scholarly journals A Framework for Surface Modification by Electrical Discharge Coating using Variable Density Electrodes

2021 ◽  
Vol 309 ◽  
pp. 01093
Author(s):  
Mohd Yunus Khan ◽  
P. S. Rao ◽  
B.S. Pabla
Keyword(s):  
Surface Modification ◽  
Electrical Discharge ◽  
Variable Density ◽  
Work Piece ◽  
Hard Material ◽  
Metal Powders ◽  
Material Transfer ◽  
Modification Technique ◽  
Polarity Condition ◽  
Surface Modification Techniques

Surface modification is the process of altering physical or chemical characteristics of the work-piece surface. In this paper, various surface modification techniques have been discussed. One of the most appropriate surface modification technique is electrical discharge coating (EDC), in which the hard material is made to deposit onto the work-piece in a state of reverse polarity condition. Different mechanisms of carrying out EDC are presented. Deliberate material transfer takes place by using electrodes or by dispersant of metal powders into the di-electric. A detailed review of the literature on the theme of surface modification through the EDC has been conducted. In last, a framework for conducting surface modification by EDC employing using density electrodes of same material is presented.

scholarly journals An overview of biofunctionalization of metals in Japan

2009 ◽  
Vol 6 (suppl_3) ◽  
Author(s):  
Takao Hanawa
Keyword(s):  
Surface Modification ◽  
Metal Surface ◽  
Surface Composition ◽  
Polyurethane Composite ◽  
Modification Technique ◽  
Composition Structure ◽  
Poly Ethylene ◽  
Surface Modification Techniques ◽  
The Relationship ◽  
Metal Polymer

Surface modification is an important and predominant technique for obtaining biofunction and biocompatibility in metals for biomedical use. The surface modification technique is a process that changes the surface composition, structure and morphology of a material, leaving the bulk mechanical properties intact. A tremendous number of surface modification techniques using dry and wet processes to improve the hard tissue compatibility of titanium have been developed. Some are now commercially available. Most of these processes have been developed by Japanese institutions since the 1990s. A second approach is the immobilization of biofunctional molecules to the metal surface to control the adsorption of proteins and adhesion of cells, platelets and bacteria. The immobilization of poly(ethylene glycol) to a metal surface with electrodeposition and its effect on biofunction are reviewed. The creation of a metal–polymer composite is another way to obtain metal-based biofunctional materials. The relationship between the shear bonding strength and the chemical structure at the bonding interface of a Ti-segmentated polyurethane composite through a silane coupling agent is explained.

Research on Surface Modification Technique by EDM

2010 ◽  
Vol 154-155 ◽  
pp. 1193-1198 ◽  
Author(s):  
Xiao Hai Li ◽  
Yu Fang ◽  
Xin Rong Wang ◽  
Bao Lin Yin
Keyword(s):  
Surface Modification ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
New Method ◽  
Die Steel ◽  
Steel Coating ◽  
Die Surface ◽  
Modification Technique

This paper describes a new method of die surface modification by ordinary Electrical Discharge Machining (EDM) tool. First, the principle of this method is studied. Secondly, the technology and characteristics of the die steel coating are discussed in detail based on lots of experiments, and the results show that the die steel characteristics are improved evidently by using EDM. At last, the technology is applied to the punch die initially, and it can be drawn that the life of the coated punch die is improved evidently compared with the non-coated punch die through the punching test.

Surface modification of a magnesium alloy by electrical discharge coating with a powder metallurgy electrode

2021 ◽  
Vol 63 (4) ◽  
pp. 360-367
Author(s):  
Uthirapathi Elaiyarasan ◽  
Vinaitheerthan Satheeshkumar ◽  
Chinnamuthu Senthilkumar
Keyword(s):  
Surface Roughness ◽  
Surface Modification ◽  
Powder Metallurgy ◽  
Magnesium Alloy ◽  
Electrical Discharge ◽  
Transfer Rate ◽  
Material Transfer ◽  
Coating Characteristics ◽  
Coated Surface ◽  
Pulse On Time

Abstract The present paper elucidates an experimental study on the surface modification of a ZE41 A magnesium alloy by electrical discharge coating (EDC) process with a tungsten carbide-copper (WC-Cu) powder metallurgy (PM) electrode. Investigated EDC parameters were compaction load, current and pulse on time. Measurement of coating characteristics such as material transfer rate (MTR) and surface roughness (Ra) were undertaken on the coated workpiece. As the design of experiment, response surface methodology was applied and analysis of variance (ANOVA) test was completed to study the influence of process parameters. Mathematical models were developed for coating characteristics to optimize the parameters. In this study, the reliability of the regression model is considered satisfactory with a value larger than 99 %. It was found from the study that the current plays a vital role in increasing the material transfer rate and minimizing the surface roughness of the coated surface followed by compaction load and pulse on time. Various studies such as scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were carried out to determine the characteristics of the coated layer. These analyses confirmed the presence of the electrode materials in the coated surface.

Properties and Applications of Modified Bacterial Cellulose-Based Materials

2020 ◽  
Vol 16 ◽  
Author(s):  
Munair Badshah ◽  
Hanif Ullah ◽  
Fazli Wahid ◽  
Taous Khan
Keyword(s):  
Surface Modification ◽  
Bacterial Cellulose ◽  
Degree Of Polymerization ◽  
Biomedical Science ◽  
Hydroxyl Groups ◽  
Market Demand ◽  
Ideal Candidate ◽  
Fibrous Network ◽  
Potential Applications ◽  
Surface Modification Techniques

Background: Bacterial cellulose (BC) is purest form of cellulose as it is free from pactin, lignin, hemicellulose and other active constituents associated with cellulose derived from plant sources. High biocompatibility and easy molding into desired shape make BC an ideal candidate for applications in biomedical field such as tissue engineering, wound healing and bone regeneration. In addition to this, BC has been widely studied for applications in the delivery of proteins and drugs in various forms via different routes. However, BC lacks therapeutic properties and resistance to free movement of small molecules i.e., gases and solvents. Therefore, modification of BC is required to meet the research ad market demand. Methods: We have searched the updated data relevant to as-synthesized and modified BC, properties and applications in various fields using Web of science, Science direct, Google and PubMed. Results: As-synthesized BC possesses properties such as high crystallinity, well organized fibrous network, higher degree of polymerization, and ability of being produced in swollen form. The large surface area with abundance of free accessible hydroxyl groups makes BC an ideal candidate for carrying out surface functionalization to enhance its features. The various reported surface modification techniques including, but not limited to, are amination, methylation and acetylation. Conclusion: In this review, we have highlighted various approaches made for BC surface modification. We have also reported enhancement in the properties of modified BC and potential applications in different fields ranging from biomedical science to drug delivery and paper-making to various electronic devices.

scholarly journals Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 724
Author(s):  
Amilton Iatecola ◽  
Guilherme Arthur Longhitano ◽  
Luiz Henrique Martinez Antunes ◽  
André Luiz Jardini ◽  
Emilio de Castro Miguel ◽  
...  
Keyword(s):  
Surface Modification ◽  
Additive Manufacturing ◽  
Bone Ingrowth ◽  
Orthopedic Implants ◽  
Coated Sample ◽  
High Mechanical Strength ◽  
Coated Surface ◽  
Surface Modification Techniques ◽  
Almost All ◽  
Cobalt Base

Cobalt-base alloys (Co-Cr-Mo) are widely employed in dentistry and orthopedic implants due to their biocompatibility, high mechanical strength and wear resistance. The osseointegration of implants can be improved by surface modification techniques. However, complex geometries obtained by additive manufacturing (AM) limits the efficiency of mechanical-based surface modification techniques. Therefore, plasma immersion ion implantation (PIII) is the best alternative, creating nanotopography even in complex structures. In the present study, we report the osseointegration results in three conditions of the additively manufactured Co-Cr-Mo alloy: (i) as-built, (ii) after PIII, and (iii) coated with titanium (Ti) followed by PIII. The metallic samples were designed with a solid half and a porous half to observe the bone ingrowth in different surfaces. Our results revealed that all conditions presented cortical bone formation. The titanium-coated sample exhibited the best biomechanical results, which was attributed to the higher bone ingrowth percentage with almost all medullary canals filled with neoformed bone and the pores of the implant filled and surrounded by bone ingrowth. It was concluded that the metal alloys produced for AM are biocompatible and stimulate bone neoformation, especially when the Co-28Cr-6Mo alloy with a Ti-coated surface, nanostructured and anodized by PIII is used, whose technology has been shown to increase the osseointegration capacity of this implant.

Comparison of material transfer in electrical discharge machining of AISI H13 die steel

2009 ◽  
Vol 223 (7) ◽  
pp. 1733-1740 ◽  
Author(s):  
S Kumar ◽  
R Singh ◽  
T P Singh ◽  
B L Sethi
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Tungsten Powder ◽  
Material Transfer ◽  
Die Steel ◽  
Cent Increase ◽  
Aisi H13 ◽  
Copper Chromium ◽  
H13 Die Steel ◽  
And Tungsten

The electrical discharge machining (EDM) process is extensively used in the tool and die making industry for accurate machining of internal profiles in hardened materials. Although it is essentially a material removal process, efforts have been made in the recent past to use it as surface treatment method. This article investigates and compares the effect of material transfer from electrode bodies (copper, copper—chromium, and copper—tungsten) and tungsten powder suspended in the dielectric medium during die-sinking EDM of AISI H13 die steel. Results show a 76 per cent increase in micro-hardness by machining with a copper—tungsten electrode and a 111 per cent increase by machining with tungsten powder mixed in the dielectric. The copper—chromium electrode gives the best surface roughness (Ra) value of 2.67 μ m. Scanning electron microscopy and X-ray diffraction analysis of the machined surfaces show alloying of parent material with tungsten and tungsten carbide. Chemical composition of the machined surfaces was further checked on an optical emission spectrometer to verify the results. Besides a significant presence of tungsten, an increase in the percentage of carbon is also observed.

Swirling Fluidized Bed Polishing: A New Non-Conventional Method of Surface Modification

2015 ◽  
Vol 813-814 ◽  
pp. 634-640
Author(s):  
N.K. Francis ◽  
K.G. Viswanadhan ◽  
M.M. Paulose
Keyword(s):  
Surface Modification ◽  
Fluidized Bed ◽  
Metal Removal ◽  
Complex Geometry ◽  
Removal Rate ◽  
Abrasive Particle ◽  
Surface Finishing ◽  
Polished Surface ◽  
Work Piece ◽  
Machining Accuracy

Swirling Fluidized Bed Polishing (SFBP) is a non–traditional alternative abrasive flow surface finishing form of Fluidized Bed Machining (FBM) in which the former has special features to overcome certain significant limitations of the latter, namely the variation of the surface roughness vertically along the component surface and the screening effect owing to the complex contours in the work piece geometry. Owing to its ability to perform machining and generate polished surface from a roughness value of Ra 1.2μ to 0.2 μ within 8 hours of processing, this new method offers greater scope in the surface modification of rough machined surfaces with complex geometry such as component with ducts and grooves. This research focus on investigating the effect of abrasive particle concentration on metal removal rate per unit area of the specimen surface. 3D surface morphology analysis investigates the quality of the polished surface and the study of circumferential uniformity and machining accuracy analysis on a complex-contoured component further investigate its scope and relevance in industrial applications.

scholarly journals Review of titanium surface modification techniques and coatings for antibacterial applications

2019 ◽  
Vol 83 ◽  
pp. 37-54 ◽  
Author(s):  
H. Chouirfa ◽  
H. Bouloussa ◽  
V. Migonney ◽  
C. Falentin-Daudré
Keyword(s):  
Surface Modification ◽  
Titanium Surface ◽  
Surface Modification Techniques

scholarly journals Self-Consolidation and Surface Modification of Mechanical Alloyed Ti-25.0 at.% Al Powder Mixture by Using an Electro-Discharge Technique

2017 ◽  
Vol 62 (2) ◽  
pp. 1293-1297 ◽  
Author(s):  
S.Y. Chang ◽  
H.S. Jang ◽  
Y.H. Yoon ◽  
Y.H. Kim ◽  
J.Y. Kim ◽  
...  
Keyword(s):  
Surface Modification ◽  
Diffusion Process ◽  
Powder Mixture ◽  
Electrical Discharge ◽  
External Pressure ◽  
Solid Core ◽  
Input Energy ◽  
Electrical Discharges ◽  
Al Powder ◽  
Solid Bulk

AbstractElectrical discharges using a capacitance of 450 μF at 0.5, 1.0, and 1.5 kJ input energies were applied in a N2atmosphere to obtain the mechanical alloyed Ti3Al powder without applying any external pressure. A solid bulk of nanostructured Ti3Al was obtained as short as 160 μsec by the Electrical discharge. At the same time, the surface has been modified into the form of Ti and Al nitrides due to the diffusion process of nitrogen to the surface. The input energy was found to be the most important parameter to affect the formation of a solid core and surface chemistry of the compact.

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