Papers by Keyword: Anodic Dissolution

Abstract: Non-conventional machine are nowadays plays a vital role in manufacturing complex shaped products and to produce the product with high accuracy the electrochemical machining is widely used to machine complicated shapes for electrically conducting difficult-to-machine materials such as super alloys, Ti-alloys, alloy steel, tool steel, stainless steel, etc. such titanium-based alloys are in common use for aero engine components such as blades and blisks (blade integrated disks). Therefore, in this present work to investigate the influence of some predominant electrochemical process parameters such as applied voltage, electrolyte concentration, Micro-tool feed rate and duty cycle on the metal removal rate , overcut and surface roughness to fulfill the effective utilization of electrochemical machining of Pure-titanium. The purpose of this study is to investigate the influence of process parameters on machining characteristics and optimize the combination of those parameters using Taguchi-grey relational analysis. From this result, it is observed that process parameters have significant role in Electrochemical Micromachining process and the optimization values has been found using proposed multi-response methodology.

Abstract: The corrosion behaviour of AM60 magnesium alloy containing 1.88 wt.% Cd in 0.1 M NaCl solution was investigated by weight loss and hydrogen evolution measurements. The microstructure was evaluated using EPMA. Cd was observed to have an even distribution, hence, no new phase was formed. The corrosion resistance was enhanced by the addition of Cd. The rate of corrosion reduced by a factor of 1.5 times that of AM60 alloy. The microstructure played a crucial role as the presence of defects in the alloys initiated and accelerated corrosion.

Abstract: The behavior of chrome alloyed steel in various combinations of inorganic media has been studied. Steel samples were processed by electrochemical discharge grinding in nitrates (KNO₃, NaNO₃), chlorate solution (NaClO₃) and nitrates with various additives (KNO₃+Na₂CO₃, NaNO₃ +NaClO₃). In inorganic solutions, the presence of a great number of negative ions (NO₃^-, ClO₃^- HO^-) resulted by electrolytic dissociation of the salts, increases the metal oxidation as well as anodic dissolution. The rate of metal dissolution increased with the increasing NO₃^- ions that accelerate the anodic dissolution

Abstract: Acoustic emission signals were continuously monitored during corrosion fatigue crack propagation for X52 steel in 3.5% NaCl and AZ31 magnesium alloy in 0.1%NaCl solution. There are different microstructure and corrosion fatigue crack propagation mechanism for X52 steel and AZ31B magnesium alloy. Combined with the existing research results of LY12CZ and 7075-T6 aluminum alloys, the acoustic emission waveform parameter, the frequency centroid ratio, was tried to use as a criterion to distinguish the corrosion fatigue crack propagation mechanism for anodic dissolution and hydrogen embrittlement. The results also show that the nature of the acoustic emission source determines the main characteristics of the signal parameters and waveforms, and little to do with the experimental material.

Abstract: This paper analyzed the HSLA pipeline steel’s stress corrosion behavior and mechanism which tested in the saturated solution of H2S. The steel’s SSCC susceptibility was determined by constant load tensile according to NACE TM-0177 standard. Used SEM observed the fracture, and then the steel’s corrosion rate and short-term corrosion behavior were analyzed by electrochemical polarization curves in saturated solution of H2S in the environment A. The results show that the steel has a large SSCC susceptibility and a high corrosion rate. What’s more, corrosion rate increases with the increase of immersion time. The results also show that the crack fracture of the steel is caused by anodic dissolution and the hydrogen which penetrates into the steel can increase the anodic dissolution.

Abstract: Anodic dissolution on p-type silicon thin film in hydrofluoric acid solutions leads to a reduction of roughness on these surfaces. The electrochemical behavior in different HF concentration is investigated by linear sweep scan, and it is found that the HF has an important role in electrochemical behaviors, and the anodic dissolution rate increases with increasing HF concentration. A smooth surface state can be obtained in HF solutions, and the technique is promising for fabrication of reflecting silicon surfaces.

Abstract: Electrochemical machining (ECM) is the controlled removal of material by anodic dissolution in an electrolytic cell in which the workpiece is the anode and the tool is the cathode. The ECM presents the advantages: three-dimensional surfaces with complicated profiles can be easily machined in a single operation, irrespective of the hardness and strength of the material. ECM offers a higher rate of metal removal as compared to traditional and nontraditional methods, especially when high machining currents are employed. There is no wear of the tool, which permits repeatable production. This work shows a study of development of a prototype of electrochemical machining (ECM) developed at the Federal University of Uberlândia Minas Gerais-Brazil. A state-of-the-art ECM system is the art of assemblage of facilities including a proper ECM machine, a power supply, a process parameter control system, and an electrolyte preparation, feed and purification system. With the prototype developed, the material removal rate (MRR) was studied. The MRR was influenced by tool feed rate and type of electrolyte.