断裂韧性是普通Al₂O₃涂层的2倍；无润滑磨损的耐磨性是普通Al₂O₃涂层的2.5倍. 关键词： SHS等离子喷涂 纳米涂层 断裂韧性     

SHS等离子喷涂制备FeAl2O4-Al2O3-Fe纳米复合涂层的研究

利用SHS等离子喷涂技术,将经过机械团聚法制备的Fe2O3-Al复合粉体送入等离子焰流,沉积出厚度约为400 μm的复合涂层.利用XRD,SEM 和TEM等检测手段对涂层的成分和组织进行了分析,测定了涂层的显微硬度、断裂韧性以及耐磨性.结果表明涂层为具有纳米结构的FeAl2O4-Al2O3-Fe纳米复合组织;涂层的显微硬度为HV100g870;断裂韧性是普通Al2O3涂层的2倍;无润滑磨损的耐磨性是普通Al2O3涂层的2.5倍.     

TaN/TiN和NbN/TiN纳米结构多层膜超硬效应及超硬机理研究

采用射频磁控溅射方法制备单层TaN,NbN和TiN薄膜和不同调制周期的TaN/TiN和NbN/TiN纳米多层膜.薄膜采用X射线衍射仪、高分辨率透射电子显微镜和显微硬度仪进行表征.结果表明TaN/TiN和NbN/TiN纳米多层膜在一定的调制周期范围内均呈共格界面,相应地均出现了超硬效应,且最大硬度值接近.分析了TaN/TiN与NbN/TiN纳米多层膜的超硬机理,TaN/TiN的晶格错配度与NbN/TiN的接近,但TaN/TiN的弹性模量差与NbN/TiN的有一定的差别,表明由于晶格错配使共格外延生长在界面处 关键词： TaN/TiN纳米多层膜 NbN/TiN纳米多层膜 外延生长 超硬效应     

ZrO2纳米粉等离子喷涂层组织与性能

用纳米结构粉末做喂料进行喷涂，缩短了颗粒熔化时间，在有限的飞行时间内，颗粒熔化效果更好，从而制备的涂层孔隙率更小，表面更平整。用ZrO2纳米结构喂料制备了等离子喷涂层，研究了功率、粒度、氧化钇含量等工艺参数条件下涂层的微观组织、孔隙率、相组成及抗热震性能。经X衍射分析表明，原始粉末由m-ZrO2,t-ZrO2,c-ZrO2构成，单斜相的含量为11％，主要由四方相和立方相构成。     

界面和择优取向对TiN/ZrN纳米多层膜硬度变化的影响

利用射频反应磁控溅射方法，制备了调制比约为4，调制周期不同的一系列TiN/ZrN纳米多层膜. 利用X射线衍射仪(XRD)、高分辨电子显微镜(HRTEM)和纳米压痕仪(Nanoindentation)对多层膜的调制结构、界面状态和力学性能进行了表征. 研究结果表明TiN/ZrN多层膜具有很好的调制结构，但是在TiN层和ZrN层之间存在一定厚度的界面混合层. 力学性能分析表明：当调制周期小于15 nm时，TiN/ZrN多层膜的硬度介于单一TiN和ZrN薄膜的硬度之间；当调制周期为15.24 nm时，硬度达到最大，但随着调制周期增加，多层膜的硬度基本上保持为常数. 分析了TiN/ZrN多层膜硬度变化的机制，认为界面厚度和择优取向是导致硬度变化的主要原因. 关键词： TiN/ZrN多层膜 界面宽度 择优取向 硬度变化     

金属管件内壁栅极增强等离子体源离子注入的轴向特性研究

栅极增强等离子体源离子注入(GEPSII)一种新的金属管件内壁处理方法，该方法能够均匀地对金属管件内壁进行离子注入，并且能够生成二元金属化合物.在金属管件内轴向放置三块45号钢样品，利用GEPSII方法在金属管件内壁成功生长金黄色氮化钛(TiN)薄膜.结构分析显示TiN主要沿(111)和(200)晶面生长，深度分析显示膜的厚度大约二十几纳米，膜质地均匀且在基底有一定的嵌入深度.电化学腐蚀、硬度、磨擦学分析表明TiN薄膜很好地改善了45号钢的表面性能，并且表现出很高的轴向均匀性. 关键词： 等离子体源离子注入 内表面 氮化钛     

TiN/SiC纳米多层膜的生长结构与力学性能

研究了TiN/SiC纳米多层膜中立方SiC（B1cubic SiC）的形成及其对TiN/SiC多层膜力学性能的影响.结果表明：在TiN/SiC多层膜中，非晶态的SiC层在厚度小于0.6nm时形成立方结构并与TiN形成共格外延生长的超晶格柱状晶，使多层膜产生硬度和弹性模量显著升高的超硬效应，最高硬度超过60GPa.SiC随着层厚的增加转变为非晶相，从而阻止了多层膜的共格外延生长，使薄膜呈现TiN纳米晶和SiC非晶组成的层状结构特征，同时多层膜的硬度和弹性模量下降.TiN/SiC纳米多层膜产生的超硬效应与立方 关键词： 立方碳化硅 TiN/SiC纳米多层膜 外延生长 超硬效应     

TiN/SiO2纳米多层膜的晶体生长与超硬效应

高硬度的含氧化物纳米多层膜在工具涂层上具有重要的应用价值.研究了TiN/SiO2纳米多层膜的晶体生长特征和超硬效应.一系列具有不同SiO2和TiN调制层厚的纳米多层膜采用多靶磁控溅射法制备;采用x射线衍射、x射线能量色散谱、高分辨电子显微镜和微力学探针表征了多层膜的微结构和力学性能.结果表明,虽然以单层膜形式存在的TiN和SiO2分别形成纳米晶和非晶结构,它们组成多层膜时会因晶体生长的互促效应而呈现共格外延生长的结构特征.在SiO2调制层厚度约小于1 nm时,多层膜呈现强烈的(111)织构,并伴随着硬度和弹性模量的显著上升,最高硬度和弹性模量分别达到44.5和473 GPa.进一步增加SiO2层的厚度,由于SiO2层呈现非晶态,多层膜的共格外延生长受到抑制,硬度也相应降低.TiN调制层厚度的改变虽对多层膜的生长结构和力学性能也有影响,但并不明显.     

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。     

内表面栅极等离子体源离子注入TiN薄膜及其特性研究

阐述了栅极增强等离子体源离子注入（GEPSII）方法的基本思想.利用GEPSII方法在45号钢 基底上生成了金黄色氮化钛（TiN_x）膜.对不同条件下的TiN膜做电化学腐蚀，X PS，AES， XRD等分析.电化学腐蚀实验显示TiN薄膜改善了45号钢的耐腐蚀性能5—10倍，且在高气压下 效果更好.结构分析显示TiN膜含有TiO₂，TiN成分，主要沿（111）和（200）晶 向生长，深度分析显示膜的厚度只有二十几纳米，膜质地均匀且在基底有一定的嵌入深度. 关键词： 腐蚀 等离子体源离子注入 薄膜 氮化钛     

The effect of powder preparation method on the corrosion and mechanical properties of TiN-based coatings by reactive plasma spraying

TiN-based composite coatings with and without the addition of Cr were deposited by reactive plasma spraying (RPS) in air. Both sintered and mixed powder of Ti and B₄C were used for the RPS process. A thermodynamic model was firstly used to estimate the complicated phase composition of composite coatings prepared by RPS. The phase composition, structures and properties of TiN-based coatings were investigated using XRD, SEM and a Vickers microhardness tester. The results show that the phases in TiN-based coatings do not generate according to priority of Gibbs free energy value due to non-equilibrium reactive course during thermal spraying. The coating deposited using sintered Ti and B₄C powder is composed of two main phases (TiN and TiN_0.3), two minor phases (Ti₂O₃ and TiB₂), and a small fraction of TiC phase. The composition of the coating deposited using the mixed powder with Cr added is predominantly in the TiN and TiB₂ phases, a smaller phase fraction of Ti₂O₃ and TiO₂, and some unreacted Cr. The Vickers microhardness of the coating deposited using sintered powder is higher than that of using mixed powder. The composite coating deposited using mixed powder with the addition of Cr shows superior corrosion resistant to that using sintered powder when tested in 3.5 wt.% NaCl electrolytic solution.     

Investigation of the microstructure and tribological behavior of cold-sprayed tin-bronze-based composite coatings

In this paper, tin-bronze/TiN and tin-bronze/quasicrystal (AlCuFeB) composite coatings were fabricated by cold spray process. Microstructure and microhardness of the prepared coatings were investigated. Ball-on-disc dry sliding wear tests were conducted in an ambient condition to examine the tribological behavior of the composite coatings. The results show that the microhardness and the density of composite coatings increase significantly compared to the pure tin-bronze coating. The friction coefficient of composite coating decreases when reinforcing particles were introduced. Furthermore, the bronze/quasicrystal composite coating has a lower friction coefficient and wear rate than the bronze/TiN coating. Tribological mechanisms of the composite coatings were discussed.     

Texturing in a Ni–W/TiN Thin-Film System

Double-layer thin-film compositions with a TiN coating based on a ferromagnetic Ni–5 at % W alloy and a paramagnetic Ni–9.5 at % W alloy have been prepared. Texturing in both components of the Ni–W/TiN system has been studied using X-ray diffraction analysis. It has been found that the coating layer causes crystal planes in the Ni–9.5 at % W strip to reorient and thereby enhances the cube texture in the substrate. It has been shown that under certain growth conditions, a thin TiN coating above the Ni–9.5 at % W/TiN substrate grows quasi-single-crystalline with a cube texture.     

Synthesis and microstructure observation of titanium carbonitride nanostructured coatings using reactive plasma spraying in atmosphere

In the present study, nanostructured titanium carbonitride (TiCN) coatings were successfully deposited by reactive plasma spraying (RPS) technology using a self-designed gas tunnel mounted on a normal plasma spray torch. The phase composition and microstructure of the TiCN coatings were characterised by XRD, SEM and TEM. The results indicated that the main phase of the coatings was FCC TiC_0.2N_0.8 with a small amount of Ti₃O. The coating that was deposited using 35 kW displayed better microstructure and properties. The coating exhibited a typical nanostructure including 90 nm diamertrical equiaxed grains and 400 nm long columnar grains by TEM images. The SEM observation further revealed that the equiaxed grains in parallel direction to the substrate surface in TEM images were actually the columnar grains perpendicular to the substrate surface. The formation mechanism of the nanostructured coatings was also discussed. The measured microhardness value of the coating was approximately 1659 Hv_100 g, and the calculated crack extension force was about 34.9 J/m².     

CEMS of nitride coatings in agressive environments

The corrosion properties of single layered TiN and CrN films have been compared to bi-layered and multi-layered Ti/TiN films. XPS has showed that in humid SO₂ atmosphere the best corrosion properties have been achieved by a multi-layered Ti/TiN coating. Cyclic voltammetry in acetate buffer has been applied to measure the porousity and corrosion resistance of coatings. The best results have been achieved by multi-layered Ti/TiN and CrN films. Conversion electron Mössbauer spectroscopy has been used to study the changes in the interface Fe/TiN during thermal treatment in UHV. It has been shown that the amount of iron nitrides in the interface increases with increasing temperature.     

Comparative study of titanium carbide and nitride coatings grown by cathodic vacuum arc technique

Titanium nitride (TiN), titanium carbide (TiC) thin films and TiC/TiN bilayers have been deposited on AISI 304 stainless steel substrates by plasma assisted physical vapor deposition technique—reactive pulsed vacuum arc method. The coatings were characterized in terms of crystalline structure, microstructure and chemical nature by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. Tribological behavior was investigated using ball on disc technique. The average coefficient of friction was measured, showing lower values for the TiN/TiC bilayer. Dynamic wear curves were performed for each coating, observing a better wear resistance for TiN/TiC bilayers, compared to TiN and TiC monolayers. On the other hand, the TiCN formation in the TiN/TiC bilayer was observed, being attributed to the interdiffusion between TiN and TiC at the interface. Moreover, the substrate temperature influence was analysing observing a good behavior at T_S = 115 °C.     

In-situ SEM indentation studies of the deformation mechanisms in TiN, CrN and TiN/CrN

In this study, the microstructure and the deformation mechanisms of TiN, CrN and multilayer TiN/CrN thin films on silicon substrates were investigated. Cross-sectional lamellas of nanoindents were prepared by focused ion beam milling to observe by transmission electron microscopy the microstructure of the as-deposited and deformed materials. TiN film exhibits nanocrystalline columns, whereas CrN shows large grains. The TiN/CrN multilayer presents microstructural features typical for both materials. A film hardness of 16.9GPa for CrN, 15.8GPa for TiN and 16.6GPa for TiN/CrN was found by the nanoindentation. Reduced modulus recorded for TiN and CrN reference coatings were 221.54 and 171.1GPa, respectively, and 218.6GPa for the multilayer coating. The deformation mechanisms were observed via in-situ scanning electron microscope nanoindentation. The TiN thin film showed short radial cracks, whereas CrN deformed through pile-up and densification of the material. For TiN/CrN multilayer pile-up and cracks were found. Transmission electron microscopy observations indicated that TiN deforms through grain boundary sliding and CrN via densification and material flow. The deformation mechanism observed in TiN/CrN multilayer was found to be a mixture of both modes.     

Optimization of plasma parameters for high rate deposition of titanium nitride films as protective coating on bell-metal by reactive sputtering in cylindrical magnetron device

Nano-structured titanium nitride (TiN) thin film coating is deposited by reactive sputtering in cylindrical magnetron device in argon and nitrogen gas mixtures at low temperature. This method of deposition using DC cylindrical magnetron configuration provides high uniform yield of film coating over large substrate area of different shapes desirous for various technological applications. The influence of nitrogen gas on the properties of TiN thin film as suitable surface protective coating on bell-metal has been studied. Structural morphological study of the deposited thin film carried out by employing X-ray diffraction exhibits a strong (2 0 0) lattice texture corresponding to TiN in single phase. The surface morphology of the film coating is studied using scanning electron microscope and atomic force microscope techniques. The optimized condition for the deposition of good quality TiN film coating is found to be at Ar:N₂ gas partial pressure ratio of 1:1. This coating of TiN serves a dual purpose of providing an anti-corrosive and hard protective layer over the bell-metal surface which is used for various commercial applications. The TiN film's radiant golden colour at proper deposition condition makes it a very suitable candidate for decorative applications.     

Influence of laser treatment on the corrosion properties of plasma-sprayed Ni-coated WC coatings

The electrochemical corrosion of plasma spray Ni-coated WC cermet coatings, after laser treatment, has been studied in 3.5% NaCl solution through immersion test. The main corrosion mechanism for as-sprayed coating is the galvanic corrosion between coating and substrate, resulting in the detachment of coating from substrate, while the homogeneous corrosion occurs for the laser treatment coating. However, the corrosion trace for the as-sprayed pure coating could not be found. It is found that the electrochemical corrosion has been found heavily depending on the galvanic corrosion between the coating and the substrate. The defects, such as pores and laminar structures in the coating, could act as the infiltration paths of the electrolyte.     

碳化钛及其复合涂层材料抗氚渗透层的稳定性

研究了３１６Ｌ不锈钢表面镀ＴｉＣ和ＴｉＮ＋ＴｉＣ复合涂层材料的抗氚透层在聚变环境中的稳定性。研究结果表明,ＴｉＣ和ＴｉＮ＋ＴｉＣ复合涂层材料经化学热处理后在其表面层生成的抗氚渗透层能抗Ｈ＾＋离子辐照,能抗很大的温度梯度和热循环,经长时间实验证明这些涂层材料的抗氚渗透层性能稳定。