(Invited) Localized Breakdown of the Natural Oxide Film on Aluminum by Chloride Ions and the Formation of Oxide Blisters

2019 ◽  
Vol 33 (16) ◽  
pp. 47-56
Author(s):  
Edward McCafferty ◽  
Paul M. Natishan
Keyword(s):  
Oxide Film ◽  
Chloride Ions ◽  
Natural Oxide ◽  
Natural Oxide Film

Effect of natural oxide film on the deuterium permeation behavior of 430 stainless steel

2020 ◽  
Vol 152 ◽  
pp. 111469
Author(s):  
Hongtao Huang ◽  
Jianpin Zheng ◽  
Shuo Ding ◽  
Weijun Wang ◽  
Huafeng Zhang
Keyword(s):  
Stainless Steel ◽  
Oxide Film ◽  
430 Stainless Steel ◽  
Natural Oxide ◽  
Natural Oxide Film

The protective properties of the natural oxide film on aluminium

Vacuum ◽  
1952 ◽  
Vol 2 (4) ◽  
pp. 413-414
Keyword(s):  
Oxide Film ◽  
Protective Properties ◽  
Natural Oxide ◽  
Natural Oxide Film

Ellipsometric studies of the natural oxide film on the surface of cadmium telluride

2013 ◽  
Vol 80 (8) ◽  
pp. 515 ◽  
Author(s):  
V. A. Odarich ◽  
A. Z. Evmenova ◽  
F. F. Sizov
Keyword(s):  
Oxide Film ◽  
Cadmium Telluride ◽  
Natural Oxide ◽  
Natural Oxide Film

scholarly journals Effect of Fe, Ni, and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy under different pH conditions

2018 ◽  
Vol 8 (3) ◽  
pp. 241-253
Author(s):  
Mohammad Salim Kaiser ◽  
Maglub Al Nur
Keyword(s):  
Corrosion Rate ◽  
Oxide Film ◽  
Corrosion Behaviour ◽  
Chloride Ions ◽  
Surface Oxide ◽  
Surface Oxide Film ◽  
Sem Images ◽  
Optical Micrograph ◽  
Ph Conditions ◽  
Ph Range

Effect of Fe, Ni and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy was studied. The test of corrosion behaviour at different environmental pH 1, 3, 5, 7, 9, 11 and 13 was performed using conventional gravimetric measurements and complemented by resistivity, optical micrograph, scanning electron microscopy (SEM) and X-ray analyser (EDX) investigations. The highest corrosion rate was observed at pH 13 followed by pH 1, while in the pH range of 3.0 to 11, there is a high protection of surface due to formation of stable surface oxide film. The highest corrosion rate at pH 13 is due to presence of sodium hydroxide in the solution in which the surface oxide film is soluble. At pH 1, however, high corrosion rate can be attributed to dissolution of Al due to the surface attack by aggressive chloride ions. Presence of Fe, Ni and Cr in hyper-eutectic Al-Si automotive alloy has significant effect on the corrosion rate at both environmental pH values. Resistivity of alloy surfaces initially decreases at pH 1 and pH 13 due to formation of thin films. The SEM images of corroded samples immersed in pH 1 solution clearly show pores due to uniform degradation of the alloy. In pH 13 solution, however, the corrosion layer looks more packed and impermeable.

scholarly journals Binary Additives Enhance Micro Arc Oxidation Coating on 6061Al Alloy with Improved Anti-Corrosion Property

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 128 ◽  
Author(s):  
Qingjun Zhu ◽  
Binbin Zhang ◽  
Xia Zhao ◽  
Binbin Wang
Keyword(s):  
Aluminum Alloys ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Corrosion Property ◽  
Economic Method ◽  
Micro Cracks ◽  
Natural Oxide ◽  
Micro Arc Oxidation ◽  
Thickness Meter ◽  
Natural Oxide Film

Given the corrosion tendency of the natural oxide film of aluminum alloys, micro arc oxidation (MAO) treatment is used as an efficient and economic method to enhance the corrosion resistance. However, irregular voids, pores, and micro cracks are easily formed during the MAO process, which are harmful to the anti-corrosion property of MAO coatings. In this paper, binary additives of electrolytes, including (NaPO3)6 and H3BO3, were used to obtain MAO coatings with improved thickness and compact microstructures on 6061 aluminum alloys. The as-prepared coatings were investigated using a thickness meter, scanning electron microscope (SEM), X-ray diffractometer (XRD), and electrochemical impedance spectroscope (EIS). The results showed that the coordinated influence of the binary additives could change the discharge behaviors and micro morphologies of the MAO coatings compared to the base silicate electrolyte. A thicker and stronger MAO coating could be achieved, which was mainly composed of Al2O3 phases. The EIS tests revealed that the corrosion current density of the obtained optimal MAO coating decreased by three orders of magnitude from 1.209 × 10−6 A·cm−2 to 2.981 × 10−9 A·cm−2. We believe that the binary additive-enhanced MAO coatings could provide a promising anti-corrosion solution in various applications.

scholarly journals Anodizing under conditions of oxygen activation of the inter-electrode gap

2021 ◽  
Vol 346 ◽  
pp. 02023
Author(s):  
Nikolay Kolenchin ◽  
Denis Denisenko
Keyword(s):  
High Speed ◽  
Environmental Parameters ◽  
Electrolytic Cell ◽  
Electrode Gap ◽  
Structure Thickness ◽  
Interelectrode Gap ◽  
Wide Range ◽  
Natural Oxide ◽  
Composition Structure ◽  
Natural Oxide Film

Structured alumina is currently used in a wide range of applications. Interest in a surface with a wear-resistant coating motivates creation of methods for high-speed oxidation with an increase in the thickness and hardness of the layer, with obligatory observance of environmental parameters and a decrease in the energy intensity of production. Considering the activity of aluminum towards oxygen, a very important aspect is the search for conditions to increase the natural oxide film to the level of functional significance. The generally accepted scheme of classical anodizing represents a closed system of an electrolytic cell, inside which the elements are activated in the interelectrode gap to the state of ionic excitation under the action of an electric field. The efficiency of interaction depends on the medium’s nature and variability of the volt-ampere parameters. This work proposes a different mechanism for intensifying the process. Oxygen is activated outside the electrolytic cell and in the allotropic state, in the form of ozone, is transmitted into the interelectrode gap. The phase composition, structure, thickness, and microhardness are investigated. The aim of the research is to establish the effect of ozone on the oxidation process.

Junction of the Epithelium and Lamina Propria of the Bovine Rumen Mucosa

1967 ◽  
Vol 25 ◽  
pp. 68-69
Author(s):  
Al W. Stinson
Keyword(s):  
Osmium Tetroxide ◽  
Squamous Epithelium ◽  
Short Chain Fatty Acids ◽  
Chloride Ions ◽  
Fermentation Products ◽  
Ruminant Species ◽  
Protective Shield ◽  
Stratified Squamous Epithelium ◽  
Lead Hydroxide ◽  
Acetic Acids

The stratified squamous epithelium which lines the ruminal compartment of the bovine stomach performs at least three important functions. (1) The upper keratinized layer forms a protective shield against the rough, fibrous, constantly moving ingesta. (2) It is an organ of absorption since a number of substances are absorbed directly through the epithelium. These include short chain fatty acids, potassium, sodium and chloride ions, water, and many others. (3) The cells of the deeper layers metabolize butyric acid and to a lesser extent propionic and acetic acids which are the fermentation products of rumen digestion. Because of the functional characteristics, this epithelium is important in the digestive process of ruminant species which convert large quantities of rough, fibrous feed into energy.Tissue used in this study was obtained by biopsy through a rumen fistula from clinically healthy, yearling holstein steers. The animals had been fed a typical diet of hay and grain and the ruminal papillae were fully developed. The tissue was immediately immersed in 1% osmium tetroxide buffered to a pH of 7.4 and fixed for 2 hrs. The tissue blocks were embedded in Vestapol-W, sectioned with a Porter-Blum microtome with glass knives and stained with lead hydroxide. The sections were studied with an RCA EMU 3F electron microscope.

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