Nano-diamond/Ni复合电刷镀层的组织形貌的研究

以45#钢为基体,制备了普通镍镀层和nano-diamond/Ni复合刷镀层,采用扫描电镜、能谱仪、X射线衍射仪和金相显微镜等设备对比研究了两种镀层的组织形貌。金相显微镜和扫描电镜分析结果表明,与普通镍镀层相比,nano-diamond/Ni复合刷镀层的表面更加平整、致密,组织更加细化;nano-dia-mond/Ni复合刷镀层表面呈典型的"菜花头"形状,弥散分布的纳米金刚石被镍包裹。能谱仪分析结果表明,nano-diamond/Ni复合刷镀层中纳米颗粒特征元素C的质量分数为7.37%。X射线衍射分析结果表明,随着纳米金刚石加入量的增加,镀层表面晶粒尺寸逐渐减小。

Influence of nano-diamond content on the microstructure,mechanical and thermal properties of the ZK60 composites

The effect of nano diamond(ND)content on the microstructure,mechanical properties,and thermal conductivity of ZK60+x(x=0,0.05,0.1,0.15,0.2 wt.%)ND composites were investigated.The microstructures of ND/ZK60 composites were observed,which indicated that the nanoscale MgZn_(2) and ND particles distributed evenly in theα-Mg matrix.The tensile yield strength(TYS)and compressive yield strength(CYS)of the composites first increased remarkably and then decreased with further increasing the ND content.Due to the surface area of the matrix-diamond interface increased and the grains sizes of composites decreased with the amount of ND increase,which cause the coefficient of thermal expansion(CTE)of the composites reduced significantly.Meanwhile,the thermal conductivity of the composite material decreases from 129 W·m^(−1)·K^(−1) to 116 W·m^(−1)·K^(−1) with the content of ND increasing from 0.05%to 2.0%.The thermal conductivity of the composites increases to the maximum and then decrease with the increase of temperature(in temperature range of 273-573 K).The ZK60+0.05 ND showed superior mechanical and thermal conductivity property,TYS of 343.97 MPa,CYS of 341.74 MPa,elongation of 15.71%,CTE of 7.3×10^(−6)K^(−1),and thermal conductivity of 129 W·m^(−1)·K^(−1) at room temperature.It is demonstrated that the ND content has an obvious influence on the microstructure,mechanical properties,and thermal conductivity of ND/ZK60 composites.

High temperature tribological behaviors of nano-diamond as oil additive

The tribological behaviors of the nano-diamond particles including the nano- diamond and the nano-diamond modified were studied at high temperature using SRV multifunctional test system. The worn steel surfaces were analyzed by means of X-ray photoelectron spectroscopy (XPS). The results show that nano-diamond particles can obviously improve the antiwear and friction reducing properties of the base oil at high temperature and the high load. The friction coefficient of the nano-diamond is very low at 200 ℃ when the test load is not more than 20 N. This tribological behaviors should attributed to the similarly to “ball bearing” lubrication action of the nano-diamond particles, so the movement between tribological pairs become sliding/rolling. The nano-diamond modified by dimer ester possesses excellent antiwear and friction reducing performance at 500 ℃ and load 500 N. The tribochemical reaction film between the nano-diamond particles and the renascent wear surface plays dominating lubrication role and the presence of the dimer ester on the rubbing surface can be propitious to form lubrication film containing nano- diamond on the worn surface at high temperature and high load.

Effect of Gas Sources on the Deposition of Nano-Crystalline Diamond Films Prepared by Microwave Plasma Enhanced Chemical Vapor Deposition

Nano-crystalline diamond （NCD） films were deposited on silicon substrates by a microwave plasma enhanced chemical vapor deposition （MPCVD） reactor in C2H5OH/H2 and CH4/H2/O2 systems, respectively, with a constant ratio of carbon/hydrogen/oxygen. By means of atomic force microscopy （AFM） and X-ray diffraction （XRD）, it was shown that the NCD films deposited in the C2H5OH/H2 system possesses more uniform surface than that deposited in the CH4/H2/O2 system. Results from micro-Raman spectroscopy revealed that the quality of the NCD films was different even though the plasmas in the two systems contain exactly the same proportion of elements. In order to explain this phenomenon, the bond energy of forming OH groups, energy distraction in plasma and the deposition process of NCD films were studied. The experimental results and discussion indicate that for a same ratio of carbon/hydrogen/oxygen, the C2H5OH/H2 plasma was beneficial to deposit high quality NCD films with smaller average grain size and lower surface roughness.

Research on a Diamond Tip Wear Mechanism in Atomic Force Microscope-based Micro/nano-machining

The object is to investigate the wear of an atomic force microscope (AFM) diamond tip when conducting micro/nano machining on single crystal silicon surface. The experimental research and theoretical analysis were carried out on the worn tip in terms of wear rate, wear mechanism and the effect of the tip wear on micro machining process. The wear rate was calculated as 1.7(10～10mm 3/(N·m) by using a theoretical model combined with the experimental results. Through an integration of an AFM observation on the worn tip features with the FEM simulation of the stress distribution, in addition to the unit cutting force calculation on the AFM diamond tip, the wear mechanism of the AFM diamond tip was concluded as mainly chemical wear, and the wear process was also elaborated as well.

Preparation and characterization of nano-crystalline diamond films on glass substrate

Adherent nano diamond films were successfully deposited on glass substrate bymicrowave plasma assisted CVD method in H_2-CH_4 and Ar-CH_4 environment. Raman, AFM (Atomic ForceMicroscope), TEM (Transmission Electron Microscope), FTIR, and Nano Indentation techniques were usedfor characterization of the obtained nano diamond films. It was found that the average grain sizewas less than 100 nm with a surface roughness value as low as 2 nm. The nano diamond films werefound to have excellent transparency in visible and IR spectrum range, and were as hard as naturaldiamond. Experimental results were presented. Mechanisms for nano diamond film deposition werediscussed.

Preparation of Nano-Crystalline Diamond Films on Poly-Crystalline Diamond Thick Films by Microwave Plasma Enhanced Chemical Vapor Deposition

Nano-crystalline diamond （NCD） films were prepared on poly-crystalline diamond （PCD） thick flims by the microwave plasma enhanced chemical vapor deposition （MPCVD） method. Free standing PCD thick film （50 mm in diameter） with a thickness of 413 μm was deposited in CHn/H2 plasma. It was then abraded for 2 hours and finally cut into pieces in a size of 10×10 mm^2 by pulse laser. NCD fihns were deposited on the thick film substrates by introducing a micro-crystalline diamond （MCD） interlayer. Results showed that a higher carbon concentration （5%） and a lower substrate temperature （650℃） were feasible to obtain a highly smooth interlayer, and the appropriate addition of oxygen （2%） into the gas mixture was conducive to obtaining a smooth nano-crystalline diamond film with a tiny grain size.

Ellipsometric analysis and optical absorption characterization of nano-crystalline diamond film

A nano-crystalline diamond (NCD) film with a smooth surface was successfully deposited on silicon by a hot filament chemical vapor deposition (HFCVD) method. Scanning electron microscopy (SEM), atomic force microscopy (AFM), RAMAN scattering spectra, as well as spectroscopic ellipsometry were employed to characterize the as-grown film. By fitting the spectroscopic ellipsometric data in the energy range of 0.75?1.50 eV with a three-layer model, Si|diamond+non-diamond|diamond+ non-diamond+void|air, the optical constants are obtained. The refractive index of the NCD film varies little from 2.361 to 2.366 and the extinction coefficient is of the order of 10?2. According to the optical transmittance and absorption coefficient in the wavelength range from 200 to 1 100 nm, the optical gap of the film is estimated to be 4.3 eV by a direct optical transition mechanics.

Preparation Nano-Diamond Film by Sol-Gelled Coating Method for Field Emission Display

The mixture of Nano-graphite and organic vehicles doped to Nano-diamond paste. The suitable paste proportion was found. Nano-diamond film (NDF) was prepared by sol-gel coating method on ITO glass at 3000/min. The field emission characteristics of luminance-current, luminance-voltage and luminance-power of Nano-diamond film were analyzed and tested. Comparing these tested curves, the luminance was well proportional to current was got. Theoretic, the inner resistance of NDF field emission display (FED) consumes electric energy and real voltage change between the cathode and the anode of NDF-FED was very small after electrons emit. So the characteristic of NDF-FED was preferable to describe by luminance-current linear relationship, which was advantageous to device tested and designed.

Application of rare-earth and nano elements on diamond cup wheels

Diamond cup wheel is used widely as an important tool for machining ceramic tile.In this paper,nano rare-earth oxide and nano carbide were added in the segments of seven kinds of diamond cup wheels.The performance of diamond cup wheels were tested on a special designed test machine by grinding two kinds of ceramic tiles.The surface morphology of the segments was examined by Scanning Election Microscopy(SEM) and the micro-hardness of segments was measured.The results showed that nano rare-earth oxide and nano carbide can fine segment micro structure,make grain boundary clear and increase grasping of diamond grits.They can increase also the wear resistance of diamond cup wheels as well as the grinding ratio.

Sin-QuEChERS Nano净化柱结合气相色谱-串联质谱法快速筛查石斛中84种农药残留

利用Sin-QuEChERS Nano净化柱结合气相色谱-串联质谱(GC-MS/MS)分析,建立了石斛基质中84种不同极性农药残留的快速筛查方法。比较了采用不同的提取溶剂(1%乙酸乙腈、丙酮)和不同的提取方式(加水浸泡和不加水浸泡)下目标物的提取效率。利用金钗石斛样品系统比较了Sin-QuEChERS Nano法与经典的基质固相分散法(dSPE)、固相萃取法(SPE)、QuEChERS法的净化效果及提取回收率,以及净化效果较好的Sin-QuEChERS Nano法与dSPE法基质效应的差异。目标物经DB-1701MS石英毛细管色谱柱(30 m×0.25 mm×0.25μm)程序升温分离,GC-MS/MS多反应监测(MRM)模式检测,基质匹配溶液外标法定量。通过GC-MS/MS检测方法对金钗石斛和铁皮石斛中的84种代表性农药进行了方法学验证。结果表明:各目标物在不同范围内呈良好的线性相关,相关系数(r^(2))均>0.990,方法的检出限(LOD,S/N=3)为1.5~5.8μg/kg,方法的定量限(LOQ,S/N=10)为5.0~15.0μg/kg。在两个水平下,目标农药的加标回收率为68.7%~116.2%,相对标准偏差(RSD,n=6)均低于15%。与其他经典的前处理方法相比,Sin-QuEChERS Nano法在净化效果方面表现更好,该法不仅可以有效去除色素、有机酸、碱性干扰物等物质,还可以节省样品制备时间,避免溶剂转移造成的损失,无需进一步涡旋或离心,是一种简单而有效的提取物纯化程序。该方法灵敏、快速、简便、可靠,有效地提高了石斛中农药快速筛查时的检测效率,具有较强的实际应用价值。此外,所开发的方法可以进一步扩展目标农药的类型,并可以用于检测其他更多食品及中药材中的农药残留。

Simple-QuEChERS Nano结合GC-MS/MS同时检测全血中的97种农药

建立了Simple-QuEChERS Nano结合气相色谱-串联质谱(GC-MS/MS)同时检测血液中97种农药的方法,并对基质条件、提取溶剂以及净化材料进行了优化。0.5 mL血液样品经3倍水稀释混匀,使用2.0 mL乙酸乙酯提取后振荡、离心,过Simple-QuEChERS Nano净化柱及0.22μm有机微孔滤膜后,采用多反应监测模式(MRM)进行分析。结果显示,97种农药在一定质量浓度范围内线性关系良好(r2≥0.9873),除丙烯菊酯(检出限和定量下限分别为11.03、36.76 ng/mL)外,其余农药的检出限为0.06~4.27 ng/mL,定量下限为0.18~14.24 ng/mL。采用空白全血进行加标回收实验,97种农药在100、200、400 ng/mL 3个加标水平下的回收率为32.2%~120%,日内精密度为1.9%~11%,日间精密度为3.6%~13%。该方法由传统QuEChERS方法改进,绿色环保、操作简单、快速高效,可用于血液中多种农药的同时检测,用于实际案件血液样品中农药的筛查与定性定量检验,获得了良好的结果。

NANO碳净化-超高效液相色谱-串联质谱法测定东北黑土壤中多农残含量

本文使用NANO碳净化柱对土壤中的31种农药进行净化,并且通过超高效液相色谱-串联质谱法(UPLC-MS/MS)进行测定。土壤样品经过NANO碳净化柱,净化效果良好。31种农药的检出限为0.001~0.01mg/kg,定量限为0.003~0.033mg/kg,添加回收率在70%~120%之间,相对标准偏差(RSD)在0%~10%之间。结果表明,该方法简单、快捷、灵敏度高,线性范围、回收率和精密度均适合土壤中的31种农药残留检测,在土壤农药残留筛查中具有较好的应用前景。

Micro/nano Indentation and Single Grit Diamond Grinding Mechanism on Ultra Pure Fused Silica

The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.

Deformation Analysis of Micro/Nano Indentation and Diamond Grinding on Optical Glasses

The previous research of precision grinding optical glasses with electrolytic in process dressing （ELID） technology mainly concentrated on the action of ELID and machining parameters when grinding, which aim at generating very ＂smoothed＂ surfaces and reducing the subsurface damage. However, when grinding spectrosil 2000 and BK7 glass assisted with ELID technology, a deeply comparative study on material removal mechanism and the wheel wear behaviors have not been given yet. In this paper, the micro/nano indentation technique is initially applied for investigating the mechanical properties of optical glasses, whose results are then refereed to evaluate the machinability. In single grit diamond scratching on glasses, the scratching traces display four kinds of scratch characteristics according to different material removal modes. In normal grinding experiments, the result shows BK7 glass has a better machinability than that of spectrosil 2000, corresponding to what the micro/nano indentation vent revealed. Under the same grinding depth parameters, the smaller amplitude of acoustic emission （AE） raw signals, grinding force and grinding force ratio correspond to a better surface quality. While for these two kinds of glasses, with the increasing of grinding depth, the variation trends of the surface roughness, the force ratio, and the AE raw signals are contrary, which should be attributed to different material removal modes. Moreover, the SEM micrographs of used wheels surface indicate that diamond grains on the wheel surface after grinding BK7 glass are worn more severely than that of spectrosil 2000. The proposed research analyzes what happened in the grinding process with different material removal patterns, which can provide a basis for producing high-quality optical glasses and comprehensively evaluate the surface and subsurface integrity of optical glasses.

MICRO/NANO-MACHINING ON SILICON SURFACE WITH A MODIFIED ATOMIC FORCE MICROSCOPE

To understand the deformation and removal mechanism of material on nano-scale at ultralow loads,a systemic study on AFM micro/nano-machining on single crystal ailicon is conducted. The results indicate that AFM nano- machining has a precisely dimensional controllability and a good surface quality on nanometer scale.A SEM is adopted to observe nano-machined region and chips,the results indicate that the material removal mechanisms change with the applied normal load. An XPS is used to analyze the changes of chemical composition inside and outside the nano-machined region respectively.The nano-indentation which is conducted with the same AFM diamond tip on the machined region shows a big discrepancy compared with that on the macro-scale. The calculated results show higher nano-hardness and elastic modulus than normal values .This phenomenon on be regarded as the indentation size effect(ISE).

Characterization of the Diamond-like Carbon Based Functionally Gradient Film

Diamond-like carbon coatings have been used as solid lubricating coatings in vacuum technology for their good physical and chemical properties. In this paper, the hybrid technique of unbalanced magnetron sputtering and plasma immersion ion implantation (Plll) was adopted to fabricate diamond-like carbon-based functionally gradient film, N/TiN/Ti(N,C)/DLC, on the 304 stainless steel substrate. The film was characterized by using Raman spectroscopy and glancing X-ray diffraction (GXRD), and the topography and surface roughness of the film was observed using AFM. The mechanical properties of the film were evaluated by nano-indentation. The results showed that the surface roughness of the film was approximately 0.732 nm. The hardness and elastic modulus, fracture toughness and interfacial fracture toughness of N/TiN/Ti(N,C)/DLC functionally gradient film were about 19.84 GPa, 190.03 GPa, 3.75 MRa.m1/2 and 5.68 MPa.m1/2, respectively. Compared with that of DLC monolayer and C/TiC/DLC multilayer, this DLC gradient film has better qualities as a solid lubricating coating.

Effect of Nano - Titanium Dioxide with Different Antibiotics against Methicillin-Resistant Staphylococcus Aureus

The different investigation has been carried out on the biological activities of titanium dioxide nanoparticle but the effect of this nano product on the antibacterial activity of different antibiotics has not been yet demonstrated. In this study the nano size TiO2 is synthesized using citric acid and alpha dextrose and the enhancement effect of TiO2 nanoparticle on the antibacterial activity of different antibiotics was evaluated against Methicillin-resistant Staphylococcus aureus (MRSA). During the present study, different concentrations of nano-scale TiO2 were tested to find out the best concentration that can have the most effective antibacterial property against the MRSA culture. Disk diffusion method was used to determine the antibacterial activity of these antibiotics in the absence and presence of sub inhibitory concentration of TiO2 nano particle. A clinical isolate of MRSA, isolated from Intensive Care Unit (ICU) was used as test strain. In the presence of sub-inhibitory concentration of TiO2 nanoparticle (20 μg/disc) the antibacterial activities of all antibiotics have been increased against test strain with minimum 2 mm to maximum 10mm. The highest increase in inhibitory zone for MRSA was observed against pencillin G and amikacin (each 10 mm). Conversely, in case of nalidixic acid, TiO2 nanoparticle showed a Synergic effect on the antibacterial activity of this antibiotic against test strain. These results signify that the TiO2 nanoparticle potentate the antimicrobial action of beta lactums, cephalosporins, aminoglycosides, glycopeptides, macrolids and lincosamides, tetracycline a possible utilization of nano compound in combination effect against MRSA.

Structure and Performance of Ce-nano PO_4^(3-)/ZrO_2 Solid Acid Catalyst for Producing Biodiesel

The biodiesel prepared from Xanthoceras Sorbiflia Bunge Oil catalyzed by Ce doped nano PO_4^(3-)/ZrO_2 was investigated. A maximum biodiesel yield of 91.83% was achieved at the concentration of Ce^(3+) up to 0.1 mol/L, calcination temperature 500 °C, calcination time 3.0 h, and the concentration of phosphoric acid of 3.5 mol/L. Ce-nano PO_4^(3-)/ZrO_2 catalyst activities were correlated with the observed physico-chemical characteristics derived from scanning electron microscopy(SEM), FT-infrared(FT-IR), X-ray diffraction(XRD), thermogravimetric(TG) and Brunauer-Emmett-Teller(BET) analysis. The delayed crystallization of ZrO_2 made surface oxides have more defects which were beneficial to the adsorption of PO_4^(3-) by the concentration increment of Ce^(3+). The chemical composition of synthesized biodiesel was confirmed by gas chromatography(GC). The characteristics of Xanthoceras Sorbiflia Bunge oil were found within the optimal range in accordance with Chinese No. 0 diesel standard as a substitute diesel fuel.

Microstructure and properties of the sintered diamond reinforced by diamond-MWCNTs composite fibers

A new type of sintered diamond reinforced by diamond MWCNTs composite fibers which were randomly orientated and even distributed in the diamond matrix was synthesized by using 3wt%mullti-walled carbon nanotubes（MWCNTs） as starting additive under high pressure of 5.8 GPa at temperature of 1500℃for 1 min.A special polycrystalline diamond structure of direct bonding of both diamond to diamond and diamond to diamond-MWCNTs composite fiber was observed.The testing results show that it possesses not only high hardness（49～52 GPa） and Young’s modulus（878 GPa） but also high bending strength（1320～1540 GPa） and fracture toughness(9.0～9.2 MPa·m1/2) as it was theoretically predicted.The high performances of the composite were contributed by the fiber strengthening effect and the special structure which can offer more extensive diamond to diamond bonding.