scholarly journals Microstructural characterization and film-forming mechanism of a phosphate chemical conversion ceramic coating prepared on the surface of 2A12 aluminum alloy

RSC Advances ◽  
2019 ◽  
Vol 9 (33) ◽  
pp. 18767-18775
Author(s):  
Shuai Huang ◽  
Jian Wang ◽  
Xiaowei Wei ◽  
Yuli Zhou ◽  
Lijun Wang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Ceramic Coating ◽  
Microstructural Characterization ◽  
Chemical Conversion ◽  
Ceramic Coatings ◽  
Conversion Process ◽  
Forming Mechanism ◽  
Alloy Substrate ◽  
Film Forming

Phosphate chemical conversion (PCC) ceramic coatings on the surface of 2A12 aluminum alloy substrate have been fabricated by a simple and inexpensive chemical conversion process in CrO3–NaF–H3PO4 solution.

Influence of KF Concentration on Thickness and Energy Consumption of Micro-Arc Oxidation Coatings on LY12 Aluminum Alloy Substrate

2012 ◽  
Vol 430-432 ◽  
pp. 462-465
Author(s):  
Jing Chen ◽  
Jin Yong Xu ◽  
Jia Chen Zhao ◽  
Cheng Gao ◽  
Gui Wang
Keyword(s):  
Aluminum Alloy ◽  
Energy Consumption ◽  
Sodium Silicate ◽  
Phase Structure ◽  
Average Energy ◽  
Ceramic Coatings ◽  
Electrolytic Solution ◽  
Alloy Substrate ◽  
Micro Arc Oxidation

In this paper, ceramic coatings were produced on LY12 aluminum alloy by the micro-arc oxidation (MAO) technique in an alkali sodium silicate electrolyte consisting of different KF concentrations(0~15g/l). The influence of KF concentration on making energy consumption and thickness of the MAO coatings was studied. Results revealed that increasing KF concentration caused an increase in the thickness and roughness of coatings and a decrease in the average energy during the MAO process. In response to the increase in KF concentration, the little content of F- in the coatings were increased simultaneously. However, the phase structure and composition of the coatings hardly varied with different KF concentrations. Moreover, it was observed that the coatings produced in electrolytic solution with 10g/L concentration of KF obtained an excellent thickness and making energy, but the coatings were ablated locally with the KF concentration of higher than 10g/L for more than 60 minutes.

The Effects of Graphite on Ceramic Coatings on LY12 Aluminium Alloys by Micro-Arc Oxidation

2012 ◽  
Vol 454 ◽  
pp. 126-129 ◽  
Author(s):  
Jing Long Gao ◽  
Zhong Cai Shao
Keyword(s):  
Aluminum Alloy ◽  
Friction Coefficient ◽  
Aluminum Alloys ◽  
Aluminium Alloys ◽  
Ceramic Coating ◽  
Graphite Powder ◽  
Sodium Metasilicate ◽  
Ceramic Coatings ◽  
Graphite Phase ◽  
Micro Arc Oxidation

LY12 aluminum alloy samples were treated by micro-arc oxidation in sodium metasilicate electrolytes with graphite powder. The effects of graphite concentration on thickness, roughness, friction coefficient and phase composite of ceramic coating were investigated. The results indicated that the roughness and friction coefficient of ceramic coatings increased linearly. However, the thickness decreased adding graphite powder. XRD analyses indicated that the ceramic coatings fabricated on the surface of aluminum alloys by micro-arc oxidization were composed of graphite phase. SEM showed that the porosity of the ceramic coatings with distributing nonuniform micropore diameter were inceased with the increasing graphite concentration.

Synthesis and Characterization of Aluminum Nitride Ceramic Coating on Aluminum Alloy by Plasma Electrolytic Oxidation in CO(NH2)2 Electrolyte

2012 ◽  
Vol 557-559 ◽  
pp. 1664-1667 ◽  
Author(s):  
Yun Long Wang ◽  
Miao Wang ◽  
Zhao Hua Jiang
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Aluminum Nitride ◽  
Bonding Strength ◽  
Plasma Electrolytic Oxidation ◽  
Ceramic Coating ◽  
Average Diameter ◽  
Ceramic Coatings ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

aluminum nitride ceramic coating were obtained on LY12 aluminum alloy by plasma electrolytic oxidation in CO(NH2)2 electrolyte. The microstructure of the ceramic coating including phase and elements composition, surface and cross section morphology were investigated. The properties of the ceramic coatings such as surface roughness, thickness and bonding strength were primarily studied. The results show that the ceramic coating on LY12 aluminum alloy surface was AlN coating with the thickness of 12 um. The AlN ceramic coating showed rough and porous. The average diameter of the pores was 6 um and the surface roughness was 1.5 um. The bonding strength of the coating was 18 ± 2 MPa.

Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

1989 ◽  
Vol 47 ◽  
pp. 426-427
Author(s):  
Ozer Unal
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Ceramic Coating ◽  
High Vacuum ◽  
Ceramic Coatings ◽  
High Energy ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

scholarly journals Physicochemical and Microstructural Characterization of Whey Protein Films Formed with Oxidized Ferulic/Tannic Acids

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1599
Author(s):  
Yaosong Wang ◽  
Youling L. Xiong
Keyword(s):  
Whey Protein ◽  
Microstructural Characterization ◽  
Protein Isolate ◽  
Light Transmittance ◽  
In Vitro Digestibility ◽  
Protein Films ◽  
Film Forming ◽  
Protein Sulfhydryl ◽  
Reduced Light

Protein-based biodegradable packaging films are of environmental significance. The effect of oxidized ferulic acid (OFA)/tannic acid (OTA) on the crosslinking and film-forming properties of whey protein isolate (WPI) was investigated. Both of the oxidized acids induced protein oxidation and promoted WPI crosslinking through the actions of quinone carbonyl and protein sulfhydryl, and amino groups. OTA enhanced the tensile strength (from 4.5 MPa to max 6.7 MPa) and stiffness (from 215 MPa to max 376 MPa) of the WPI film, whereas OFA significantly increased the elongation at break. The water absorption capability and heat resistance of the films were greatly improved by the addition of OTA. Due to the original color of OTA, the incorporation of OTA significantly reduced light transmittance of the WPI film (λ 200–600 nm) as well as the transparency, whereas no significant changes were induced by the OFA treatment. Higher concentrations of OTA reduced the in vitro digestibility of the WPI film, while the addition of OFA had no significant effect. Overall, these two oxidized polyphenols promoted the crosslinking of WPI and modified the film properties, with OTA showing an overall stronger efficacy than OFA due to more functional groups available.

A study of the adhesion of thiokol-epoxy hermetics to a brass and an aluminum alloy substrate

1991 ◽  
Vol 5 (9) ◽  
pp. 691-695 ◽  
Author(s):  
E.S. NEFED'EV ◽  
T. Yu. Mirakova ◽  
L.A. Averko-Antonovich ◽  
M.K. Kadirov ◽  
A.V. IL'YASOV
Keyword(s):  
Aluminum Alloy ◽  
Alloy Substrate

Variable Parameter Processes of Micro-Arc Oxidation for Aluminium Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 1273-1278
Author(s):  
Cheng Gao ◽  
Jin Yong Xu ◽  
Xuan Yi Shi ◽  
Ya Juan Liu ◽  
Jing Chun Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Wear Rate ◽  
Ceramic Coating ◽  
Early Stage ◽  
Variable Parameter ◽  
Ceramic Coatings ◽  
Constant Current ◽  
Constant Voltage ◽  
Micro Arc Oxidation ◽  
The Way

In micro-arc oxidation process, ceramic coating had a rapid growth all along by the way of constant current oxidation, and ceramic coating had a low roughness by the way of constant voltage oxidation. But few research focus on the mixed control process of constant current oxidation and constant voltage oxidation. In this paper we propose a variable parameter process that can combine the advantages of constant current and constant voltage oxidation for the first time. The growth kinetics of different technics was analyzed according to the change law of current and voltage. Surface topographs of ceramic coating were observed using scanning electron microscopy (SEM). The friction tests were carried out using a self-made friction tester. The results show that ceramic coating has an upper growth rate and a low roughness by the process of constant current+constant voltage oxidation. The ceramic coating has a high growth rate by process of constant voltage+constant current oxidation. The results of friction test indicate that the wear rate and roughness of ceramic coating are positive correlation at early stage of friction. While the ceramic coatings treated by different technics have the close wear rate at stable friction stage, which embodies the inner layer of ceramic coating has a well antiwear behavior.

Sign in / Sign up

Export Citation Format

Share Document