Improving the Sediment Stability of Fluid Magnetic Abrasives Based on Nanometer SiO2

2010 ◽  
Vol 135 ◽  
pp. 159-163
Author(s):  
Huan Wu Sun ◽  
Wei Yi Chen

The fluid magnetic abrasives (FMA) are a new type of precision finishing abrasives which are developed on the basis of the phase transition phenomenon caused by magnetic field. The sediment stability and agglomerative stability are significant characteristics of FMA, and have a great impact on the finishing capabilities and the final surface roughness value. In order to improve the stability of FMA, a new ingredient based on nanometer SiO2 is proposed, the preparation method and the experimental results are also discussed in this paper.

2009 ◽  
Vol 416 ◽  
pp. 54-60
Author(s):  
Huan Wu Sun ◽  
Shi Chun Yang

The fluid magnetic abrasives (FMA) are a new type of precision finishing abrasives which are developed on the basis of the phase transition phenomenon caused by magnetic field. The rheological effect of FMA is the basis to achieve its finishing function, and has a great impact on the finishing capabilities and the final surface roughness. In order to get a better understanding of FMA finishing mechanism, the rheological effect models of FMA are deduced for the first time, the simulations and the experimental results are discussed as well in this paper.


2008 ◽  
Vol 392-394 ◽  
pp. 45-49
Author(s):  
Huan Wu Sun ◽  
Shi Chun Yang

The fluid magnetic abrasives (FMA) are a new type of precision finishing abrasives, which can be used to finish the work-pieces with intricate or complex shape to a quite low surface roughness value. As a key parameter, the material removal rate has a great impact on the finishing capabilities and the final surface roughness. In order to get a better understand of FMA removal mechanism, the numerical analyses was used to simulate the shearing stress field and velocity distribution. The experimental results are discussed as well in this paper.


Author(s):  
Huanwu Sun ◽  
Shichun Yang

The fluid magnetic abrasive (FMA) is a new type of precision finishing abrasives, which is typically prepared by dispersing the magnetic particles, nonmagnetic abrasives, surfactants in a non-magnetizable carrier liquid. As the functional particles, the characteristics of magnetic particles have a great impact on the properties of FMA. In our experiment, the micron-sized carbonyl-iron (CI) particles (typical size: 3 μm–5 μm) are found to be ideally suited for the preparation of FMA. In this paper, the selections of micron-sized carbonyl-iron particles suitable for the FMA, the preparation techniques, the finishing mechanism and finishing process are presented. Some key parameters of FMA that may affect the finishing efficiency and the final surface roughness are analyzed theoretically. The experimental results are discussed as well in this paper.


2012 ◽  
Vol 522 ◽  
pp. 3-7
Author(s):  
Wei Dong Li ◽  
Ming Lv

The fluid magnetic abrasive (FMA) is a new type of intelligent material. The fluid magnetic abrasive (FMA) has typical liquid characteristics, when there is no external magnetic field around it. But when a strong magnetic field is applied, the viscosity of it will increase more than 100 times within a few milliseconds, and it will show the characteristics those are resemble to solid's. We call this feature as rheological property, of which because the workpiece can be finished by fluid magnetic abrasive (FMA). On base of researching on the micro-structure of fluid magnetic abrasive (FMA), the experiments and results are presented in this paper.


2010 ◽  
Vol 455 ◽  
pp. 211-215 ◽  
Author(s):  
H. Zhang ◽  
W.D. Li

The fluid magnetic abrasive (FMA) is a new type of precision finishing abrasives. The workpiece can be finished by fluid magnetic abrasive (FMA) because of its rheological property. On base of researching on the micro-structure of fluid magnetic abrasive (FMA), this paper analyzed the finishing mechanism. And the experiments and results are presented as well in this paper.


2009 ◽  
Vol 69-70 ◽  
pp. 143-147 ◽  
Author(s):  
Yan Hua Zou ◽  
Takeo Shinmura

This paper proposes a new magnetic field assisted machining process using a magnetic machining jig (permanent magnet tool) to finish the internal surface of thick tubing 5~30 mm in thickness. Because the magnetic machining jig consists of permanent magnets, it can generate a higher magnetic force (finishing force) than conventional magnetic abrasives, and makes possible the internal finishing of thick non-ferromagnetic tubing. First, the principle and the feature of this process were examined. It was compared that the difference of the mechanism of using the conventional magnetic abrasives and magnetic machining jig (magnet tool) was clarified. Next, a processing unit and magnetic machining jig were made, and the processing unit was set on a lathe machine. An experiment was performed on a thick SUS304 stainless steel tubing 5 mm in thickness. In this study, it was clarified that this processing method can improve the roundness of the inside tubing while improving the surface roughness. The results showed that the initial surface roughness of 6.5 μm Ra can be improved to 0.06 μm Ra, and the roundness of the inside tubing can be improved from 187 μm to 89 μm.


1995 ◽  
Vol 396 ◽  
Author(s):  
L. A. Gea ◽  
L. A. Boatner ◽  
J. D. Budai ◽  
R. A. Zuhr

AbstractIn this work, we report the formation of a new type of active or “smart” surface that is produced by ion implantation and thermal processing. By co-implanting vanadium and oxygen into a single-crystal sapphire substrate and annealing the system under appropriate conditions, it was possible to form buried precipitates of vanadium dioxide that were crystallographically oriented with respect to the host AI2O3 lattice. The implanted VO2 precipitate system undergoes a structural phase transition that is accompanied by large variations in the optical transmission which are comparable to those observed for thin films of VO2 deposited on sapphire. Co-implantation with oxygen was found to be necessary to ensure good optical switching behavior.


2005 ◽  
Vol 2005 (23) ◽  
pp. 3727-3737 ◽  
Author(s):  
Jitender Singh ◽  
Renu Bajaj

Effect of an axially applied magnetic field on the stability of a ferrofluid flow in an annular space between two coaxially rotating cylinders with nonaxisymmetric disturbances has been investigated numerically. The critical value of the ratioΩ∗of angular speeds of the two cylinders, at the onset of the first nonaxisymmetric mode of disturbance, has been observed to be affected by the applied magnetic field.


Data ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Evgeny Mikhailov ◽  
Daniela Boneva ◽  
Maria Pashentseva

A wide range of astrophysical objects, such as the Sun, galaxies, stars, planets, accretion discs etc., have large-scale magnetic fields. Their generation is often based on the dynamo mechanism, which is connected with joint action of the alpha-effect and differential rotation. They compete with the turbulent diffusion. If the dynamo is intensive enough, the magnetic field grows, else it decays. The magnetic field evolution is described by Steenbeck—Krause—Raedler equations, which are quite difficult to be solved. So, for different objects, specific two-dimensional models are used. As for thin discs (this shape corresponds to galaxies and accretion discs), usually, no-z approximation is used. Some of the partial derivatives are changed by the algebraic expressions, and the solenoidality condition is taken into account as well. The field generation is restricted by the equipartition value and saturates if the field becomes comparable with it. From the point of view of mathematical physics, they can be characterized as stable points of the equations. The field can come to these values monotonously or have oscillations. It depends on the type of the stability of these points, whether it is a node or focus. Here, we study the stability of such points and give examples for astrophysical applications.


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