Surface Finishing for Biomaterials: Application of the Elid Grinding Method

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1395-1400 ◽  
Author(s):  
Masayoshi Mizutani ◽  
Jun Komotori ◽  
Jin Nagata ◽  
Kazutoshi Katahira ◽  
Hitoshi Ohmori
Keyword(s):  
Oxide Layer ◽  
Ground Surface ◽  
Surface Finishing ◽  
Oxide Layers ◽  
Elid Grinding ◽  
Grinding Method ◽  
Transmission Electron ◽  
Finished Surface ◽  
Thick Oxide Layer

Conventional biomaterials, such as titanium alloys, require enhanced chemical stability and wear resistance, which are dependent on the quality of the surficial oxide layer. However, it is very difficult to produce a sufficiently homogenous oxide layer by polishing using isolation abrasive alone. In our previous study, we proposed a new electrical grinding method (ELID grinding). The process improves oxide formation on the finished surface, resulting in finished surfaces with very thick and potentially stable oxide layers. In this study, to ensure the fabrication of surface with desirable characteristics for biomaterials, three types of specimens, which were processed with different surface finishing methods were prepared. Processed surfaces were analyzed by using an Energy Dispersive X-ray analyzer (EDX). To measure the thickness of surface oxide layers, detailed observation were performed by using a Transmission Electron Microscope (TEM). Although the ELID ground surface shows a higher value of surface roughness, excellent corrosion resistance was observed as compared with the samples finished by polishing. This is because of the formation of a thick oxide layer on the finished surface by ELID grinding. Consequently, ELID grinding appears to offer significant future promise for use in biomaterials and other engineering components subjected to the corrosion process.

Fine ELID Grinding on the Symmetric Paraboloidal Mirror of Quartz

2007 ◽  
Vol 339 ◽  
pp. 11-15
Author(s):  
J. Guo ◽  
Hitoshi Ohmori ◽  
Shinya MORITA ◽  
Y. Watanabe ◽  
Yoshihiro Uehara ◽  
...  
Keyword(s):  
Ground Surface ◽  
High Hardness ◽  
Optical Devices ◽  
Coating Process ◽  
Form Error ◽  
Elid Grinding ◽  
Grinding Method ◽  
Finished Surface ◽  
New Type ◽  
Diamond Abrasive

Quartz has excellent optical properties and thus it is often used as the material of mirror and lens. However, it is almost impossible to be machined by cutting due to its brittle and high hardness. Grinding is a common method for machining quartz. One of the authors designed a new type of a paraboloidal mirror of quartz for the neutron optical devices. The fabrication process of this mirror was investigated in this experiment. A jig with two grooves of 90 degrees was made and two workpieces were stuck on the jig using the wax melt at about 60 degrees centigrade. The two workpieces were first ground applying ELID (electrolytic in-process dressing) grinding method with #325 and #1200 cast iron bonding diamond abrasive wheels. Then the ground surface was polished with CeO2 slurry. The finished surface roughness was Ra2.0nm and rms2.4nm and its form error about 2μm. After coating process, its properties of focusing neutron beam were measured. The results were that the reflecting rate was 42%, gain 1.9 and 2.3mm×10.1mm beam focused to 1.6mm×2.1mm.

Effect of Anodizing in Surface Finishing on Speed Boat Impeller Made of Aluminum

2014 ◽  
Vol 896 ◽  
pp. 253-256 ◽  
Author(s):  
Soekrisno Soekrisno ◽  
Budy Anggoro
Keyword(s):  
Oxide Layer ◽  
High Speed ◽  
Sea Water ◽  
Pure Aluminum ◽  
Testing Machine ◽  
Wear Testing ◽  
Surface Finishing ◽  
Hardness Tester ◽  
Surface Increase

Aluminum alloy have been used for machine components in many functions and sizes. Every part need to be strong and long life, but when wear should be considered, then one have to hardened the surface, usually the harder the surface, the longer the life. One of the components that mention above is speed boat impeller. The sea water may cause the surface of the impeller eroded. Base on that reason the impeller should be hardened to extend its life. The anodizing process was chosen to improve the surface quality of the aluminum to reduce abrasion/erosion. Aluminum is a special material, other metal will be damaged or being worse when corroded, but Aluminum oxide is harder then the pure aluminum. In this process we use H2SO4solution and the range of the anodizing temperature were changed gradually. This process was using single electrical force 20 Volt, to serve the anodizing for several minutes. All specimens finally were tested in Vickers micro hardness tester, also in Ogoshi High Speed Universal Wear Testing Machine. The last but not least, we cuts the specimens to see the thickness of the oxide layer by SEM. The result shows that for both hardness and wear, the quality of the surface increase with the increase of the solution of H2SO4, and also better for longer anodizing time. The thickness of the oxide layer was measured using SEM, at five places, and the average of the thickness is 2.662 mm.

scholarly journals Microstructure of Surface and Subsurface Layers of a Ni-Ti Shape Memory Microwire

2009 ◽  
Vol 15 (1) ◽  
pp. 62-70 ◽  
Author(s):  
H. Tian ◽  
D. Schryvers ◽  
S. Shabalovskaya ◽  
J. Van Humbeeck
Keyword(s):  
Oxide Layer ◽  
Shell Structure ◽  
Core Shell ◽  
Strong Temperature Dependence ◽  
Transmission Electron ◽  
Subsurface Layers ◽  
Thick Oxide Layer ◽  
Core Shell Structure ◽  
Cold Worked ◽  
Microscopy Techniques

AbstractThe microstructure of a 55 μm diameter, cold-worked Ni-Ti microwire is investigated by different transmission electron microscopy techniques. The surface consists of a few hundred nanometer thick oxide layer composed of TiO and TiO2with a small fraction of inhomogeneously distributed Ni. The interior of the wire has a core-shell structure with primarily B2 grains in the 1 μm thick shell, and heavily twinned B19′ martensite in the core. This core-shell structure can be explained by a concentration gradient of the alloying elements resulting in a structure separation due to the strong temperature dependence of the martensitic start temperature. Moreover, in between the B2 part of the metallic core-shell and the oxide layer, a Ni3Ti interfacial layer is detected.

Oxide Layer Formation by Micro-Arc Oxidation on Structurally Modified Al-Si Alloys and Applications for Large-Sized Articles Manufacturing

2008 ◽  
Vol 59 ◽  
pp. 204-208 ◽  
Author(s):  
Mikhail M. Krishtal
Keyword(s):  
Oxide Layer ◽  
Layer Growth ◽  
Oxidation Products ◽  
Cylinder Block ◽  
Initial Structure ◽  
Near Surface ◽  
Oxide Layers ◽  
Micro Arc Oxidation ◽  
High Level

The effect of the shape, size and kind of distribution of the silicon inclusions in Al-Si alloys of hypoeutectic, eutectic, and hypereutectic compositions (6–22 % Si) on the quality of oxide layer formed by micro-arc oxidation (MAO) is studied. The hitherto unknown phenomenon of oxide layer growth inhibition by the silicon particles under MAO is discovered and researched. The filling of near-surface pores by oxidation products in MAO process is observed also. The discovered ability to increase the properties of oxide layers obtained by the MAO due to prior directed modifica¬tion of the initial structure provides the good quality of oxide layers for aluminium alloys with high level of silicon content up to hypereutectic compositions of Al-Si alloys. The physical opportunity to get the high quality oxidized layers by MAO on structurally modified Al-Si alloys is confirmed for large-sized Al-Si alloys castings (including cylinder block for engine).

The ELID Grinding of CoCrMo Alloy Bioprosthesis and the Formation Mechanism of its Corrosion-Resistant Oxide Layer

2018 ◽  
Vol 934 ◽  
pp. 140-144 ◽  
Author(s):  
Ji Cai Kuai ◽  
Cheng Ran Jiang ◽  
Jiang Wei Wang ◽  
Dmitrii V. Ardashev
Keyword(s):  
Oxide Layer ◽  
Formation Mechanism ◽  
Low Cost ◽  
Medical Field ◽  
Cocrmo Alloy ◽  
Corrosion Resistant ◽  
Elid Grinding ◽  
Grinding Method ◽  
Biological Environment

CoCrMo alloy is widely used in the medical field to make Biomedical prosthesis,But it is difficult to process resulting in the high cost of Biomedical prosthesis, Find an efficient and low-cost processing method has become a problem to be solved. In this paper, CoCrMo alloy Biomedical prosthesis were fabricated by Electrolytic In-process Dressing grinding. We studied the ELID grinding performance, grinding force, surface quality and the formation mechanism of Corrosion-resistant oxide layer of CoCrMo alloy by using dynamometer, roughness tester, XRD and SEM. It is proposed that the ELID grinding method forms an oxide layer on the surface of the prosthesis, which increases the corrosion resistance and biocompatibility of the prosthesis so that it can be better adapt to the biological environment in vivo. It was further confirmed that the ELID grinding method is an effective method for manufacturing CoCrMo Alloy Bioprosthesis.

Nanoprecision Micromechanical Fabrication

2008 ◽  
Vol 2 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Hitoshi Ohmori ◽  
◽  
Weimin Lin ◽  
Yoshihiro Uehara ◽  
Yutaka Watanabe ◽  
...  
Keyword(s):  
Surface Quality ◽  
High Surface ◽  
Surface Grinding ◽  
Mirror Surface ◽  
Optical Components ◽  
High Surface Quality ◽  
Elid Grinding ◽  
Grinding Method ◽  
Electrolytic Dressing

ELID grinding is a method that realizes high quality mirror surface grinding in the nanometer order by use of electrolytic dressing metal bonded wheels consisting of fine abrasives. Currently, ELID grinding is increasingly being applied as an ultraprecision grinding method to achieve desired surface roughness, high surface accuracy, high surface quality, and high grinding performance. This paper introduces the ELID grinding and discusses some applications of ELID grinding to mirror surface grinding. For ultraprecision optical components, ultra fine smooth surface quality of sub-nanometer or sub-angstrom in Ra may be required. To satisfy these requirements, ultraprecision on machine measurement system had been developed. Synergistic the nano precision mechanical method, nano precision measurement method with nano resolution machine, the ultraprecision components can successful to fabricate.

ELID Grinding Characteristics and Surface Analysis for Micro Fabrication of Advanced Ceramics

2007 ◽  
Vol 339 ◽  
pp. 483-489 ◽  
Author(s):  
Kazutoshi Katahira ◽  
Hitoshi Ohmori
Keyword(s):  
Surface Hardness ◽  
Ground Surface ◽  
Ceramic Materials ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Spherical Lens ◽  
Elid Grinding ◽  
Grinding Method ◽  
Centerless Grinding ◽  
Ground Surface Roughness

The present paper describes the highly efficient and precise ELID grinding method and presents a discussion on the ELID grinding process and the grinding characteristics of several kinds of ceramic materials. The following conclusions are obtained; (1) Good ground surface roughness and accuracy are achieved using the #4000 metal-bonded grinding wheel in through-feed centerless grinding for ZrO2 optical fiber ferrules. (2) Efficient and precise grinding of spherical lens molds with cup wheels using the ELID CG-grinding process was proposed and tested in the present study. (3) The ELID grinding method can be used to fabricate machined surfaces exhibiting desirable characteristics for hard AlN ceramics. The ELID ground AlN demonstrated a surface hardness and sliding characteristics that were superior to those of the polished series. These advantages may be attributable to the diffusion phenomenon of the oxygen element produced by the ELID grinding.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

The annealed (0001) α-alumina surface and its influence on thin-film growth

1995 ◽  
Vol 53 ◽  
pp. 336-337
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Film Growth ◽  
Thin Film Growth ◽  
Energy Calculations ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Low Energy Electron ◽  
Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

Methods to Monitor and Improve the Performance of Specimen Holders for Transmission Electron Cryomicroscopy

1996 ◽  
Vol 54 ◽  
pp. 454-455
Author(s):  
B. L. Armbruster ◽  
B. Kraus ◽  
M. Pan
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Beam Irradiation ◽  
Quality Of Data ◽  
Electron Cryomicroscopy ◽  
Thermal Equilibration ◽  
Transmission Electron ◽  
Electron Microscopes

One goal in electron microscopy of biological specimens is to improve the quality of data to equal the resolution capabilities of modem transmission electron microscopes. Radiation damage and beam- induced movement caused by charging of the sample, low image contrast at high resolution, and sensitivity to external vibration and drift in side entry specimen holders limit the effective resolution one can achieve. Several methods have been developed to address these limitations: cryomethods are widely employed to preserve and stabilize specimens against some of the adverse effects of the vacuum and electron beam irradiation, spot-scan imaging reduces charging and associated beam-induced movement, and energy-filtered imaging removes the “fog” caused by inelastic scattering of electrons which is particularly pronounced in thick specimens.Although most cryoholders can easily achieve a 3.4Å resolution specification, information perpendicular to the goniometer axis may be degraded due to vibration. Absolute drift after mechanical and thermal equilibration as well as drift after movement of a holder may cause loss of resolution in any direction.

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