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Improved Carbon Materials for Nanomanufacturing Applications
Published in Ahmed Busnaina, Nanomanufacturing HANDBOOK, 2017
Patrick Lemoine, John Paul Quinn, Pagona Papakonstantinou, Paul Maguire, James McLaughlin
Such a Raman spectrum obtained at 514 nm is shown in Figure 12.8. After subtraction of the luminescence background, the spectrum can be fitted with the D and G band, usually found in a-C:H spectra. The broad spectral shape is similar to that obtained for a-C:H films grown by PECVD. The ID/IG intensity ratio of the EBID sample is much higher (0.86 instead of 0.3 to 0.6) than that of the PECVD sample although both samples have a similar G peak position (~1560 cm–1). Moreover, the width of the D peak is much larger for the EBID sample (FWHM ~ 318 cm–1 instead of 200 cm–1). The hardness values measured with the MTS nanoindenter are shown in Table 12.4. Again, these films are somewhat softer than a-C:H grown by PECVD; however, they are much harder than graphite. Overall, these results suggest that EBID carbon is a form of a-C:H. This is also the consensus arising from the literature. Initially, the hydrocarbon molecules adsorbed on the surface are polymerized by the electron beam. At a later stage, this polymeric film is densified and reticulated by preferential displacement of hydrogen, leaving hydrogenated amorphous carbon. Figure 12.9 shows an SEM micrograph of a high-aspect-ratio carbon needle grown by EBID on polycrystalline aluminum.
Smoothed particle hydrodynamics for modeling metal cutting
Published in Angelos P. Markopoulos, J. Paulo Davim, Advanced Machining Processes, 2017
Islam et al. [32] used SPH to model nanomachining of copper in order to better understand the mechanisms involved in nanoscale deformation, and postmachined surface generation. An SPH nanomachining analysis was performed to simulate nanoindentation, using a conical tool, and the predictions were validated against experiments performed on a nanoindenter. The tool was first indented into the workpiece up to the given depth of cut, and then, cutting was performed. After cutting, the tool was withdrawn from the surface leaving a nanomachined surface. The authors reported that the feed force was found to be larger than the cutting component. The developed model captured the cutting and ploughing mechanisms, and it was consistent with the experimental observations. A larger negative rake angle was found to result in more ploughing and in higher residual stresses and strains. The ratio between the cutting and ploughing force components was found to be unaffected by the depth of cut. However, it was significantly affected by the rake angle.
Postprocessing of Dialysis Membranes
Published in Sirshendu De, Anirban Roy, Hemodialysis Membranes, 2017
Again, to understand the methodology of this characterization, it is important to understand the principle of operation of the machine. Nanoindentation is a powerful tool to evaluate mechanical properties (like the ones discussed in Chapter 4 for ultimate tensile strength) at the microscale or nanoscale. The various parameters of materials studied with this instrument are elastic modulus, hardness, viscous parameters, and so on. The advantage of this technology lies in the ability to analyze very small material volumes. The goal in the majority of studies is to extract hardness and elastic modulus of a material from load–displacement measurements. A specified load is applied via a nanoindenter; typical ones are depicted in Figure 6.1. Diamond, which is very hard (and brittle), is a common choice of material for a nanoindenter.
Small-scale deformation behaviour of the AlCoCrFeNi2.1 eutectic high entropy alloy
Published in Philosophical Magazine, 2022
Shailesh Kumar Singh, Govind Kumar, Pokula Narendra Babu, Snehanshu Pal, Saurabh Vashistha, M. S. Azam, Saurabh Dixit
Using the method proposed by Oliver and Pharr [27–29] data obtained from Berkovich indenters can be analyzed. The Berkovich indenter has a total included angle (plane to edge) of 142.31 degree and a half angle of 65.351 degree. Using an aspect ratio of 1:8, the Berkovich indenter is designed to have the same depth to area ratio as the Vickers indenter (micro indentation standard). The generated load-depth curve for each load was analyzed for both phases to determine the material’s indent properties. For each, the specified total time was 75 s. Out of the total time, 30 s were allotted for the loading process, 15 s for dwelling & the remaining 30 s for the unloading part. While working with Berkovich indenter, the standard load-controlled test for indenting the individual sample generally comprised three parts: loading, holding at the peak and unloading. Loading and unloading of trapezoidal loading function lasted for 60 s, and the dwelling part lasted for 15 s with maximum applied load was up to 1000 mN. The nano-indenter is equipped with a high-resolution actuator to force an indenter into the test surface and a high-resolution sensor to continuously measure the resulting penetration.
Effects of Test Parameters on the Frictional Properties of Al/Diamond-Like Carbon Core-Shell Nanostructure-Textured Surfaces
Published in Tribology Transactions, 2022
Colin Phelan, Charles Miller, Josue A. Goss, Christopher Rincon, Ronghua Wei, Min Zou
Nanoscratch experiments were performed using an instrumented nanoindenter in a laboratory environment with a controlled temperature of about 22 °C and a relative humidity of about 50% inside a rubber-sealed acoustic enclosure to produce the following measurements. The nanoindenter detects displacement and both lateral and vertical forces by utilizing a two-axis transducer. The transducer has two three-plate capacitive sensors with electrostatic force actuation and can generate a normal/vertical force resolution of 3 nN, vertical displacement resolution of 0.04 nm, and lateral force resolution of 500 nN.
Lubricating Ability of Magnesium Silicate Hydroxide–Based Nanopowder as Lubricant Additive in Steel–Steel and Ceramic–Steel Contacts
Published in Tribology Transactions, 2020
Hong Guo, Fanghua Chen, Rui Liu, Patricia Iglesias
After the tests, all bearings were cleaned with isopropyl alcohol (99.5%) in an ultrasonic cleaner and dried in air. The inner rings were cut into small pieces with a precise cutting machine and hot mounted. Nanoindentation tests were carried out with a nanoindenter. At least five tests were conducted along the wear track with a maximum depth of 2,000 nm and a surface approaching a velocity of 10 nm/s. SEM and EDS were used to analyze the wear mechanism of the inner ring surfaces and the interface chemical reactions between the inner rings and roller balls.