铜合金表面Ti/TiN多层膜的制备、结构及其性能

为了研究多层膜的腐蚀性能,促进多层膜在生产中的应用,采用电弧离子镀技术,通过调整环境N₂和Ar气的时间比例在铜衬底上成功制备了不同调制周期的Ti/TiN多层膜.利用x 射线衍射谱和交流阻抗谱研究了该多层膜的结构和腐蚀性能.表面形貌显示,沉积的Ti/TiN多层膜具有明显的周期性,环境中N2和Ar气的时间比例决定了多层膜的调制周期,N₂气时间越长,多层膜中TiN相层越厚.腐蚀性能测定表明,多层膜的调制周期影响其耐蚀性,当调制周期为550nm时,沉积膜的耐腐蚀性最好.     

Effects of N<Subscript>2</Subscript> pressure on the structural and electrical properties of tin films deposited by laser molecular beam epitaxy

Titanium nitride (TiN) films were deposited on Si(100) substrates by laser molecular beam epitaxy(LMBE), and their properties of structure and resistivity with varying N₂ pressure were investigated. The results showed that atomically flat TiN films with layer-by-layer growth mode were successfully grown on Si(100) substrates, and (200) was the preferred orientation. With the increasing of N₂ pressure, the N/Ti ratio gradually increased and the diffraction peak progressively shifted towards lower diffraction angle. At pressure of 0.1 Pa, stoichiometric TiN film was formed which exhibited the characteristic diffraction angle of (200) plane. All films showed high reflectance to infrared spectrum and the films with overstoichiometry and understoichiometry had a higher resistivity owing to the surface particles and lattice distortion, while the stoichiometric TiN film depicted the minimum resistivity, around 19 μΩ·cm.     

Load Dependence of Nanohardness in Nitrogen Ion Implanted Ti6AI4V Alloy and Fractal Characterization

Three different nitrogen ion doses were implanted into a Ti6A14V alloy to improve its mechanical surface properties for the application of artificial joints. The titanium nitride phase and nitrogen element distribution profile were characterized with X-ray photoelectron spectroscopy （XPS）. Nano-indentation tests were carried out on the surface of the Ti6A14V alloy and implanted samples on a large scale of applied loads. The XPS analysis results indicate that nitrogen diffuses into the titanium alloy and forms a hard TiN layer on the Ti6A14V alloy. The nanohardness results reveal that nitrogen ion implantation effectively enhances the surface hardness of Ti6A14V. In addition, the nanohardness clearly reveals load dependence over a large segment of the applied loads. Thus a concept of nanohardness fractal dimension is first proposed and the dual fractal model can effectively describe nonlinear deformation in indentation areas on the Ti6A14V surface. The fractal dimension shows a decreased trend in two regions of applied loads, indicating a decrease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.     

Load Dependence of Nanohardness in Nitrogen Ion Implanted Ti6Al4V Alloy and Fractal Characterization

Three different nitrogen ion doses were implanted into a Ti6Al4V alloy to improve its mechanical surface properties for the application of artificial joints. The titanium nitride phase and nitrogen element distribution profile were characterized with X-ray photoelectron spectroscopy (XPS). Nano-indentation tests were carried out on the surface of the Ti6Al4V alloy and implanted samples on a large scale of applied loads. The XPS analysis results indicate that nitrogen diffuses into the titanium alloy and forms a hard TiN layer on the Ti6Al4V alloy. The nanohardness results reveal that nitrogen ion implantation effectively enhances the surface hardness of Ti6Al4V. In addition, the nanohardness clearly reveals load dependence over a large segment of the applied loads. Thus a concept of nanohardness fractal dimension is first proposed and the dual fractal model can effectively describe nonlinear deformation in indentation areas on the Ti6Al4V surface. The fractal dimension shows a decreased trend in two regions of applied loads, indicating a decrease of the self-similarity complexity in surface indentation owing to an increase in nanohardness after nitrogen ion implantation.     

Interfacial microstructure and properties of Ti(C,N)/Ni bonded by transient liquid-phase diffusion

Effects of the main process parameters(temperature and time) on microstructure and properties of Ti(C, N)/Ni interface bonded by (Cu+Nb) interlayer in a vacuum diffusion bonding device were investigated. The interfacial microstructures consisted initially of Ni₃Nb metallic compound and eutectic of Ni₃Nb+CuNi_SS, and finally transformed to (Ti, Nb) (C, N)+Ni₃Nb near Ti (C, N) and NiCu_SS+Ni₃Nb near Ni when diffusion bonding temperature was 1 523–1 573 K. It was clear that Cu was a constituent in the transient liquid phase (TLP) into which Ni was dissolved by forming Cu-Ni transition liquid. Nb was dissolved in Cu-Ni transition liquid rapidly. Ti (C, N) conld be wetted by resultant Ni-Nb-Cu transient liquid phase which was followed by a little (Ti, Nb) (C, N) solid solution formed at interface. This increased the interface combining capability. Ultimately the interface shear strength was able to reach 140 MPa. The theoretle analysis and experimental results show that the growth of interfacial reaction layer Ni₃Nb accords with parabola law, and the activation energy of diffusion reaction is 115.0±0.5 kJ/mol, while the diffusion reaction speed constant is 12.53 mm/s^1/2. Funded by the National Natural Science Foundation of China (No. 50074017/E0408)     

直流PCVD法钛化合物的研究

用直流等离子体化学气相沉积法沉积TiC、TiN、Ti(CN)以及钛的复合涂层。对在高速钢和硅基体上所得的各种钛化合物膜做了晶体结构分析、表面形貌分析、断口结构分析和显微硬度分析等。试验表明:在沉积温度600℃左右,所得的多种Ti(CN)涂层有很高的显微硬度和良好的粘接力。这些涂层有的是由TiC和TiN两种晶体组成,有的是由TiC、TiN和Ti(CN)三种晶体组成。部分Ti(CN)的结构非常细密,是由多种晶体组成的混合物。     

多层复合TiN镀层的研究进展

TiN镀层已获得广泛的应用.为克服单一TiN镀层的不足和进一步改善TiN镀层的性能,近年来,对TiN镀层进行了深入的研究.本文综述了多层复合TiN镀层研究的最新进展,详述了TiN/氮化、TiN/Ni-P、TiN/TaN、TiN/SiC、TiN/TiCrN/CrN/CrTiN、Ti(C,N)/TiN、TiN-MoS2/Ti、TiN-DLC多层复合镀层的工艺、结构和性能,指出了今后TiN镀层的研究方向.     

Precipitation characteristic of high strength steels microalloyed with titanium produced by compact strip production

Transmission electron microscopy (TEM) and physics-chemical phase analysis were employed to investigate the precipitates in high strength steels microalloyed with Ti produced by compact strip production (CSP). It was seen that precipitates in Ti microalloyed steels mainly included TiN, Ti4C2S2, and TiC. The size of TiN particles varied from 50 to 500 nm, and they could precipitate during or before soaking. The Ti4C2S2 with the size of 40-100 nm might precipitate before rolling, and the TiC particles with the size of 5-50 nm precipitated heterogeneously. High Ti content would lead to the presence of bigger TiC particles that precipitated in austenite, and by contrast, TiC particles that precipitated in ferrite and the transformation of austenite to ferrite was smaller. They were less than 30 nm and mainly responsible for precipitate strengthening. It should be noted that the TiC particles in higher Ti content were generally smaller than those in the steel with a lower Ti content.     

Chemieal Bonding States of TiC Films before and after Hydrogen Ion Irradiation

TiC films deposited by rf magnetron sputtering followed by Ar＋ ion bombardment were irradiated with a hydrogen ion beam. X-ray photoelectron spectroscopy （XPS） was used for characterization of the chemical bonding states of C and Ti elements of the TiC films before and after hydrogen ion irradiation, in order to understand the effect of hydrogen ion irradiation on the films and to study the mechanism of hydrogen resistance of TiC films. Conclusions can be drawn that ion bombardment at moderate energy can cause preferential physical sputtering of carbon atoms from the surface of low atomic number （Z） material. This means that ion beam bombardment leads to the formation of a non-stoichiometric composition of TiC on the surface. TiC films prepared by ion beam mixing have the more excellent characteristic of hydrogen resistance. One important cause, in addition tO TiC itself, is that there are many vacant sites in TiC created by ion beam mixing. These defects can easily trap hydrogen and effectively enhance the effect of hydrogen resistance.     

Effect of tin on the reaction synthesis of ternary carbide Ti3AlC2

The effect of tin on synthesis of Ti₃AlC₂ by spark plasma sintering (SPS) from TiC/Ti/Al powders was investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for phase identification and microstructure evaluation. The experimental results show that addition of tin can considerably accelerate the synthesis reaction of Ti₃AlC₂ and fully dense, essentially single-phase polycrystalline Ti₃AlC₂ could be successfully obtained by sintering 2TiC/1Ti/1Al/0.2Sn powders at 1200–1250 °C under a pressure of 30 MPa. SEM images show that Ti₃AlC₂ samples in about 2–5 μm thick and 10–25 μm long platelets can be obtained. The fracture toughness and flexural strength of Ti₃AlC₂ were 6.5±0.2 MPa·m^1/2 and 560±10 MPa, respectively. Funded by the National Natural Science Foundation of China (No.20771088, No.50572080) and Doctoral Foundation of Wuhan University of Technology (No.471-38650142)     

钛在铁水中的行为

由热力学计算结果分析了高炉冶炼含ＴｉＯ２铁矿时钛的物理化学行为,指出：有固体碳存在果,渣界面不能有纯ＴｉＮ生成,应该析出Ｔｉ（Ｃ３Ｎ）固溶体,     

高炉炉缸形成Ti(C,N)粘结层的实验室模拟

在实验室条件下,模拟高炉冶炼钒钛磁铁矿时炉缸处Ti(C,N)粘结层生成过程.通过热力学分析,反应在试验条件下可以进行.TiC、TiN生成的起始温度分别为1467K和1408K.采用金相显微镜、SEM和XRD等对试验坩埚中渣-石墨边界层进行分析.结果得到,反应随恒温时间的延长Ti(C,N)粘结层增厚并趋于复杂化,形成由渣、铁、Ti(C,N)以及碳颗粒组成的混合层.其中,Ti(C,N)以点散状分布.     

几种氧化铝基陶瓷材料的摩擦特性及有限元分析

利用高速环-块摩擦磨损试验机,研究了Al2O3、Al2O3/Ti(C,N)、Al2O3/TiC/CaF2陶瓷材料在室温下与45#钢干摩擦时的摩擦特性,并利用ANSYS分析了摩擦过程中的应力分布。结果表明:纯Al2O3和Al2O3/Ti(C,N)随着转速和载荷(载荷为10 N除外)的增加摩擦系数呈下降趋势;Al2O3/TiC/CaF2的摩擦系数先随转速增大而略有上升,然后减小,随着载荷(载荷为10 N除外)的增加摩擦系数减小。与Al2O3相比,Al2O3/Ti-(C,N)陶瓷的最大主应力和最大剪应力接近,但力学性能优于Al2O3陶瓷,使磨粒的刻划作用减弱,摩擦磨损性能改善;Al2O3/TiC/CaF2自润滑陶瓷的主应力和剪应力明显降低,并且在摩擦过程中自润滑陶瓷能在摩擦表面形成一层自润滑膜,从而改善了摩擦磨损性能。     

离子镀（Ti,Cr）N涂层的组织结构与耐蚀性能的研究

研究了离子镀（Ｔｉ,Ｃｒ）Ｎ涂层的组织结构和耐蚀性,经ＸＲＤ分析表明,（Ｔｉ,Ｃｒ）Ｎ涂层中的Ｃｒ原子部分置换ＴｉＮ晶格中的Ｔｉ原子,且部分与Ｎ反应生成ＣｒＮ,Ｃｒ２Ｎ或以单质态存在。经耐蚀性分析得知,由于Ｃｒ的加入,提高了（Ｔｉ,Ｃｒ）Ｎ涂层的致密度,同时加剧了阴极极化程度,延长了腐蚀原电池的开动过程,从而增强了涂层的耐蚀性。     

Electron Spectroscopy Studies on SiC Films before and after Hydrogen Ion Irradiation

1Introduction Theinteractionbetweenenergetichydrogenandlow Zmaterials,suchasSiC,hasbeenstudiedinseveral groupsbecausecarbidesoflowZelementsareusedfor plasmafacingcomponentsasfirstwallmaterialsin Tokamak[1,2].Hence,itisofinteresttounderstandthe effectsofHp…     

Effect of interface layers on electron field emission properties of amorphous diamond films

Hydrogen-free high sp~3 content amorphous diamond (AD) films are deposited on three different substrates——Au-coated Si (Au/Si), Ti-coated Si (Ti/Si) and Si wafers. Electron field emission properties and fluorescent displays of the above AD films are studied by using a sample diode structure. The compositional profile of the interfaces of AD/Ti/Si and AD/Si is examined by using secondary ions mass spectroscopy (SIMS). Because of the reaction and interdiffusion between Ti and C, the formation of a thin TiC intermediate layer is possible between AD film and Ti/Si substrate. The field emission properties of AD/Ti/Si are sufficiently improved, especially its uniformity. A field emission density of 0.352 mA/cm~2 is obtained under an electric field of 19.7 V/μm. The value is much more than that of AD/Au/Si and AD/Si under the same electric field.     

Nano-phases and corrosion resistance of C+Mo dual implanted steel

The corrosion resistance of C + Mo dual-implanted HI3 steel was studied using multi-sweep cyclic voltammetry. The phase formation conditions for corrosion resistance and its effects were researched. The super-saturation solid station solution of Mo+ and C+ atoms was formed in Mo + C dual implanted steel. Precipitate phase with nanometer size Fe2Mo, FeMo, MoC, Fe5C3 and Fe7C3 were formed in dual implanted layer. The passivation layer consisted of these nanometer phases. The corrosion resistance of the dual implanted layer was better than that of single Mo implantation. Jp of the Mo implanted sample is 0.55 times that of H13 steel. The corrosion resistance of the dual implantation was enhanced when ion dose increased. When the Mo+ ion dose was 6 × 1017/cm2 in the dual implantation, Jp of the dual implanted sample was only 0.11 times that in H13 steel. What is important is that pitting corrosion properties of dual implanted steel were improved obviously.     

等离子化学气相沉积硬膜技术研究

用等离子体化学气相沉积（ＰＣＶＤ）技术制备了ＴＩＮ、ＴｉＣ、Ｔｉ（ＣＮ）和（ＴｉＳｉ）Ｎ膜及其组合的多层膜。ＰＣＶＤ具有很好的覆盖性，ＰＣＶＤ－ＴｉＮ具有很好的耐磨、蚀性，膜与基体结合良好，因而用ＰＣＶＤ法在高速钢刀具、模具及轴承上沉积ＴｉＮ可大大提高其使用寿命。ＰＣＶＤ－ＴｉＮ和Ｔｉ（ＣＮ）膜无明显柱状晶，其显微硬度高于ＴｉＮ亦可用于高速钢刀具、模具上提高其使用寿命。ＰＣＶＤ－（ＴｉＳｉ）Ｎ，晶粒细化，氯含量和显微硬度随Ｓｉ含量而变化，（ＴｉＳｉ）Ｎ具有很好的抗高温氧化性。多层膜可调节膜层结构，减少残余应力，提高膜的机械性能。     

Microstructure and mechanical properties of an in situ synthesized TiB and TiC reinforced titanium matrix composite coating

A titanium-based composite coating reinforced by in situ synthesized TiB and TiC particles was fabricated on Ti6Al4V by laser cladding. The microstructure and mechanical properties were investigated. The coating was mainly composed of β-Ti cellular dendrites and an eutectic in which a large number of rod/needle-shaped TiB and a few equiaxial TiC particles were homogeneously embedded. The microstructural evolution could be divided into four stages: precipitation and growth of primary β-Ti phase, formation of the binary eutectic β-Ti+TiB, formation of the ternary eutectic β-Ti+TiB+TiC, and solid transformation from β-Ti to β-Ti. Microhardness of the coating showed a gradient variation from the surface (about HV0.2 876) to the bottom (about HV0.2 660) and was prominently improved in comparison with that of the substrate. Fracture toughness of the coating also exhibited a gradient variation from the surface (6.3 MPa·m1/2) to the interface (11.9 MPa·m1/2). Wear resistance of the coating was significantly superior to that of Ti6Al4V.     

Self-propagating high-temperature synthesis of (W, Ti) C powders

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