anodic oxidation
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Author(s):  
XIAOZHE YANG ◽  
Xu Yang ◽  
Haiyang Gu ◽  
Kentaro Kawai ◽  
Kenta Arima ◽  
...  

Abstract Slurryless electrochemical mechanical polishing (ECMP) is very effective in the polishing of silicon carbide (SiC) wafers. To achieve a high material removal rate (MRR) of SiC wafer using ECMP with low electrical energy loss, charge utilization efficiency in the anodic oxidation of the SiC surface was investigated and the underlying mechanism was clarified by modeling the anodic oxidation system of SiC in 1 wt% NaCl aqueous solution. The charge utilization efficiency in the anodic oxidation of SiC was found to be constant when the current density was less than 20 mA/cm2 and significantly decreased when the current density was greater than 30 mA/cm2, resulting in a significant reduction in the MRR. Modeling of the anodic oxidation system indicates that the charge utilization efficiency depended on the potential applied on the SiC surface: the oxidation of SiC occupied the dominant position in the anodizing system when the potential is lower than 25 V vs Ag|AgCl, charge utilization efficiency greatly decreased when the applied potential was greater than 25 V owing to the occurrence of oxidations of the H2O and Cl-. This research provides both a theoretical and practical foundation for using ECMP to polish SiC wafers.


Water ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 95
Author(s):  
Yeney Lauzurique ◽  
Lidia Carolina Espinoza ◽  
César Huiliñir ◽  
Verónica García ◽  
Ricardo Salazar

Winery wastewater represents the largest waste stream in the wine industry. This deals with the mineralization of the organic matter present in winery wastewater using anodic oxidation and two types of anodes—namely, a boron-doped diamond electrode (BDD) and two mixed metal oxides (MMO), one with the nominal composition Ti/Ru0.3Ti0.7O2 and the other with Ti/Ir0.45Ta0.55O2. To conduct the study, the variability of different quality parameters for winery wastewater from the Chilean industry was measured during eight months. A composite sample was treated using anodic oxidation without the addition of supporting electrolyte, and the experiments were conducted at the natural pH of the industrial wastewater. The results show that this effluent has a high content of organic matter (up to 3025 ± 19 mg/L of total organic carbon (TOC)), which depends on the time of the year and the level of wine production. With MMO electrodes, TOC decreased by 2.52% on average after 540 min, which may be attributed to the presence of intermediate species that could not be mineralized. However, when using a BDD electrode, 85% mineralization was achieved due to the higher generation of hydroxyl radicals. The electrolyzed sample contained oxamic, acetic, and propionic acid as well as different ions such as sulfate, chloride, nitrate, and phosphate. These ions can contribute to the formation of different species such as active species of chlorine, persulfate, and perphosphate, which can improve the oxidative power of the system.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sara Zandi ◽  
Farzad Nikpour

Abstract Electrochemical bromination and iodination of some pyrazoles were investigated under constant-current (CC) electrolysis in an undivided electrochemical cell. Anodic oxidation of KX salt produces X2 in-situ which can be consumed as an expedient electrophile in pyrazoles aromatic electrophilic substitution reactions or may participate in an X–N coupling reaction with electrochemically catalyzed pyrazolesox to form the halogenated pyrazoles. All reactions proceeded without the need to use any hazardous reagents or catalysts. The reaction conditions are mild and environmentally compatible.


Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1498
Author(s):  
Chaojie Jing ◽  
Ruijue Wang ◽  
Fangchao Zhao ◽  
Lunwu Zhang ◽  
Qiongyao He ◽  
...  

On aluminum alloys of grades 1060, 2024 and 7075, regular and highly uniform oxide films were formed by anodic oxidation. Anodizing was carried out at a constant pressure in a phosphoric acid solution of various concentrations. Using scanning electron microscopy (SEM) and X-ray diffraction (XRD), the optimal characteristics of the method of anodic oxidation for forming uniform oxide films on aluminum alloys were determined: anodic oxidation time, temperature, voltage and the concentration of H3PO4. It was found that, in the process of anodizing, the films have gone through four stages: a non-porosity stage, a mixed stage, an ordered porosity stage and a disordered porosity stage.


Author(s):  
Charlotte Ovenden ◽  
Ian Farrer ◽  
Maurice S Skolnick ◽  
Jon Heffernan

Abstract Scanning probe microscopy assisted local anodic oxidation offers advantages over other semiconductor fabrication techniques as it is a low contamination method. We demonstrate the fabrication of deep and highly reproducible nanohole arrays on InP using local anodic oxidation. Nanohole and nano-oxide mound radius and depth are controlled independently by altering atomic force microscope tip bias and humidity, with a maximum nanohole depth of 15.6 ± 1.2 nm being achieved. Additionally, the effect of tip write speed on oxide line formation is compared for n-type, p-type and semi-insulating substrates, which shows that n-type InP oxidises at a slower rate that semi-insulated or p-type InP. Finally, we calculate the activation energy for LAO of semi-insulating InP to be 0.4 eV, suggesting the oxidation mechanism is similar to that which occurs during plasma oxidation.


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