THE EFFECT OF TITANIA SOL IN PHOSPHATE ELECTROLYTE ON MICROARC OXIDATION COATINGS ON ALUMINUM ALLOY

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3190-3195 ◽  
Author(s):  
MING QI TANG ◽  
WEI PING LI ◽  
HUI CONG LIU ◽  
LI QUN ZHU
Keyword(s):  
Aluminum Alloy ◽  
Growth Process ◽  
Energy Dispersive Spectrometry ◽  
Microarc Oxidation ◽  
X Ray ◽  
Black Coating ◽  
Titania Sol ◽  
Thickness Meter ◽  
Scanning Electron ◽  
Phosphate Electrolyte

Black and gray microarc oxidation coatings have been obtained on 2A70 Aluminum alloy in phosphate electrolyte with and without titania sol, respectively. The growth process of the microarc oxidation coating in the electrolyte with titania sol was investigated. The coating was characterized by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray. The coating thickness was measured by eddy current thickness meter. The results show that the titania sol increase the growth rate of microarc oxidation coating. In both cases the composition of coatings contain Al and O , and are mainly composed of γ- Al 2 O 3 and AlPO 4. Compared with the gray coating, large amount of Ti is found on the surface of black coating. The titania sol added in the electrolyte results in Ti in the coating, in the form of TiO and Al 2 TiO 5.

Corrosion Resistance of Al2O3-ZrO2 Composite Coating by Microarc Oxidation on 2A12 Aluminum Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 672-675
Author(s):  
Yu Hai Li ◽  
Yan Zhao ◽  
Bao Yi Li
Keyword(s):  
Aluminum Alloy ◽  
Composite Coating ◽  
Composite Coatings ◽  
Microarc Oxidation ◽  
Composite Ceramic ◽  
Ceramic Coatings ◽  
X Ray Diffraction ◽  
Mixed Electrolyte ◽  
X Ray ◽  
Thickness Meter

The Al2O3-ZrO2 composite ceramic coatings were prepared on 2A12 aluminum alloy by Microarc oxidation in the mixed electrolyte of 40g/L Na2SiO3 and 8g/L Na2WO4 solution containing different ZrO2 content particles. The thickness of the coatings was measured by an eddy current thickness meter. Microstructure and phase composition were analyzed by scanning election microscopy (SEM) and X-Ray diffraction (XRD), respectively. The experimental results show that ZrO2 in electrolyte can promote coatings growth; Al2O3-ZrO2 composite ceramic coatings consist of α-Al2O3, t-ZrO2, m-ZrO2, and ZrO2 is located in island-like discharge channels and does not destroy the integrity of composite coatings; There is scarcely any erosion on the surface of Al2O3-ZrO2 composite coatings because the intermediate product Zr(OH)4 could suppress composite coating corrosion.

Study and Properties of a Steel Microalloyed Hardened Superficially

2015 ◽  
Vol 365 ◽  
pp. 122-127 ◽  
Author(s):  
N. López-Perrusquia ◽  
M.A. Doñu Ruiz ◽  
C. R. Torres San-Miguel ◽  
M. Flores-Báez ◽  
I. Flores-Báez
Keyword(s):  
Growth Process ◽  
Energy Dispersive Spectrometry ◽  
Boride Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Controlled ◽  
Boriding Process ◽  
Kinetics Of ◽  
Over Time ◽  
Scanning Electron

In this study, we present a boronizing treatment on a steel microalloy that was performed according to dehydrated paste-pack boriding. The temperatures conducted were at 1173, 1223 and 1273 K; at various exposure times of 1, 3, 6 and 9 h. As a result of the boriding process, diffusion-controlled growth of the FeB/Fe2B layers was obtained at the surface of the micro-alloy steel, and the kinetics of the growth process changed parabolically over time. The results of these examination properties of the boride layer as revealed by Optical Microscopy (OP) showed the morphology of the boride layer as a saw-tooth with a thickness ranging from 33 μm to 220 μm depending on the boronizing time. The analysis of Scanning Electron Microscopy (SEM-EDS); showed a distribution of the alloying elements that were detected by Energy Dispersive Spectrometry. The X-ray diffraction (XRD) technique indicated that the surface was a mixture of FeB and Fe2B borides. The evaluation of adhesion of the layers was determined by the technique of Rockwell-C hardness. Young’s modulus and hardness of the layer were evaluated by a nanoindentation technique with a load of 250 mN. The paste dehydrate boriding of micro-alloy reveal a change of properties on the surface; also the coatings FeB and Fe2B, to make a sacrificial function in the steels micro alloyed as widely used in pipelines transporting oil.

Microstructure and Tribological Properties of Microarc Oxidation Coatings on Al-Si Alloy

2016 ◽  
Vol 703 ◽  
pp. 112-118
Author(s):  
Chuang Lu ◽  
Fa Qin Xie ◽  
Li Ping Zhu
Keyword(s):  
Wear Resistance ◽  
Electron Microscope ◽  
Growth Process ◽  
Energy Dispersive Spectrometer ◽  
Microarc Oxidation ◽  
X Ray Diffraction ◽  
Wear Properties ◽  
X Ray ◽  
Microstructure Characteristics ◽  
Scanning Electron

Microarc oxidation(MAO) was used to prepare the coatings on the surface of Al-Si alloy. Besides, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) were utilized to research the microstructure characteristics, the components distribution, and the phase compositions, for the microarc oxidation coatings on Al-Si alloys. Furthermore, the growth process and wear properties of the coatings were explored. Results indicated that:the phase compositions of microarc oxidized coating consisted of mullite (3Al2O3·2SiO2), α- Al2O3 and γ- Al2O3. With the increase of load, the friction coefficient of the coating decreased, however it was greater than that of Al-Si alloy substrate. The wear resistance of the coating were one time higher than that of the substrate.

scholarly journals Analytical study of Buddha sculptures in Jingyin temple of Taiyuan, China

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaojian Bai ◽  
Chen Jia ◽  
Zhigen Chen ◽  
Yuxuan Gong ◽  
Huwei Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Analytical Study ◽  
Energy Dispersive Spectrometry ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Ancient China ◽  
X Ray ◽  
Unique Style ◽  
Scanning Electron

AbstractWith exquisite design and unique style, the painted sculptures of Tutang Buddha and two attendants Buddha in Jingyin Temple are precious cultural heritages of China. The sculpture of Tutang Buddha, which was carved from a mound and painted by ancient craftsmen, was rarely found in ancient China. However, due to natural and human factors, the sculptures were severely damaged. Obviously, they require urgent and appropriate protection and restoration. In this study, samples taken from the sculptures were analysed through multiple analytical techniques, including scanning electron microscopy with energy dispersive spectrometry (SEM–EDS), Raman spectroscopy, X-ray diffraction (XRD), optical microscopy (OM) and granulometry. The analysis results enable us to infer the techniques used by the craftsmen in making the sculptures and provide a reliable evidence for the conservation and future protection of these and similar sculptures.

The Effect of Sodium Silicate Concentration on the Properties of the Coating Formed on Pure Zirconium by Microarc Oxidation Coating Technique

2012 ◽  
Vol 445 ◽  
pp. 637-642 ◽  
Author(s):  
Y. Gencer ◽  
M. Tarakci ◽  
S. Cengiz ◽  
K.O. Gunduz
Keyword(s):  
Surface Roughness ◽  
Sodium Silicate ◽  
Zirconium Oxide ◽  
Microarc Oxidation ◽  
Phase Content ◽  
Oxide Coatings ◽  
Silicate Concentration ◽  
X Ray ◽  
Pure Zirconium ◽  
Scanning Electron

In this study, zirconium oxide coatings were formed on pure zirconium by microarc oxidation technique with the electrolytes containing KOH and different amounts of sodium silicate (0-40 gr/lt) for the same coating duration of 2 hours. The microstructure, surface roughness, phase content and chemical composition of the coatings were characterized by using scanning electron microscopy, profilometery and X-ray diffractometry. It was found that the coatings on surface of zirconium consist of monoclinic ZrO2 (m-ZrO2) and tetragonal ZrO2 (t-ZrO2) phases and the addition and increasing sodium silicate concentration in the electrolyte increases amount of t-ZrO2 phase. The coatings were well adhered to Zr substrate with some cracks and porosities in the coating for all concentrations of sodium silicate. The coating thickness and surface roughness increased with sodium silicate concentration in the electrolyte. A glaze like Si rich structure and its increase with Si rate was evident in the outermost region of the coating.

Effect of oxidation time on the microstructure and properties of ceramic coatings prepared by microarc oxidation on 7A04 superhard aluminum alloy

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744026
Author(s):  
Feng Xiao ◽  
Hui Chen ◽  
Jingguo Miao ◽  
Juan Du
Keyword(s):  
Aluminum Alloy ◽  
Microarc Oxidation ◽  
Ceramic Coatings ◽  
Ceramic Layer ◽  
X Ray Diffraction ◽  
Oxidation Treatment ◽  
X Ray ◽  
Metallurgical Bonding ◽  
Dense Ceramic ◽  
Morphology Of Surface

Under the sodium aluminates’ system, microarc oxidation treatment was conducted on the superhard aluminum alloy 7A04 for different times. The microstructure of microarc oxidation ceramic layer was investigated by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influences of different oxidation times on the adhesion strength of ceramic layer and substrate, the morphology of surface and cross-section, the phase composition and the electrochemical properties were studied. The results indicated that the connection of the coating and substrate appears to be metallurgical bonding and dense ceramic layer, and the surface is in a “volcanic vent” morphology, which is composed of [Formula: see text]-Al2O3 and little [Formula: see text]-Al2O3. The corrosion resistance of ceramic layer is improved significantly in contrast with that of the substrate.

Study on Linear Segregation of ZL205A Alloy

2021 ◽  
Vol 1020 ◽  
pp. 8-12
Author(s):  
Wu Hu ◽  
Ke Zhu ◽  
Meng Wang ◽  
Wei Dong Huang ◽  
Jian Min Zeng
Keyword(s):  
Aluminum Alloy ◽  
Wall Thickness ◽  
Hot Spots ◽  
Energy Dispersive Spectrometer ◽  
High Strength ◽  
X Ray ◽  
Thermal Cracks ◽  
Zl205a Alloy ◽  
Solidification Speed ◽  
Scanning Electron

Linear segregation of high strength aluminum alloy ZL205A castings were studied by X-ray Nondestructive testing, scanning electron microscope and energy dispersive spectrometer. It is found that the linear segregation occurs at the large wall thickness of the casting and/or at the place where the wall thickness is in transition. Segregation element is mainly Cu, which exists as compound θ (Al2Cu) phase. The formation of linear segregation is related to the flow of Cu-rich melt in the late solidification period, while the occurrence of thermal cracks promotes the formation of linear segregation. The formation of linear segregation of the casting can be effectively prevented by eliminating hot spots of the casting, refining crystal grains and increasing solidification speed of the casting.

Process Study on Prepared Al2O3-TiB2 Composite Coating by Reactive Spray

2012 ◽  
Vol 472-475 ◽  
pp. 309-312
Author(s):  
Xiao Ping Zhou ◽  
Ming Li ◽  
Xin Zhou
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aluminum Alloy ◽  
Composite Coating ◽  
Milled Powder ◽  
X Ray ◽  
Phase Constituent ◽  
Process Study ◽  
High Microhardness ◽  
Scanning Electron

The microstructures and properties of Al2O3-TiB2 composite coating on the surface of the aluminum alloy by reactive spraying was studied. The influences of mechanical alloying and spraying temperature on the phase constituent and microstructure of the composite were analyzed by X-ray diffractometry(XRD) and scanning electron microscopy(SEM). The results indicate that Al2O3-TiB2 composite coating is obtained by plasma spraying using milled powder of Al，TiO2，B2O and B2O3. The coating possesses high microhardness of 1300 HV0.1.

Preparation and Characterization of Tin Doped Tetra-Pod Shaped Zinc Oxide

2005 ◽  
Vol 475-479 ◽  
pp. 1161-1164 ◽  
Author(s):  
Jing Jing Liu ◽  
Zuo Wan Zhou ◽  
Kai Wang ◽  
Yanxia Li
Keyword(s):  
Zinc Oxide ◽  
Growth Process ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Crystal Growth Process ◽  
Zno Crystal ◽  
Weight Proportion ◽  
Scanning Electron

Tin doped tetra-pod shaped ZnO (T-ZnO) were fabricated by equilibrant airflow reaction method. The microstructure of tin doped T-ZnO was characterized by X-ray Diffraction analysis and Scanning Electron Microscope. The results demonstrated that most of tin acted as a catalyst during the ZnO crystal growth process and the others reacted with ZnO to generate Zn2SnO4. Tin had catalytic influences on the morphology of T-ZnO, which promoted predominant growth on the c axis of ZnO crystal at the addition of 15% in weight and advanced the growth on the a axis at higher weight proportion.

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