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1.
Sansoz F  Gang T 《Ultramicroscopy》2010,111(1):11-19
We present a new method to improve the accuracy of force application and hardness measurements in hard surfaces by using low-force (<50 μN) nanoindentation technique with a cube-corner diamond tip mounted on an atomic force microscopy (AFM) sapphire cantilever. A force calibration procedure based on the force-matching method, which explicitly includes the tip geometry and the tip-substrate deformation during calibration, is proposed. A computer algorithm to automate this calibration procedure is also made available. The proposed methodology is verified experimentally by conducting AFM nanoindentations on fused quartz, Si(1 0 0) and a 100-nm-thick film of gold deposited on Si(1 0 0). Comparison of experimental results with finite element simulations and literature data yields excellent agreement. In particular, hardness measurements using AFM nanoindentation in fused quartz show a systematic error less than 2% when applying the force-matching method, as opposed to 37% with the standard protocol. Furthermore, the residual impressions left in the different substrates are examined in detail using non-contact AFM imaging with the same diamond probe. The uncertainty of method to measure the projected area of contact at maximum force due to elastic recovery effects is also discussed.  相似文献   

2.
《Ultramicroscopy》2011,111(1):11-19
We present a new method to improve the accuracy of force application and hardness measurements in hard surfaces by using low-force (<50 μN) nanoindentation technique with a cube-corner diamond tip mounted on an atomic force microscopy (AFM) sapphire cantilever. A force calibration procedure based on the force-matching method, which explicitly includes the tip geometry and the tip-substrate deformation during calibration, is proposed. A computer algorithm to automate this calibration procedure is also made available. The proposed methodology is verified experimentally by conducting AFM nanoindentations on fused quartz, Si(1 0 0) and a 100-nm-thick film of gold deposited on Si(1 0 0). Comparison of experimental results with finite element simulations and literature data yields excellent agreement. In particular, hardness measurements using AFM nanoindentation in fused quartz show a systematic error less than 2% when applying the force-matching method, as opposed to 37% with the standard protocol. Furthermore, the residual impressions left in the different substrates are examined in detail using non-contact AFM imaging with the same diamond probe. The uncertainty of method to measure the projected area of contact at maximum force due to elastic recovery effects is also discussed.  相似文献   

3.
Nanoindentation technology is developing toward the in situ test which requires miniaturization of indentation instruments. This paper presents a miniaturization nanoindentation device based on the modular idea. It mainly consists of macro-adjusting mechanism, x-y precise positioning platform, z axis precise driving unit, and the load-depth measuring unit. The device can be assembled with different forms and has minimum dimensions of 200 mm × 135 mm × 200 mm. The load resolution is about 0.1 mN and the displacement resolution is about 10 nm. A new calibration method named the reference-mapping method is proposed to calibrate the developed device. Output performance tests and indentation experiments indicate the feasibility of the developed device and calibration method. This paper gives an example that combining piezoelectric actuators with flexure hinge to realize nanoindentation tests. Integrating a smaller displacement sensor, a more compact nanoindentation device can be designed in the future.  相似文献   

4.
Cupric oxide (CuO) semiconducting thin films were prepared at various copper sulfate concentrations by dip coating. The copper sulfate concentration was varied to yield films of thicknesses in the range of 445–685 nm by surface profilometer. X‐ray diffraction patterns revealed that the deposited films were polycrystalline in nature with monoclinic structure of (?111) plane. The surface morphology and topography of monoclinic‐phase CuO thin films were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Surface roughness profile was plotted using WSxM software and the estimated surface roughness was about ~19.4 nm at 30 mM molar concentration. The nanosheets shaped grains were observed by SEM and AFM studies. The stoichiometric compound formation was observed at 30 mM copper sulfate concentration prepared film by EDX. The indirect band gap energy of CuO films was increased from 1.08 to 1.20 eV with the increase of copper sulfate concentrations. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

5.
The present study offers for the first time a correlation between static nanomechanical properties (nanohardness (H), elastic modulus (E), H/E and H 3/E 2 ratio) and dynamic properties (resulting from nanoscratch measurements) for Metal–ZrN thin films (Inconel–ZrN, Cr–ZrN and Nb–ZrN) as well as monolayer polycrystalline ZrN thin films. Metal–ZrN thin films have a great industrial potential, as they can combine high hardness with good elasticity and toughness making them effective for wear resistant application. Nanomechanical and nanotribological properties of Metal–ZrN and ZrN thin films deposited by DC unbalanced magnetron sputtering were investigated using an atomic force microscope interfaced with a Hysitron Triboscope. The elastic recovery of thin films under a normal load applied during nanoindentation was evaluated and correlated with elastic recovery of thin films under dynamic loading during nanoscratch measurements in order to asses which film compositions provide superior wear resistance. It is demonstrated that dynamic elastic recovery measurements correlated well with those derived from static nanoindentation tests. The nanoscratch test combines both normal and tangential loading, therefore, it is expected to be an even better predictor of wear-resistance. The AFM nanoindentation and nanoscratch measurements show superior nanomechanical and nanotribological properties for Metal–ZrN thin films when compared to polycrystalline ZrN thin films.  相似文献   

6.
单晶蓝宝石的延性研磨加工   总被引:1,自引:1,他引:0  
为实现单晶蓝宝石的延性研磨加工,采用纳米压痕和划痕法测试并分析了单晶蓝宝石(0001)面的微纳力学特性,建立了单颗圆锥状磨粒的压入模型并计算了延性研磨加工的受力临界条件,分析了金刚石磨粒嵌入合成锡研磨盘表面的效果.对单晶蓝宝石进行了延性研磨加工试验,采用NT9800白光干涉仪、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等方法分析了单晶蓝宝石的延性研磨表面特征.试验结果表明:采用纳米压痕和划痕法可以为单晶蓝宝石的延性研磨加工提供工艺参数,单晶蓝宝石的延性堆积的极限深度为100 nm,金刚石磨粒的嵌入及在适当载荷下可以实现蓝宝石的延性研磨加工,实验条件下的最佳载荷为21 kPa,延性研磨后单晶蓝宝石表面划痕深度的分布情况较好,分散性小,研磨后的表面发生了位错滑移变形.  相似文献   

7.
力平衡模式下半球谐振陀螺正交误差控制   总被引:3,自引:0,他引:3  
针对力平衡半球谐振陀螺的正交漂移问题,对半球谐振陀螺的漂移机理进行了理论建模与分析。引起半球谐振陀螺漂移的主要因素是谐振子的频率裂解以及周向振元衰减时间常数不一致。谐振子振元衰减时间常数不一致主要导致陀螺产生同相漂移;而谐振子频率裂解主要导致陀螺产生正交漂移。同相漂移由于和外界输入角速率所产生的哥氏力相位相同,因此无法从陀螺的输出中剔除,只能通过标定进行补偿。正交漂移则可通过正交控制回路改变谐振子不同方位角上的刚度系数予以消除。为了将谐振子的频率裂解抑制到最小,将陀螺正交漂移项作为正交回路的误差反馈量,实现了基于FPGA的全数字控制方案。实验结果表明,此控制方案可以有效地降低谐振子的频率裂解,抑制半球谐振陀螺的正交漂移。  相似文献   

8.
A method to prepare the carbon nanotubes (CNTs)–Ni–P composite coating with different mass content of CNTs on the surface of 45# steel by electroless plating was proposed. The transmission electron microscopy (TEM) and the scanning electron microscopy (SEM) were used to observe the appearance of the as-prepared CNTs and the CNTs–Ni–P composite coating, and then the roughness of the coating surface was also analyzed by atomic force microscopy (AFM). Furthermore, the wear and friction behavior of the CNTs–Ni–P composite coating were investigated under oil-lubricated condition, Due to the self-lubrication property and the unique antifriction structure, CNTs can greatly improve the wear resistance of the CNTs–Ni–P composite coating, where the wear resistance of the CNTs–Ni–P composite coating is optimized with the intermediate mass content of 2 kg/m3 CNTs.  相似文献   

9.
Integrated information on ultrastructural surface texture and chemistry increasingly plays a role in the biomedical sciences. Light microscopy provides access to biochemical data by the application of dyes. Ultrastructural representation of the surface structure of tissues, cells, or macromolecules can be obtained by scanning electron microscopy (SEM). However, SEM often requires gold or coal coating of biological samples, which makes a combined examination by light microscopy and SEM difficult. Conventional histochemical staining methods are not easily applicable to biological material subsequent to such treatment. Atomic force microscopy (AFM) gives access to surface textures down to ultrastructural dimensions without previous coating of the sample. A combination of AFM with conventional histochemical staining protocols for light microscopy on a single slide is therefore presented. Unstained cores were examined using AFM (tapping mode) and subsequently stained histochemically. The images obtained by AFM were compared with the results of histochemistry. AFM technology did not interfere with any of the histochemical staining protocols. Ultrastructurally analyzed regions could be identified in light microscopy and histochemical properties of ultrastructurally determined regions could be seen. AFM-generated ultrastructural information with subsequent staining gives way to novel findings in the biomedical sciences. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc.  相似文献   

10.
Systematic nanotribological studies of Cr thin films using nanoscratch and AFM techniques are presented. Constant and ramped loading scratches were made using a Nano Indenter II system at various loads (1mN, 2.5mN and 5mN). Extensive AFM studies of the scratch wear tracks have been performed after scratching. The dependence of the displacement, residual wear depth, percent elastic recovery, and friction coefficient on load in constant load and ramped load tests is compared. Under the same (maximum) load, constant load tests exhibit higher displacements, residual depths and friction coefficients but lower percent elastic recoveries. Detailed AFM observations of the wear tracks indicate that significant differences in lateral deformation accompany the observed displacement differences.  相似文献   

11.
To investigate on the crystalline structure of AISI M2 steel by using tungsten–thorium electrode in electrical discharge machining (EDM) process was studied. Furthermore, the investigation were carried out for finding the value of material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) of tool steel material depending upon three variable input process parameters. On the basis of weight loss, the value of MRR and EWR were calculated at optimized process parameter. Subsequently, surface topography of the processed material were examined through different characterization techniques like scanning electron microscopy (SEM), Optical surface profiler (OSP) and Atomic force microscopy (AFM), respectively. In XRD study, broadening of the peak was observed which confirmed the change in material properties due to the homogeneous dispersion of the particles inside the matrix. Lowest surface roughness and MRR of 0.001208 mg/min was obtained. Minimum surface roughness was obtained 1.12 μm and 2.18427 nm by OSP and AFM study, respectively. Also, minimum EWR was found as 0.013986 mg/min.  相似文献   

12.
In this work, an anti-drift and auto-alignment mechanism is applied to an astigmatic detection system (ADS)-based atomic force microscope (AFM) for drift compensation and cantilever alignment. The optical path of the ADS adopts a commercial digital versatile disc (DVD) optical head using the astigmatic focus error signal. The ADS-based astigmatic AFM is lightweight, compact size, low priced, and easy to use. Furthermore, the optical head is capable of measuring sub-atomic displacements of high-frequency AFM probes with a sub-micron laser spot (~570 nm, FWHM) and a high-working bandwidth (80 MHz). Nevertheless, conventional DVD optical heads suffer from signal drift problems. In a previous setup, signal drifts of even thousands of nanometers had been measured. With the anti-drift and auto-alignment mechanism, the signal drift is compensated by actuating a voice coil motor of the DVD optical head. A nearly zero signal drift was achieved. Additional benefits of this mechanism are automatic cantilever alignment and simplified design.  相似文献   

13.
This study proposes a novel double Hall linear differential sensor and investigates its output and temperature characteristics in detail. Finite element method is used to confirm the effectiveness of the proposed method. A practical, open-loop current sensor circuit is designed and constructed based on dual-mode Hall effect theory. Results show that the quiescent output voltage is significantly reduced, and that the signal amplitude is increased by 99.5%. Moreover, sensitivity is more than 40 mV/mT, linearity is 1.2% full scale, and the zero drift coefficient is 0.033 mV/°C. The differential output model can suppress common mode interference and zero drift. The sensor also exhibits temperature self-compensation and non-linear correction functions.  相似文献   

14.
针对材料纳米压痕硬度的压痕尺寸效应(Indentation size effect,ISE),利用纳米压痕技术测得单晶铝和单晶硅的载荷-压深曲线,获得最大载荷和最大压深,并结合原子力显微镜,获得压痕的三维形貌,计算出压痕的真实残余面积。根据最大压深和残余面积提出了一个新的模型——残余面积最大压深模型,此模型能更好地理解和描述材料硬度的压痕尺寸效应,并与其他几种典型的理论和模型进行了比较和分析。  相似文献   

15.
Ball-shaped atomic force microscope (AFM) tips (ball tips) are useful in AFM metrology, particularly in critical dimension AFM metrology and in micro-tribology. However, a systematic fabrication method for nano-scale ball tips has not been reported. We report that nano-scale ball tips can be fabricated by ion-beam-induced deposition (IBID) of Pt at the free end of multiwall carbon nanotubes that are attached to AFM tips. Scanning electron microscopy and transmission electron microscopy analyses were done on the Pt ball tips produced by IBID in this manner, using ranges of Ga ion beam conditions. The Pt ball tips produced consisted of aggregated Pt nano-particles and were found to be strong enough for AFM imaging.  相似文献   

16.
针对皮下植入式葡萄糖传感器在实际动态监测过程中易受生理环境影响限制测量精度的问题,提出了一种基于单点校准技术优化的实时自调整校准算法实现传感器的信号漂移补偿和灵敏度衰减校正。该方法能够对单点校准过程中的关键参数(灵敏度和电流信号)进行调整从而建立最优模型。用最小二乘方法拟合出模型的初始参数,根据建立的最优模型对在体监测3 d的电流数据进行校准,结果表明,经该方法校准的血糖浓度相对误差在0.01%~6.67%范围内,优于传统单点校准模型的6.36%~16.92%,具有更高的校准精度和实用价值,有效提高了动态血糖监测的准确性。  相似文献   

17.
A novel calibration method is proposed for determining lateral forces in atomic force microscopy (AFM), by introducing an angle conversion factor, which is defined as the ratio of the twist angle of a cantilever to the corresponding lateral signal. This factor greatly simplifies the calibration procedures. Once the angle conversion factor is determined in AFM, the lateral force calibration factors of any rectangular cantilever can be obtained by simple computation without further experiments. To determine the angle conversion factor, this study focuses on the determination of the twist angle of a cantilever during lateral force calibration in AFM. Since the twist angle of a cantilever cannot be directly measured in AFM, the angles are obtained by means of the moment balance equations between a rectangular AFM cantilever and a simple commercially available step grating. To eliminate the effect of the adhesive force, the gradients of the lateral signals and the twist angles as a function of normal force are used in calculating the angle conversion factor. To verify reliability and reproducibility of the method, two step gratings with different heights and two different rectangular cantilevers were used in lateral force calibration in AFM. The results showed good agreement, to within 10%. This method was validated by comparing the coefficient of friction of mica so determined with values in the literature.  相似文献   

18.
We have designed and tested a new, inexpensive, easy-to-make and easy-to-use calibration standard for atomic force microscopy (AFM) lateral force measurements. This new standard simply consists of a small glass fiber of known dimensions and Young's modulus, which is fixed at one end to a substrate and which can be bent laterally with the AFM tip at the other end. This standard has equal or less error than the commonly used method of using beam mechanics to determine a cantilever's lateral force constant. It is transferable, thus providing a universal tool for comparing the calibrations of different instruments. It does not require knowledge of the cantilever dimensions and composition or its tip height. This standard also allows direct conversion of the photodiode signal to force and, thus, circumvents the requirement for a sensor response (sensitivity) measurement.  相似文献   

19.
The interface adhesion of the Cu/Ta/Black Diamond? (SiOC:H, BD, low-k)/Si substrate films stack structure was investigated. During the nanoindentation tests, a series of indentations under varied maximum normal loads of 1–120 mN were carried out. Regular triangular marks were formed on the surface, and the material pileup around the marks was clearly observed. The delamination occurred first at the Cu/Ta interface with the critical normal load of about 3.14 mN. As the normal load increased to about 63.71 mN, the BD layer began to delaminate from the Si substrate, resulted from the propagation of the cracking within BD layer along the BD/Si interface. The failure behaviors of the stack structure during the nanoscratch tests were similar to that during the nanoindentation tests. At the scratch velocity of 500 μm/min, the critical normal loads for Cu/Ta and BD/Si interfaces delamination were around 15.55 and 27.44 mN, respectively. Furthermore, the critical normal loads were decreased with the increase of the scratch velocity. Due to the similarity between the nanoscratch test and the chemical mechanical polishing (CMP) process, these results implied that lower polishing speed was preferred to avoid the interface delamination during the CMP of Cu/low-k interconnect structure.  相似文献   

20.
Evidence is presented here for deposition kinetic energy influences on the wear properties of Au and Cu films deposited by evaporation and sputtering on clean and poly(amidoamine) (PAMAM) dendrimer modified SiO x substrates. Ramped load nanoscratch tests show increased resistance to wear in the presence of the dendrimer monolayer. Nanoscratch profiles indicate that the critical load to failure (scratch bearing capacity) is increased in the presence of a dendrimer interlayer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis of the wear tracks show that following film failure plowing is the predominant mechanism of wear for sputtered or evaporatively deposited Au. No obvious changes in the wear properties (a pure cutting mechanism) of Cu thin films are observed upon changing the kinetic energy of the incoming metal.  相似文献   

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