scholarly journals The effect of changing the electrolyte species volume ratio on the electropolishing of aluminum foil

Quimica Hoy ◽  
2012 ◽  
Vol 2 (4) ◽  
pp. 4
Author(s):  
Dena Pourjafari ◽  
Dora Irma Martínez ◽  
Alejandro Vázquez ◽  
Idalia Gómez
Keyword(s):  
Surface Morphology ◽  
Current Density ◽  
Perchloric Acid ◽  
Electrochemical Behavior ◽  
Volume Ratio ◽  
Aluminum Foil ◽  
Aluminum Surface ◽  
Anodization Process ◽  
Pre Treatment

In this paper, the electrochemical behavior and surface morphology of AA1100 were investigated in commercial electropolishing electrolyte consisting of perchloric acid (HCIO4) and ethanol (C2H5OH). Electropolishing of aluminum foil is a pre-treatment on aluminum surface before anodization process. The electropolishing on Al was carried out in different electrolyte concentrations and proper concentrations were reported by using current density-voltage curves, impedance spectroscopies and AFM images.

Optimization on Self-Ordering Process of Electropolishing Surface on High-Purity Aluminum

2014 ◽  
Vol 1053 ◽  
pp. 56-60
Author(s):  
Di Ma ◽  
Shu Bai Li ◽  
Xiu Ying Hu ◽  
Xing Hong Zhao ◽  
Xu Hong Chen
Keyword(s):  
Propylene Glycol ◽  
Current Density ◽  
Perchloric Acid ◽  
High Purity ◽  
Volume Ratio ◽  
Limiting Current ◽  
Mixed Solution ◽  
Salt Film ◽  
Limiting Current Density ◽  
High Purity Aluminum

The electropolishing behavior of high-purity aluminum in perchloric acid ethanol electrolytes is studied by the electrochemical methods. The morphologies of electropolished surface are examined by SEM. The results of anodic polarization shows that the limiting current density was decreased with the 1,2-propylene glycol and perchloric acid volume ratio increasing and the temperature decreasing. The results of SEM show that A salt film with porous pores on the electropolishing surface was formed on high-purity aluminum in the mixed solution of 1, 2 propylene glycol and perchloric acid at the volume ratio of 4:1 and 6:1, porosity of film increases from 12.3 % to18.4%, and the pore diameter of film increases from 19 nm to 23 nm with the current density increased from 120 mAcm-2 to 140 mAcm-2.

scholarly journals Efficiency of integrated electrooxidation and anaerobic digestion of waste activated sludge

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
J. A. Barrios ◽  
A. Cano ◽  
F. F. Rivera ◽  
M. E. Cisneros ◽  
U. Durán
Keyword(s):  
Anaerobic Digestion ◽  
Current Density ◽  
Methane Production ◽  
Energy Recovery ◽  
Energy Analysis ◽  
Mathematical Optimization ◽  
Waste Activated Sludge ◽  
Bdd Electrode ◽  
Vs Removal ◽  
Pre Treatment

Abstract Background Most of the organic content of waste activated sludge (WAS) comprises microbial cells hard to degrade, which must be pre-treated for energy recovery by anaerobic digestion (AD). Electrooxidation pre-treatment (EOP) with boron-doped diamond (BDD) electrode have been considered a promising novel technology that increase hydrolysis rate, by the disintegrating cell walls from WAS. Although electrochemical oxidation could efficiently solubilize organic substances of macromolecules, limited reports are available on EOP of WAS for improving AD. In this endeavour, the mathematical optimization study and the energy analysis of the effects of initial total solids concentrations [TS] of WAS and current density (CD) during EOP on the methane production and removal of chemical oxygen demand (COD) and volatile solids (VS) were investigated. Because limited reports are available on EOP of WAS for improving biogas production, it is not well understood; however, it has started to attract interest of scientists and engineers. Results In the present work, the energy recovery as biogas and WAS conversion were comprehensively affected by CD and [TS], in an integrated EOP and AD system. When working with WAS at 3% of [TS] pre-treated at current density of 24.1 mA/cm2, the highest COD and VS removal were achieved, making it possible to obtain the maximum methane (CH4) production of 305 N-L/kg VS and a positive energy balance of 1.67 kWh/kg VS. Therefore, the current densities used in BDD electrode are adequate to produce the strong oxidant (hydroxyl radical, ·OH) on the electrode surface, allow the oxidation of organic compounds that favours the solubilization of particulate matter and VS from WAS. Conclusions The improvement of VS removal and COD solubilization were due to the effects of pre-treatments, which help to break down the microbial cells for faster subsequent degradation; this allows a decomposition reaction that leads to biodegrade more compounds during AD. The balance was positive, suggesting that even without any optimization the energy used as electricity could be recovered from the increased methane production. It is worth noting that this kind of analysis have not been sufficiently studied so far. It is therefore important to understand how operational parameters can influence the pre-treatment and AD performances. The current study highlights that the mathematical optimization and energy analysis can make the whole process more convenient and feasible.

Study on Electrodeposition of Ni-Graphite Composite Coatings in Sulfamate Bath

2010 ◽  
Vol 150-151 ◽  
pp. 1546-1550 ◽  
Author(s):  
Xiang Zhu He ◽  
Xiao Wei Zhang ◽  
Xin Li Zhou ◽  
Zhi Hong Fu
Keyword(s):  
Surface Morphology ◽  
Process Parameters ◽  
Current Density ◽  
Graphite Particle ◽  
Particle Concentration ◽  
Composite Coatings ◽  
Nickel Matrix ◽  
Graphite Composite ◽  
Surface Morphologies ◽  
Sulfamate Bath

This paper presented the composite coatings of nickel with graphite particle on the aluminum substrate using a nickel sulfamate bath. Effects of graphite particle concentration on the surface morphologies of the composite coatings were investigated. The inclusion of graphite particle into metal deposits was dependent on many process parameters, including particle concentration, current density, pH and temperature. Results of SEM and XRD demonstrated that graphite particle had successfully deposited on that nickel matrix; besides, the surface morphology of coatings obtained from sulfamate bath containing 2g/L graphite particle dispersed more uniformly than the ones with higher concentration.

scholarly journals Influence of Aluminum Surface Morphology on Electroluminescent Intensity.

2000 ◽  
Vol 51 (7) ◽  
pp. 714-717 ◽  
Author(s):  
Tomokazu MAENO ◽  
Go TANIGAWA ◽  
Shigeyoshi MORISAKI
Keyword(s):  
Surface Morphology ◽  
Aluminum Surface

THE EFFECT OF PREPARED PARAMETERS ON THE MICROSTRUCTURE OF ELECTRODEPOSITED NANOCRYSTALLINE NICKEL COATING

2004 ◽  
Vol 11 (04n05) ◽  
pp. 433-442 ◽  
Author(s):  
C. Y. DAI ◽  
Y. PAN ◽  
S. JIANG ◽  
Y. C. ZHOU
Keyword(s):  
Grain Size ◽  
Surface Morphology ◽  
Current Density ◽  
Crystal Orientation ◽  
Nickel Coating ◽  
Pulse Frequency ◽  
Lattice Parameter ◽  
Nanocrystalline Nickel ◽  
Peak Current Density ◽  
Peak Current

The nanocrystalline nickel coating was synthesized by pulse-jet electrodeposition from modified Watts bath. Pulse and jet plating was employed to increase the deposition current density, decrease diffusion layer, increase the nucleation rate and in this case the prepared method would result in fine-grained deposits. Transmission and scanning electron microscopy and X-ray diffraction (XRD) were used to study the microstructure, the surface morphology, the crystal preferred orientation and the variety of the lattice parameter respectively. The influence of pulse parameters, namely peak current density, the duty cycle and pulse frequency on the grain size, surface morphology, crystal orientation and microstructure was studied. The results showed that with increasing peak current density, the deposit grain size was found to decrease markedly in other parameters at constant. However, in our experiment it was found that the grain size increased slightly with increasing pulse frequency. For higher peak current density, the surface morphology was smoother. The crystal orientation progressively changed from an almost random distribution to a strong (111) texture. This means that the peak current density was the dominated parameter to effect the microstructure of electrodeposited nanocrystalline nickel coating. In addition, the lattice parameter for the deposited nickel is calculated from XRD and it is found that the calculated value is less than the lattice parameter for the perfect nickel single crystal. This phenomenon is explained by the crystal lattice mismatch.

Effect of current density on the porous silicon preparation as gas sensors**

2021 ◽  
Vol 30 (1) ◽  
pp. 257-264
Author(s):  
Muna H. Kareem ◽  
Adi M. Abdul Hussein ◽  
Haitham Talib Hussein
Keyword(s):  
Porous Silicon ◽  
Gas Sensors ◽  
Current Density ◽  
Room Temperature ◽  
Low Cost ◽  
High Surface ◽  
Volume Ratio ◽  
Etching Time ◽  
Force Microscopy ◽  
Materials Used

Abstract In this study, porous silicon (PSi) was used to manufacture gas sensors for acetone and ethanol. Samples of PSi were successfully prepared by photoelectrochemical etching and applied as an acetone and ethanol gas sensor at room temperature at various current densities J= 12, 24 and 30 mA/cm2 with an etching time of 10 min and hydrofluoric acid concentration of 40%. Well-ordered n-type PSi (100) was carefully studied for its chemical composition, surface structure and bond configuration of the surface via X-ray diffraction, atomic force microscopy, Fourier transform infrared spectroscopy and photoluminescence tests. Results showed that the best sensitivity of PSi was to acetone gas than to ethanol under the same conditions at an etching current density of 30 mA/cm2, reaching about 2.413 at a concentration of 500 parts per million. The PSi layers served as low-cost and high-quality acetone gas sensors. Thus, PSi can be used to replace expensive materials used in gas sensors that function at low temperatures, including room temperature. The material has an exceptionally high surface-to-volume ratio (increasing surface area) and demonstrates ease of fabrication and compatibility with manufacturing processes of silicon microelectronics.

Crystal Orientation and Surface Morphology of Sono-Electroplated Zinc Film from Alkali Zincate Bath

2009 ◽  
Vol 79-82 ◽  
pp. 1743-1746
Author(s):  
Atsushi Chiba
Keyword(s):  
Surface Morphology ◽  
Current Efficiency ◽  
Compressive Stress ◽  
Diffusion Layer ◽  
Current Density ◽  
Crystal Orientation ◽  
Shearing Stress ◽  
Thickness Of Diffusion Layer ◽  
Zincate Solution

Zn plated on Cu plate from 0.65 mol/dm3 alkali zincate solution in 8 mol/dm3 KOH bath Electrolysis was carried out as current density of 10 - 100 mA/cm2. The sonication was prepared 40 kHz. The current efficiency was 76.1 % at 10 mA/cm2 in 0.10 mol/dm3 zincate and 100 % in 0.15 mol/dm3 zincate at 50 mA/cm2. The current efficiency and thickness of diffusion layer affected with the agitation of micro-jet. Surface of film was smooth and dense as particle crushed down with the shockwave pressure. (112) plane moved horizontally to <113> direction under the compressive stress or shearing stress.

Effect of Current Density on the Composition and Mechanical Properties of Cr1-xAlxN Coating by Ion Arc Plating

2012 ◽  
Vol 557-559 ◽  
pp. 1971-1974
Author(s):  
Cheng Xi Wang ◽  
Ji Hua Peng ◽  
Xian Wen Liang ◽  
Jun Tian
Keyword(s):  
Mechanical Properties ◽  
Surface Morphology ◽  
Current Density ◽  
Adhesion Force ◽  
Atomic Ratio ◽  
Pure Metal ◽  
Metal Target ◽  
Micro Hardness ◽  
Al Content ◽  
Maximum Value

The Cr1-xAlxN coatings were deposited onto M2 tool steel using ion arc plating technique. The effect of current density on the surface morphology and mechanical properties of TiN/CrAlN coating was made. It was found that adjusting the pure metal target currents is not only to change the metal atomic ratio, but also to influence the surface morphology, their hardness and adhesion. The micro hardness Hv increases almost linearly with Al content of the coating in this study, and the Cr0.41Al0.59N coating reaches Hv 2950. The adhesion force between the coating and the substrate reaches maximum value 55N, when the [Al]/[Al+Cr] ratio is 0.44.

Determination of Organochlorine Pesticides in Saussurea Costus by Ultrasonic Extraction and Solid-Phase Microextraction Method

2012 ◽  
Vol 554-556 ◽  
pp. 1947-1951
Author(s):  
Wei Liu ◽  
Du Shu Huang ◽  
Na Wu ◽  
Ju Cheng Zhang ◽  
Ping Yi ◽  
...  
Keyword(s):  
Petroleum Ether ◽  
Organochlorine Pesticides ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Volume Ratio ◽  
Ultrasonic Extraction ◽  
Extraction And Purification ◽  
Ultrasonic Time ◽  
Pre Treatment

Ultrasonic extraction and purification using solid-phase microextraction column for the determination of 7 types of organochlorine pesticides including α, β, γ, δ-BHC, 2,4 '-DDT, 4,4'-DDT and heptachlor from the Saussrrea cotus were investigated in this study. The pretreatment of Saussrrea cotus samples, the effect of different ultrasonic time on the extraction efficiency and the effect of different ratio of dichloromethane: petroleum ether on purification efficiency were studied. Results show that the satisfactory extraction conditions for pre-treatment process are: 30 minutes ultrasonic treatment; the volume ratio of dichloromethane and petroleum ether mixture is 3:7.

Improvement of microstructure and properties of Ni–Al2O3 composite coating via jet electrodeposition

2020 ◽  
Vol 34 (27) ◽  
pp. 2050243
Author(s):  
Hui Fan ◽  
Jie Jiang ◽  
Yangpei Zhao ◽  
Shankui Wang ◽  
Zhijing Li
Keyword(s):  
Wear Rate ◽  
Surface Morphology ◽  
Composite Coating ◽  
Process Parameters ◽  
Current Density ◽  
Composite Coatings ◽  
Coating Structure ◽  
Mechanical And Tribological Properties ◽  
Al2o3 Composite ◽  
Jet Electrodeposition

Ni–Al2O3 composite coatings were prepared with a modified Watt’s bath by using jet electrodeposition method. As the key process parameter, current density and the addition of Al2O3 nanoparticles in electrolyte were studied about the effect on the surface morphology and co-deposition of Al2O3 nanoparticles of composite coating. The mechanical and tribological properties of the composite coating were also tested. The results show that properly increasing the current density and Al2O3 addition can increase the co-deposition of nanoparticles in the coating and promote the formation of a dense and refined coating structure. Using the optimized process parameters of current density (300 A/dm2) and Al2O3 addition (30 g/L), the co-deposition of Al2O3 in the composite coating can reach a maximum of 13.1 at.%. The hardness of the coating reaches the peak at 623 HV. The wear rate of the composite coating is also greatly reduced with optimized parameters.

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