scholarly journals Electrochemical Polishing of 7075 Al Alloy in Phosphoric Acid

2021 ◽  
Author(s):  
Han Liu ◽  
Minheng Ye ◽  
Zuoyan Ye ◽  
Lili Wang ◽  
Yuting Hao ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Phosphoric Acid ◽  
Chemical Properties ◽  
Surface Finishing ◽  
Al Alloy ◽  
Electrochemical Polishing ◽  
Electronic Products ◽  
7075 Al Alloy ◽  
Optimized Conditions ◽  
Further Development

Abstract 7075 aluminum (Al) alloy has been widely used in aircraft structures and other high-end electronic products owing to its excellent mechanical and chemical properties, while its damage-free and highly efficient surface finishing remains a challenge. Herein, we demonstrate a systematic study of the anodic behaviors of 7075 Al alloy during the electrochemical polishing (ECP) process in phosphoric acid under different applied potentials, and the changes of surface morphology, roughness, electric current and resistance are studied intensively. According to the surface morphology and current density, ECP of 7075 Al can be divided into 4 stages including the negative leveling stage, leveling and corrosion stage, levelling and brightening stage, and pitting and corrosion stage. Different factors influencing each stage and the effects of impurity phases in the ECP process are experimentally validated. Under optimized conditions, a mirror surface with a roughness (Ra) of 46.7 nm (decreased from an initial value of 153.2 nm) can be obtained by ECP for 10 min. The presented findings are of great value for the further development of ECP process of multiphase alloys.

Etching Treatment Effect on Surface Morphology of Dental Structures

2017 ◽  
Vol 68 (11) ◽  
pp. 2700-2703 ◽  
Author(s):  
Kamel Earar ◽  
Vasile Iulian Antoniac ◽  
Sorana Baciu ◽  
Simion Bran ◽  
Florin Onisor ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Morphology ◽  
Phosphoric Acid ◽  
Human Teeth ◽  
Strong Bond ◽  
Force Microscopy ◽  
Atomic Force ◽  
Human Dentine ◽  
Dental Surface ◽  
Scanning Electron

This study examined and compared surface of human dentine after acidic etching with hydrogen peroxide, phosphoric acid liquid and gel. Surface demineralization of dentin is necessary for a strong bond of adhesive at dental surface. Split human teeth were used. After application of mentioned substances at dentin level measures of the contact angle and surface morphology were employed. Surface morphology was analyzed with the help of scanning electron microscopy and atomic force microscopy. Liquid phosphoric acid yielded highest demineralization showing better hydrophobicity than the rest, thus having more contact surface. Surface roughness are less evident and formed surface micropores of 4 �m remained open after wash and air dry providing better adhesive canalicular penetration and subsequent bond.

scholarly journals Insights on Molecular Characteristics of Hydrochars by 13C-NMR and Off-Line TMAH-GC/MS and Assessment of Their Potential Use as Plant Growth Promoters

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1026 ◽  
Author(s):  
Laís G. Fregolente ◽  
João Vitor dos Santos ◽  
Giovanni Vinci ◽  
Alessandro Piccolo ◽  
Altair B. Moreira ◽  
...  
Keyword(s):  
Plant Growth ◽  
Phosphoric Acid ◽  
13C Nmr ◽  
Chemical Properties ◽  
Water Soluble ◽  
Molecular Characteristics ◽  
Initial Growth ◽  
Growth Promoters ◽  
Molecular Features ◽  
Potential Use

Hydrochar is a carbon-based material that can be used as soil amendment. Since the physical-chemical properties of hydrochar are mainly assigned to process parameters, we aimed at evaluating the organic fraction of different hydrochars through 13C-NMR and off-line TMAH-GC/MS. Four hydrochars produced with sugarcane bagasse, vinasse and sulfuric or phosphoric acids were analyzed to elucidate the main molecular features. Germination and initial growth of maize seedlings were assessed using hydrochar water-soluble fraction to evaluate their potential use as growth promoters. The hydrochars prepared with phosphoric acid showed larger amounts of bioavailable lignin-derived structures. Although no differences were shown about the percentage of maize seeds germination, the hydrochar produced with phosphoric acid promoted a better seedling growth. For this sample, the greatest relative percentage of benzene derivatives and phenolic compounds were associated to hormone-like effects, responsible for stimulating shoot and root elongation. The reactions parameters proved to be determinant for the organic composition of hydrochar, exerting a strict influence on molecular features and plant growth response.

Evolution of mechanical properties in a 7075 Al-alloy subject to natural ageing

2013 ◽  
Vol 49 ◽  
pp. 160-167 ◽  
Author(s):  
Alan G. Leacock ◽  
Conrad Howe ◽  
Desmond Brown ◽  
Odd-Geir Lademo ◽  
Alan Deering
Keyword(s):  
Mechanical Properties ◽  
Al Alloy ◽  
Natural Ageing ◽  
7075 Al Alloy

Effects of the Duration of Potentiostatic Anodizing on the Corrosion Resistance and Surface Morphology of Films Formed on Mg-Al Alloys

2005 ◽  
Vol 486-487 ◽  
pp. 125-128 ◽  
Author(s):  
Seong Jong Kim ◽  
Seok Ki Jang ◽  
Jeong Il Kim
Keyword(s):  
Corrosion Resistance ◽  
Surface Morphology ◽  
Anodic Oxide ◽  
Al Alloys ◽  
Anodic Film ◽  
Al Alloy ◽  
Active Dissolution ◽  
Dissolution Reaction ◽  
Alloy Az91 ◽  
Morphology Of Films

The effects of the duration of potentiostatic anodizing on the corrosion resistance and surface morphology of anodic oxide films formed on Mg-Al alloy (AZ91) in 1 M NaOH were investigated. With the formation of an anodic film, the current density decreased gradually, started to stabilize at 300 s, and was relatively constant at 600 s. These results may be related to the increased time for catalysis of the active dissolution reaction, which not only enlarges the area covered by the anodic film, but also produces a more coherent, thicker film. The reference corrosion potentials of the anodic oxide film for AZ91 shifted in the noble direction with time. In general, the corrosion resistance characteristics were improved with anodizing time.

Surface morphology control on porous anodic alumina in phosphoric acid

2010 ◽  
Vol 518 (14) ◽  
pp. 3797-3800 ◽  
Author(s):  
Rong Zhang ◽  
Kaiming Jiang ◽  
Guqiao Ding
Keyword(s):  
Surface Morphology ◽  
Phosphoric Acid ◽  
Morphology Control ◽  
Anodic Alumina ◽  
Porous Anodic Alumina

scholarly journals Surface morphology changes of acrylic resins during finishing and polishing phases

2013 ◽  
Vol 18 (6) ◽  
pp. 26-30 ◽  
Author(s):  
Glaucio Serra ◽  
Liliane Siqueira de Morais ◽  
Carlos Nelson Elias
Keyword(s):  
Surface Morphology ◽  
Acrylic Resin ◽  
Surface Finishing ◽  
Control Group ◽  
Orthodontic Appliances ◽  
Test Results ◽  
Good Surface ◽  
Acrylic Resins ◽  
Polishing Procedures ◽  
Removable Orthodontic Appliances

INTRODUCTION: The finishing and polishing phases are essential to improve smoothness and shining on the surface of acrylic resins used to make removable orthodontic appliances. A good surface finishing reduces roughness, which facilitates hygiene, prevents staining and provides greater comfort to the patients. OBJECTIVE: The aim of this paper was to analyze the changes on surface morphology of acrylic resins during finishing and polishing phases. METHODS: Thirty discs (10 mm in diameter and 5 mm in length) were made with acrylic resin and randomly divided into ten groups. The control group did not receive any treatment while the other groups received gradual finishing and polishing. The last group received the entire finishing and polishing procedures. Surface morphology was qualitatively analyzed through scanning electron microscopy and quantitatively analyzed through a laser profilometer test. RESULTS: The acrylic resin surfaces without treatment showed bubbles which were not observed in the subsequent phases. Wearing out with multilaminated burs, finishing with wood sandpaper and finishing with water sandpaper resulted in surfaces with decreasing irregularities. The surfaces that were polished with pumice and with low abrasive liquids showed high superficial smoothness. CONCLUSION: Highly smooth acrylic resin surfaces can be obtained after mechanical finishing and polishing performed with multilaminated burs, wood sandpaper, water sandpaper, pumice and low abrasive liquids.

scholarly journals Studying the distribution of hardness values in friction drilled 7075 Al-alloy sheets at different conditions

2021 ◽  
Vol 1172 (1) ◽  
pp. 012026
Author(s):  
N Hamzawy ◽  
M Khedr ◽  
T S Mahmoud ◽  
I Ei-Mahallawi ◽  
T A Khalifa
Keyword(s):  
Al Alloy ◽  
7075 Al Alloy ◽  
Hardness Values

scholarly journals Kinetic Modelling and Optimizing of Butyl Propionate over a Synthesied Material (Tungstan Phosphoric Acid) Heteropoly Catalyst Using Response Surface Technique

2021 ◽  
Vol 45 (4) ◽  
pp. 273-280
Author(s):  
Raju Kalakuntala ◽  
Srinath Surnani
Keyword(s):  
Experimental Data ◽  
Phosphoric Acid ◽  
Response Surface ◽  
Kinetic Modelling ◽  
Quadratic Model ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Response Surface Technique ◽  
Optimized Conditions ◽  
Surface Technique

The performance of heteropoly acid i.e., Tungstan phosphoric acid for the synthesis of butyl propionate at optimized conditions. Effect on conversion and yield of propionic acids using the Response Surface Methodology (RSM) were evaluated by different process parameters including catalyst loading, alcohol/acid molar ratio. There were no external and internal mass transmission limits. A quadratic model acquired by the variance study (ANOVA) has been shown to view experimental data successfully with the regression (R2 = 0.94 and R2 = 0.942) coefficients approaching to unity. The pseudo homogeneous kinetic model (PH) validated with experimental data to determine kinetic parameters i.e., activation energy (45.97 kJ/mol) and frequent factor (91319 L/mol-min).

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