Influence of flowing parameter of magnetorheological polishing fluids (MRPFs) on the quality of processing polycrystalline glass ceramics

2011 ◽  
Vol 23 (9) ◽  
pp. 959-962 ◽  
Author(s):  
Gennadi Gorodkin ◽  
Zoya Novikova
Keyword(s):  
Glass Ceramics ◽  
Root Mean Square Roughness ◽  
Magnetorheological Finishing ◽  
Abrasive Particles ◽  
Atomic Force ◽  
Finishing Process ◽  
Surface Measurements ◽  
Magnetorheological Polishing ◽  
Diamond Abrasive

The study of rheological characteristics for two types of magnetorheological polishing fluids (MRPFs), MRPF-1 based on cerium oxide abrasive particles and MRPF-2 based on nano-diamond abrasive particles, was carried out. Experiments on polishing of a polycrystalline sitall laser mirror substrates with these fluids using magnetorheological finishing process were executed. The surface structure of the samples after the polishing was investigated with the atomic force microscope. The results of surface measurements for the samples under the study polished with both MRPF-1 and MRPF-2 fluids are reported in comparison with the existed data obtained from a regular pitch polishing method. The lowest root-mean-square roughness of 0.2–0.4 nm was obtained for the samples polished with MRPF-2.

scholarly journals Research on The Bonding Properties of Vitrified Bonds With Porous Diamonds and The Grinding Performance of Porous Diamond Abrasive Tools

2021 ◽  
Author(s):  
Jianwei LI ◽  
Wenjun FANG ◽  
Long WAN ◽  
Xiaopan LIU ◽  
Weida HU ◽  
...  
Keyword(s):  
Wafer Surface ◽  
Processing Efficiency ◽  
Abrasive Particles ◽  
Bonding Properties ◽  
New Type ◽  
Vitrified Bond ◽  
Abrasive Tools ◽  
Grinding Efficiency ◽  
Diamond Abrasive

Abstract Ordinary diamond presents the disadvantages of poor self-sharpening and concentrated grinding stress when it is used as an abrasive. Moreover, this kind of diamond cannot be well wetted by the vitrified bond, resulting in a lower holding force of the binder to the abrasives (i.e., the diamond is easy to detach from the binder matrix during grinding). These comprehensive factors not only reduce the surface quality of the processed workpiece, but also hinder the processing efficiency. In order to solve these problems, a new type of porous diamond with high self-sharpening properties was prepared using a thermochemical corrosion method in this study. Our results showed a great improvement in pore volume and specific surface area of the porous diamond compared with ordinary diamond abrasive particles, and the holding force and wettability of vitrified bond to the porous diamond abrasive particles were also improved. Compared with ordinary diamond abrasive tools, porous diamond abrasive tools showed a 29.6% increase in grinding efficiency, a 15.5% decreased in grinding ratio, a 27.5% reduction in workpiece surface roughness, and the scratches on the silicon wafer surface were reduced and refined.

Experimental Trial of Fullerene Wheel Fabrication

2008 ◽  
Vol 389-390 ◽  
pp. 61-66
Author(s):  
Takeshi Tanaka
Keyword(s):  
Silicon Wafer ◽  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Diamond Wheel ◽  
Polishing Process ◽  
Atomic Force ◽  
Finishing Process ◽  
Atomic Force Microscope Observation ◽  
Chemical Mechanical Polishing Process ◽  
Diamond Abrasive

The purpose of this study is to fabricate a wheel using fullerenes with nano-scaled particles, and to investigate the polishing performance of fullerene wheel. A super smooth surface was formed on a silicon wafer by polishing the wafer with metal-bonded diamond wheels using a diamond abrasive grit of 0-0.125 μm and fullerenes with a diameter of 0.7 nm. We used two kinds of metal-bonded diamond wheels for pre-polishing and a metal-bonded fullerene wheel for the finishing process. Though the surface roughness after polishing with the fullerene wheel was almost equal to that obtained by polishing with the metal-bonded diamond wheel using diamond abrasive grit of 0-0.125 μm, the chemical-mechanical polishing process was clarified by AFM (atomic force microscope) observation when we used a metal-bonded fullerene wheel with 5wt% KOH (potassium hydroxide) solution. The greater number of smoothed portions on the surface of the silicon wafer indicated that the fullerenes provided the same polishing ability as that of the abrasive grit.

Some Investigations Into Magnetorheological Finishing (MRF) of Hard Materials

2009 ◽  
Author(s):  
V. K. Jain ◽  
Pankaj Singh ◽  
Puneet Kumar ◽  
Ajay Sidpara ◽  
Manas Das ◽  
...  
Keyword(s):  
Surface Finish ◽  
Magnetorheological Finishing ◽  
Abrasive Particles ◽  
Hard Materials ◽  
Proposed Model ◽  
Finishing Process ◽  
Abrasive Finishing ◽  
Finishing Processes ◽  
Polishing Fluid ◽  
Magnetorheological Polishing Fluid

Magnetorheological finishing (MRF) process is one of the fine abrasive finishing processes used to get better surface finish on a semi finished part. The present work is aimed at investigating the effectiveness and validity of magnetorheological finishing process and finding out the process parameters (such as finishing time, rotational speed of carrier wheel, abrasive concentration, and working gap) and their effectiveness on surface finish characteristics. MRF process is applied on brass and nonmagnetic stainless steel workpieces which were initially finished by the grinding process. The results of experiments were statistically analyzed by response surface methodology (RSM) to form an empirical model for the responses generated during the process. Also, an attempt has been made to model and simulate the finishing operation in MRF process. Apart from this, the micro structure of the mixture of magnetic and abrasive particles in magnetorheological polishing fluid (MR Fluid) has been proposed. Thereafter the normal force on the abrasive particles is calculated from the applied magnetic field and a model for the prediction of surface roughness has also been presented. Finally, theoretical results calculated using the proposed model, have been compared with the experimental results to validate the model developed.

Magnetorheological Finishing (MRF) of a Freeform Non-magnetic Work Material

2015 ◽  
Vol 15 (3) ◽  
pp. 249-256
Author(s):  
Laxmi Narayan Pattanaik ◽  
Himanshu Agarwal
Keyword(s):  
Surface Finish ◽  
Mesh Size ◽  
Magnetorheological Finishing ◽  
Mr Fluid ◽  
Abrasive Particles ◽  
Finishing Process ◽  
Set Up ◽  
Complicated Geometries ◽  
Flexible Magnetic Abrasive Brush ◽  
Precision Finishing

AbstractOne of the newly developed methods for obtaining super-finished shiny surfaces for non-magnetic freeform jobs is magnetorheological finishing (MRF). MRF is an advanced finishing process in which the grinding force is controlled by magnetic field. The material removal in MRF is governed by the magnetorheological (MR) fluid which mainly consists of carbonyl iron (CI), abrasive particles, carrier fluids and additives. It is a precision-finishing process that can finish complicated geometries or difficult-to-approach regions. MRF process is capable of giving nanometre-scale surface finish. The process makes use of an MR fluid as a tool that acts as a flexible magnetic abrasive brush that provides finishing action. The relative motion between the finishing medium and the work can be obtained either by rotating the work, rotating the finishing medium or both. In the present paper, a set-up has been developed for MRF application using a pillar-drilling machine. Experiments were conducted to finish freeform jobs of copper alloy using the developed process. The effects of various process parameters, viz composition of the MR fluid, rotational speed of work and vessel containing MR fluid, mesh size of abrasives on surface finish, were explored.

TRIBOLOGICAL ASPECTS OF DIAMOND-ABRASIVE PROCESSING OF SILICON CARBIDE PLATES

2020 ◽  
Author(s):  
Sergey Bishutin ◽  
Sergey Alehin
Keyword(s):  
Silicon Carbide ◽  
Electron Microscope ◽  
Brittle Fracture ◽  
Experimental Studies ◽  
Surface Layers ◽  
Abrasive Particles ◽  
Tribological System ◽  
Diamond Abrasive ◽  
Scanning Electron

The article considers diamond-abrasive grinding of silicon carbide plates as a tribological system in order to increase the productivity and quality of this processing, as well as to substantiate the directions of its improvement. The process of removing material from the workpiece is considered as a result of abrasive wear of the silicon carbide plate on the lap with loose abrasive. Based on the hypothesis of F. Preston, a dependence was obtained for calculating the rate of removal of material removed during processing from the surface of the workpiece. The results of experimental studies of the productivity and quality of processing are presented. Attention is paid to the formation of surface layers of silicon carbide plates by introducing abrasive particles into the workpiece, causing the formation of multidirectional microcracks and the removal of material mainly as a result of brittle fracture. The results of experimental studies of the state of surface layers using a digital 3-D microscope VHX-1000E, a scanning electron microscope Jeol JSM 6610 and a profiler-profilometer "Mahr GmbH" Based on the research results, recommendations were formulated to improve the efficiency of diamond-abrasive processing of silicon carbide plates.

The Reactive Formation of Diblock Copolymer at a Polymer/Polymer Interface and its Effect on Interfacial Structure

2000 ◽  
Vol 629 ◽  
Author(s):  
Jonathan S. Schulze ◽  
Timothy P. Lodge ◽  
Christopher W. Macosko
Keyword(s):  
Molecular Weight ◽  
Interfacial Structure ◽  
Root Mean Square Roughness ◽  
Radius Of Gyration ◽  
Interfacial Region ◽  
Force Microscopy ◽  
Amino Terminal ◽  
Polymer Interface ◽  
Atomic Force ◽  
Time Required

ABSTRACTThe reaction of perdeuterated amino-terminal polystyrene (dPS-NH2) with anhydrideterminal poly(methyl methacrylate) (PMMA-anh) at a PS/PMMA interface has been observed with forward recoil spectrometry (FRES). Bilayer samples were constructed by placing thin films of PS containing ∼8.5 wt % dPS-NH2 on a PMMA-anh layer. Significant reaction was observed only after annealing the samples at 174°C for several hours, a time scale at least two orders of magnitude greater than the time required for the dPS-NH2 chains to diffuse through the bulk PS layer. The topography of the interfacial region as copolymer formed was measured using atomic force microscopy (AFM). Roughening of the PS/PMMA interface was observed to varying degrees in all annealed samples. Furthermore, the extent of this roughening was found to depend on the PS matrix molecular weight. Reaction in the samples with a high molecular weight PS matrix resulted in a root mean square roughness approximately equal to the radius of gyration Rg of the copolymer. However, approximately twice as much roughening was observed in the low molecular weight PS matrix. This study reveals how the molecular weight of one of the phases can affect the rate of reaction at a polymer/polymer interface.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

Comparative Surface Imaging Study of Multifocal Diffractive Intraocular Lenses

2021 ◽  
Author(s):  
Hyeck Soo Son ◽  
Jung Min Lee ◽  
Ramin Khoramnia ◽  
Chul Young Choi
Keyword(s):  
Imaging Study ◽  
The Other ◽  
Intraocular Lenses ◽  
Optical Surface ◽  
Diffractive Optic ◽  
Atomic Force ◽  
Acceptable Range ◽  
Different Types ◽  
Concentric Pattern

Abstract Purpose To analyse and compare the surface topography and roughness of three different types of diffractive multifocal IOLs. Methods Using scanning electron microscope (SEM, Inspect F, 5.0 KV, maximum magnification up to 20,000) and atomic force microscope (AFM, Park Systems, XE-100, non-contact, area profile comparison, 10 × 10 µm, 40 × 40 µm), the surface quality of the following diffractive IOLs was studied: the AcrySof IQ PanOptix (Alcon, USA), the AT LARA 829MP (Carl Zeiss Meditec, Germany), and Tecnis Symfony (Johnson&Johnson Vision, USA). The measurements were made over three representative areas (central non-diffractive optic, central diffractive optic, and diffractive step) of each IOL. Roughness profile in terms of mean arithmetic roughness (Ra) and root-mean-squared roughness (Rq) values were obtained and compared statistically. Results In SEM examination, all IOLs showed a smooth optical surface without any irregularities at low magnification. At higher magnification, Tecnis Symfony showed unique highly regular, concentric, and lineate structures in the diffractive optic area which could not be seen in the other studied diffractive IOLs. The differences in the measured Ra and Rq values of the Tecnis Symfony were statistically significant compared to the other models (p < 0.05). Conclusion Various different topographical traits were observed in three diffractive multifocal IOLs. The Ra values of all studied IOLs were within an acceptable range. Tecnis Symfony showed statistically significant higher surface Ra values at both central diffractive optic and diffractive step areas. Furthermore, compared to its counterparts, Tecnis Symfony demonstrated highly ordered, concentric pattern in its diffractive surfaces.

Experimental investigation into polishing of monocrystalline silicon wafer using double-disc chemical assisted magnetorheological finishing process

2021 ◽  
pp. 095440622098384
Author(s):  
Mayank Srivastava ◽  
Pulak M Pandey
Keyword(s):  
Surface Roughness ◽  
Silicon Wafer ◽  
Flow Rate ◽  
Silicon Wafers ◽  
Monocrystalline Silicon ◽  
Slurry Flow ◽  
Magnetorheological Finishing ◽  
Finishing Process ◽  
Process Factors ◽  
Slurry Flow Rate

In the present work, a novel hybrid finishing process that combines the two preferred methods in industries, namely, chemical-mechanical polishing (CMP) and magneto-rheological finishing (MRF), has been used to polish monocrystalline silicon wafers. The experiments were carried out on an indigenously developed double-disc chemical assisted magnetorheological finishing (DDCAMRF) experimental setup. The central composite design (CCD) was used to plan the experiments in order to estimate the effect of various process factors, namely polishing speed, slurry flow rate, percentage CIP concentration, and working gap on the surface roughness ([Formula: see text]) by DDCAMRF process. The analysis of variance was carried out to determine and analyze the contribution of significant factors affecting the surface roughness of polished silicon wafer. The statistical investigation revealed that percentage CIP concentration with a contribution of 30.6% has the maximum influence on the process performance followed by working gap (21.4%), slurry flow rate (14.4%), and polishing speed (1.65%). The surface roughness of polished silicon wafers was measured by the 3 D optical profilometer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were carried out to understand the surface morphology of polished silicon wafer. It was found that the surface roughness of silicon wafer improved with the increase in polishing speed and slurry flow rate, whereas it was deteriorated with the increase in percentage CIP concentration and working gap.

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