T8钢－聚有机硅氧烷仿生减粘降阻复合涂层的特性

研究了Ｔ８钢－聚有机硅氧烷仿生减粘降阻复合涂层的表面润湿性、磨料磨损特性及对土壤的减粘降阻性能与金属材料相比，仿生复合涂层的表面憎水性显著提高，水在其表面上的接触角达９２°；与４５钢相比，其磨料磨损的体积相对耐磨系数为６３％，降阻率达１５．２２％～２２．２７％     

土壤动物体表及仿生复合涂层的润湿性

用电镜观察了土壤动物的典型体有形态，从理论上分析了土壤动物非光体表能降低体表润湿性及减少土壤粘附的机制，据此研制的触土部件仿生复合涂层，在磨料磨损条件下能有 形成类似于土壤动物体表非光滑形态，使其表面润润性明显降低，具有粘降阻的功能。     

钎焊工艺对WC—Co／NiCrBSi复合涂层性能的影响

采用真空钎焊技术,在４５＾＃钢基体表面焊一层（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）复合涂层,研究了不同钎焊工艺对涂层自身结合强度、涂层与基体间连接强度以及涂层抗磨料磨损性能的影响。钎焊工艺为１０８０℃×１０ｍｉｎ时,涂层自身结合强度为１４６ＭＰａ;涂层与基体间的最高连接强度为３６７ＭＰａ。涂层的抗磨料磨损性能比Ｃｏ－Ｃｒ－Ｗ堆焊涂层和（ＷＣ－Ｃｏ／ＮｉｒＢＳｉ）火焰堆焊层的高。     

结构化仿生表面的制备及其应用

结构化仿生表面作为复合材料领域重要的、前瞻性的课题,是近30年发展起来的新型多学科交叉领域,其在工业、生物工程、现代医学、军事、能源等领域以及日常生活方面都有着广泛的应用。讨论了结构化仿生表面在减粘降阻和超疏水领域的应用,综述了近年来国内外结构化仿生表面的一些主要制备方法及其优缺点,并对今后的发展进行了展望。     

Fe-Ni-Cr合金表面等离子喷涂氧化铝陶瓷涂层的阻氢性能

采用等离子喷涂、气相热充氢等技术研究了在Fe－Ni－Cr合金表面喷涂氧化铝陶瓷涂层对其阻氢性能的影响．结果表明，氧化铝陶瓷涂层使Fe－Ni－Cr合金的阻氢性能明显提高，且白氧化铝陶瓷涂层较灰氧化铝涂层的阻氢效果好．     

(WC-Co/NiCrBSi)钎焊涂层结合机制及磨损性能研究

采用真空钎焊工艺,将ＷＣ－Ｃｏ硬质合金粉和ＮｉＣｒＢＳｉ（ＡＷＳＢＮｉ－２）合金粉钎焊到４５＃钢表面,得到（ＷＣ－Ｃｏ／ＮｉＣｒＢＳｉ）钎焊涂层。不同钎焊工艺下,涂层及涂层／基体的拉伸强度分别达１００—１４０ＭＰａ和３００－３６０ＭＰａ。初步分析了钎焊涂层结合机制。涂层的磨料磨损性能远高于同配比的火焰堆焊涂层及Ｃｏ－Ｃｒ－Ｗ堆焊层     

化学沉积法制备Ni—Cu—P／CNTs复合涂层及其表征

利用化学沉积法在45^#钢基体上成功制备出Ni—Cu-P／CNTs复合涂层，为了降低碳纳米管的长径比以及提高在镀液中的分散性，对其硝酸纯化、15min球磨处理，研究了沉积液组成对Ni-Cu-P／CNTs复合涂层沉积速率的影响，通过TEM、SEM和EDS表征了复合涂层的表面形貌和微观结构。结果表明：碳纳米管的分散性良好，在复合涂层中分布均匀，复合涂层在400℃热处理后结构更加致密，EDS表明复合涂层中碳纳米管的质量分数达到3．68％。     

Fe—Ni—Cr合金等表面等离子喷涂氧化铝陶瓷涂层的阻氢性能

采用等离子喷涂，气相热充氢等技术研究了在Ｆｅ－Ｎｉ－Ｃｒ合金表面喷涂氧化铝陶瓷涂层对其阻氢性能的影响。结果表明，氧化铝陶瓷涂层使Ｆｅ－Ｎｉ－Ｃｒ合金的阻氢性能明显提高，且白氧化铝陶瓷涂层较灰氧化铝涂层的阻氢效果好。     

等离子喷涂制备HA/ZrO2复合涂层

采用等离子喷涂技术,在Ｔｉ－６Ａｌ－４Ｖ基体上成功地制备了羟基磷灰石／氧化锆（ＨＡ／ＺｒＯ_２）复合涂层,对涂层的微观结构、相组成和结合强度进行了研究,并以模拟体液试验评估涂层的生物活性．结果表明,复合涂层具有较为均匀的微观结构．ＨＡ／ＺｒＯ_２复合涂层的结合强度明显高于 ＨＡ涂层, ＨＡ／６０ ｗｔ％ ＺｒＯ_２涂层的结合强度高达 ２８．５ＭＰａ,为 ＨＡ涂层的 ２．２倍．复合涂层在模拟体液中浸泡一段时间后,表面覆盖一层碳酸磷灰石（ｃａｒｂｏｎａｔｅ－ａｐａｔｉｔｅ）,表明涂层具有良好的生物活性．     

两步电沉积法制备HA-Ti/HA复合涂层的研究

为了提高金属基羟基磷灰石（HA）涂层的结合强度,采用复合电沉积一电沉积两步法在含Ti粉的钙磷电解液中制备HA—Ti／HA复合涂层,对涂层的组分结构、表面形貌、热稳定性、结合强度和生物活性进行了研究．实验结果表明：两步法制备的底层为HA—Ti复合涂层,外层为纯HA涂层的HA—Ti／HA复合涂层既提高了涂层的结合强度,又保证了涂层的生物活性．当涂层中Ti粉的质量分数为51．2wt％时,涂层与基体的结合强度达到21．2MPa,约为纯HA涂层的3倍．模拟体液浸泡7天后,涂层表面即被一层球状碳磷灰石覆盖,具有良好的生物活性,与纯HA涂层相比,复合涂层具有更好的耐蚀性能．     

Coating of metal implant materials with strontium

The aim of this study was to show that cathodic polarization can be used for coating commercial implant surfaces with an immobilized but functional and bioavailable surface layer of strontium (Sr). Moreover, this study assessed the effect of fluorine on Sr-attachment. X-ray photoelectron spectroscopy revealed that addition of fluorine (F) to the buffer during coating increased surface Sr-amounts but also changed the chemical surface composition by adding SrF₂ alongside of SrO whereas pre-treatment of the surface by pickling in hydrofluoric acid appeared to hinder Sr-attachment. Assessment of the bio-availability hinted at a positive effect of Sr on cell differentiation given that the surface reactivity of the original surface remained unchanged. Additional SrF₂ on the surface appeared to reduce undesired surface contamination while maintaining the surface micro-topography and micro-morphology. Anyhow, this surface modification revealed to create nano-nodules on the surface.     

Condition assessment of concrete in hydraulic structures by surface wave non-destructive testing

Maintenance and rehabilitation of concrete structures affected by alkali-aggregate reaction (AAR) require conducting detailed assessment of the concrete conditions, mainly close to the surface where the damage is more severe. This paper presents in situ investigations by surface wave testing of near-surface AAR damage in two hydraulic structures. The survey was carried out using a non-intrusive multi-sensor method that involves frequency–wavenumber analysis of surface waves. The method allows solving Rayleigh surface wave propagation modes required for the determination of the shear wave velocity in terms of depth. The variation of Young’s modulus with concrete depth can be estimated from the obtained shear wave velocity profile. Two different cases of surface wave propagation, typical of concrete structures, are discussed in this paper. The tests were conducted from the concrete surface only and the subsurface quality was mapped up to a depth of 1.50 m. The applications show that the proposed surface wave method is a potential non-destructive evaluation method that can be used to detect and locate near surface damage in concrete structures.

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Kinetic Monte Carlo simulation of Cu thin film growth

A three-dimensional kinetic Monte Carlo technique has been developed for simulating the growth of thin Cu films. The model involves incident atom attachment, surface diffusion of the atoms on the growing surface and atom detachment from the growing surface. A significant improvement in calculation of activation barriers for the surface atom diffusion on the growing film was made. The related effects caused by surface atom diffusion were taken into account. The results showed that there exist a transition temperature T_t at a certain deposition rate. When the substrate temperature approaches T_t, the growing surface becomes smoother and the relative density of the films increases. The surface roughness minimizes and the relative density saturates at T_t. The surface roughness increases with increased substrate temperature when the temperature is higher than T_t. T_t is a function of the deposition rate. The influence of the deposition rate on the surface roughness is dependent on the substrate temperature. The simulation results also showed that the relative density decreases with increasing deposition rate and average thickness of the film.     

Superhydrophobic optically transparent silica films formed with a eutectic liquid

A eutectic liquid (choline chloride and urea) that served as a templating agent in sol-gel processing was used to prepare thin silica films on glass microscope slides. Subsequent extraction of the eutectic liquid yielded a film with a rough surface. After treating the film surface with a fluoroalkyl silane, the surface became superhydrophobic with a contact angle ∼ 170° and a contact angle hysteresis < 10°. The optical transmittance of the film coated on the glass slide was comparable to that of the microscope glass slide. Atomic Force Microscopy (AFM) was used to characterize the surface structures; a tipless probe allowed measurement of the force of interaction with superhydrophobic surfaces. The interaction force between the AFM probe and the superhydrophobic surface was reduced greatly compared to that between the probe and the flat surface treated with fluoroalkyl silane.     

Dynamic fracture behaviour of Fe78Si9B13 metallic glass ribbon under laser shock loading

The fracture behaviour of Fe₇₈Si₉B₁₃ metallic glass under laser shock loading was investigated. Morphologies of the fracture surface and laser irradiated surface were characterized using scanning electron microscope. The results show that the fracture surface consists of sliding region and final fracture region with crack propagation. Liquid droplets and melted belts are scattered on the fracture surface as the notable features compared with fracture surface morphology under quasistatic loading, indicating the significant temperature increase in shear bands during dynamic loading. The primary and secondary shear bands are distributed on the specimen surface resulting from the simultaneous operation of multiple shear bands at high strain rates. Ripples with the characteristic spacing of about 1 µm are generated on the laser irradiated surface because of the interaction of laser pulse with solid surface.     

Structural dependence of ionic motion at interfaces between NaCl crystal surfaces and supersaturated solutions in crystallization process

The effects of surface structure and solution concentration on crystal morphology have been investigated through molecular dynamics (MD) simulation in the NaCl crystallization process. Four types of crystal surface structures were prepared for simulation. The probability of ion existence suggests that the solute ions were hardly taken into flat surfaces, while they were easily taken into roughs with some kinks and steps. This is because solute ions are more stable at a kink than at a terrace. The present simulated results suggest that the mechanism of crystal growth is dependent on the solution concentration. It was demonstrated that some ions are slotted on the crystal surface at low supersaturation after moving to the crystal surface. Under high supersaturation, the clusters are formed and adsorbed on the crystal surface. When comparing the crystal growth rates of Na⁺ and Cl⁻, the attractive force of Na⁺ from the crystal surface was found to be larger than that of Cl⁻. Moreover, the repulsive force of Na⁺ from the crystal surface was smaller than that of Cl⁻ in approaching the crystal surface. The adsorption of Na+ was also found to occur before that of Cl⁻.     

Effects of LDPE film on the properties of copper/LDPE composites for intrauterine contraceptive device

Copper/low density polyethylene (LDPE) composites covered with LDPE film on the surface were prepared for intrauterine contraceptive device (IUD). Cu²⁺ release rates of the composites were determined by absorbance measurements. The surface characteristics of the composites after incubated for 5 months were investigated by SEM and EDX techniques. The results show that the existence of LDPE film on the surface of the composites decreases the release rate of Cu²⁺, especially the burst release of Cu²⁺ at initial period. The undesirable deposits, which are observed on the surface of the composite without LDPE film, are not detected on the surface of the composite with LDPE film, indicating that the presence of LDPE film can effectively prevent the formation of deposits on the composite surface. Results obtained from this study suggest that the existence of LDPE film on the composite surface may alleviate the side effects (bleeding, abdominal pain and inflammatory complication) of IUD resulting from the burst release and the deposit formation.     

Aminosilane densities on nanotextured silicon

Aminosilanization of hydroxylated surfaces is used for attachment of biomolecules which have various applications. The density of the surface amine group is of importance as it determines the density of the subsequent immobilized or self-assembled molecules over the aminosilylated layer; hence there is a need to understand the processes and the phenomena that control the surface aminosilane density. Crystalline silicon surfaces, nanotextured using the HF/HNO₃/H₂O chemistry, were silanized using aminosilanes (APTES and APTMS). Masks were not used to obtain the surface topography; rather the surface textures (< 100 nm RMS roughness) were controlled by process conditions such as temperature, etchant composition and etch time. The aminosilane densities were dependent on the surface texture and composition. Our results showed that oxidation of the surface resulted in lower silane densities. While increased surface area enhanced the densities, processes like the HNO₃-rich chemistries while increasing the surface area were also associated with surface oxidation resulting in lower densities compared to surfaces textured with HF-rich compositions.     

Proving the existence of nanobubbles produced by hydrodynamic cavitation and their significant effects in powder flotation

Selective attachment of nanobubles (NBs) generated in different conditions on the surface of valuable minerals during flotation separation was a challenge that needs to be addressed. This investigation filled this gap and proved the existence of NBs on the target mineral's surface and their selective effectiveness through the process. The bubble size analysis results showed that the mean diameter of bubbles was between 60 and 70 nm; thus, they could be correctly called “nanobubbles”. Flotation test results showed a significant increase in the flotation recovery (by 37%) and grade (more than 1%) of fine phosphate ore sample (d₈₀: 37 µm) using NBs that generated in the presence of collector. Interestingly, surface analyses of flotation products showed that the amounts of flotation collector adsorbed onto the surface of floated particles was decreased in the presence of NBs compared with their absence. The change in the particle surface (zeta) potential in the presence of NBs also provides additional evidence of NBs “adsorbed” (i.e., the surface NBs) onto the particle surface. These results indicated that NBs produced by hydrodynamic cavitation could adsorb onto the target mineral particles. This adsorption could change their surface properties, improve their hydrophobicity and surface potentials, and enhanced the bubble-particle attachment in flotation.     

Ar ion milling-induced suppression of surface oxidation in Fe70Co30 thin films

We show from the depth-resolved X-ray absorption analysis that the degree of surface oxidation of Fe₇₀Co₃₀ thin films is reduced by Ar⁺ ion milling even if the film is exposed to air after ion milling. The milled film has thinner surface oxide layer and smaller ratio of Fe oxide component in the surface layer than those of the as-deposited film. It is also indicated that selective oxidation of Fe proceeds accompanied by the movement of Fe atoms toward the surface. The suppression of oxidation is explained by the obstruction of Fe movement toward the surface by the milling-induced disorder.