Characterization of Micro-Arc Oxidation Coatings Formed on Biomedical Ni-Cr-Mo Alloy

2011 ◽  
Vol 337 ◽  
pp. 29-32
Author(s):  
Ji Lin Xu ◽  
De Zhen Yu ◽  
Jun Ming Luo
Keyword(s):  
Corrosion Resistance ◽  
Coated Sample ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Ni Content ◽  
Polarization Test ◽  
Micro Arc Oxidation ◽  
Chemical And Phase Compositions

In this paper, the micro-arc oxidation coatings formed on biomedical Ni-Cr-Mo alloy were characterized by surface and cross-sectional morphologies, chemical and phase compositions and corrosion resistance using scanning electron microscopy (SEM), Energy dispersive X-ray spectrometer (EDS), X-ray diffraction (XRD) and potentiodynamic polarization test, respectively. The results show that the coating is mainly composed of γ-Al2O3 crystal phase with a little Ni content. The coating possesses a typical porous surface and has a thickness of ~6 μm. The corrosion resistance of the coated sample is greatly improved compared with the uncoated Ni-Cr-Mo alloy.

EFFECT OF MICRO-ARC OXIDATION COATINGS ON CORROSION RESISTANCE AND MECHANICAL PROPERTIES OF CLOSED-CELL ALUMINUM FOAMS

2013 ◽  
Vol 20 (05) ◽  
pp. 1350053 ◽  
Author(s):  
XIANYONG ZHU ◽  
JIAAN LIU
Keyword(s):  
Corrosion Potential ◽  
Mechanical Test ◽  
Elemental Distribution ◽  
X Ray Diffraction ◽  
Compressive Properties ◽  
Aluminum Foams ◽  
X Ray ◽  
Closed Cell ◽  
Polarization Test ◽  
Micro Arc Oxidation

Micro-arc oxidation (MAO) coatings were prepared on closed-cell aluminum foams. The microstructure, elemental distribution and phase composition of the MAO coatings were analyzed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The corrosion resistances and compressive properties of the uncoated and coated aluminum foams were studied by electrochemical polarization test and mechanical test, respectively. The results show that the MAO coatings cover the surfaces of closed-cell aluminum foams. The average thickness of the MAO coatings is 7 μm. The MAO coatings are mainly composed of γ- Al 2 O 3 phase. The corrosion resistances of the closed-cell aluminum foams are improved by MAO treatment. The as-received foams show a low corrosion potential (-1.36 V), on contrary, the MAO coated foams get an increase corrosion potential (-0.78 V). But the MAO coated foams show the marginal variation in compressive strengths when the thickness of the coatings could be negligible compared with the total thickness of the foams.

Epitaxial growth and characterization of BP on Si(100) substrate for use in c-GaN study

2005 ◽  
Vol 891 ◽  
Author(s):  
Tomohiko Takeuchi ◽  
Suzuka Nishimura ◽  
Tomoyuki Sakuma ◽  
Satoru Matumoto ◽  
Kazutaka Terashima
Keyword(s):  
Epitaxial Layer ◽  
Careful Analysis ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Cross Sectional ◽  
X Ray ◽  
Si Substrates ◽  
Impurity Doping ◽  
Hall Effect Measurements

ABSTRACTBoronmonophosphide(BP) is one of the suitable materials for a buffer layer between the c-GaN(100) and Si(100) substrates. The growth of BP layer was carried out by MOCVD on Si(100) substrate of 2 inch in diameter. The growth rate was over 2 μm/h without any troubles such as the bowing or cracking. In addition, the thickness of BP epitaxial layer was uniform over a wide area. A careful analysis of x-ray diffraction suggested that the growth of BP epitaxial layer inherited the crystal orientation from Si(100) substrate. Cross-sectional TEM images showed some defects like dislocations near the interface between BP layer and Si substrate. The Hall effect measurements indicated that the conduction type of BP films grown on the both n-Si and p-Si substrates was n-type without impurity doping, and that the mobility and carrier concentrations were typically 357cm2/Vs and 1.5×1020cm−3(on n-Si) and 63cm2/Vs and 1.9×1019cm−3(on p-Si), respectively. In addition, c-GaN was grown on the substrate of BP/Si(100) by RF-MBE.

Effects of graphene on the microstructure and properties of MAO coatings formed on AA7050

2020 ◽  
Vol 111 (6) ◽  
pp. 463-468
Author(s):  
Bo Xu ◽  
Yafeng He ◽  
Xiangzhi Wang ◽  
Weimin Gan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Composite Coatings ◽  
Ceramic Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Scanning Electron

Abstract Ceramic coatings were prepared on the surface of 7050 highstrength aluminum alloy using micro-arc oxidation in an aluminate electrolyte with added graphene. To analyze the surface morphology, roughness, phase composition, and corrosion resistance, scanning electron microscopy, X-ray diffraction, X-ray photoelectron, and electrochemical measurements were used, respectively. The addition of 9 g · L-1 of graphene to the electrolyte decreased the micro-pore size of the composite coatings and improved the density. In addition, with the addition of graphene, the roughness was the lowest, and the corrosion resistance was significantly improved.

Microstructure and properties of rare earth CeO2-doped graphene composite coatings prepared by MAO on AA7050

2020 ◽  
Vol 111 (11) ◽  
pp. 923-930
Author(s):  
Yu Zong ◽  
Renguo Song ◽  
Tianshun Hua ◽  
Siwei Cai
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Composite Coatings ◽  
High Strength ◽  
Ceramic Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Doped Graphene ◽  
Micropore Size

Abstract In this paper, ceramic coatings were prepared on the surface of 7050 high strength aluminum alloy using a micro-arc oxidation process in a silicate electrolyte combined with the rare earth element cerium or graphene. To analyze the surface morphology, roughness, phase composition, and corrosion resistance, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, and electrochemical measurements were used, respectively. It was shown that the micropore size of the composite coatings, which mainly consisted of α-Al2O3 and γ-Al2O3, decreases and the density improved with the simultaneous addition of 4 g · L-1 of CeO2 and 10 g · L-1 of graphene to the electrolyte. In addition, with the addition of CeO2 and graphene, the roughness was the lowest and the corrosion resistance was significantly improved.

Structural and Electrical Characterization of TiB2/TiSi2 Bilayer Barrier Structure

1996 ◽  
Vol 441 ◽  
Author(s):  
G. Sade ◽  
J. Pelleg ◽  
A. Grisaru
Keyword(s):  
Diffusion Barrier ◽  
Vacuum Annealing ◽  
Schottky Diodes ◽  
Electrical Characterization ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Current Voltage ◽  
Thermal Stability Of

AbstractThe TiB2/TiSi2 bilayer is considered as a diffusion barrier in metallization system with Cu. The TiSi2 sublayer serves as a contact and also as an additional diffusion barrier against boron, which outdiffuses from TiB2 at high temperature annealing. The attempts to form TiSi2 by vacuum annealing of TiB2/Ti film, which was obtained by co-sputtering from elemental targets are described. The composition and the structure of the films were analyzed by Auger electron spectroscopy (AES), X-ray diffraction (XRD) and high-resolution cross-sectional TEM (HRXTEM). The Cu/TiB2/(Ti-Si)/n-Si contacts were investigated using current-voltage (I–V) on Schottky diode structures, which were prepared on n-type Si (100). The thermal stability of the TiB2/(Ti-Si) barrier was studied by structural and electrical analysis.It was observed that the lowest sheet resistance of 5.1 Ω/‪ was obtained after 850 °C annealing for 30 min, however the resulting Ti-Si layer is practically still amorphous and contains only a very small fraction of C54 TiSis in the form of microcrystallites. This layer also contained Ti5Si3 as indicated by XRD. The barrier height of Cu/TiB2/(Ti-Si)/n-Si Schottky diodes is ˜0.6 V and it does not show significant changes in the range 400–700 °C. Electrical monitoring is a very effective tool to detect deterioration of the barrier. No penetration is observed by AES at 700 °C, while the I–V curve shows changes in properties.

Synthesis and Characterization of A Metastable (SiC)aN4 Phase

1994 ◽  
Vol 354 ◽  
Author(s):  
C. Uslu ◽  
B. Park ◽  
D. B. Poker
Keyword(s):  
Cubic Phase ◽  
High Dose ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Position Sensitive ◽  
New Phase

AbstractA metastable C-Si-N compound has been synthesized by high dose N+ implantation into polycrystalline /8-SiC (cubic phase). The thin films formed upon 100 keV implantations were characterized with respect to various ion doses and target temperatures. X-ray diffraction with a position-sensitive detector and cross-sectional transmission electron microscopy revealed that the as-implanted surfaces contained ∼0.15 jttm thick continuously-buried amorphous layers. Rutherford backscattering spectroscopy showed that the peak concentration of nitrogen saturated up to approximately 54 at. % with increasing doses, suggesting a new phase formation.

scholarly journals Characterization of Si3N4-Al interface after corrosion tests

Cerâmica ◽  
2003 ◽  
Vol 49 (312) ◽  
pp. 223-227 ◽  
Author(s):  
C. dos Santos ◽  
S. Ribeiro ◽  
K. Strecker ◽  
C. R. M. da Silva
Keyword(s):  
Corrosion Resistance ◽  
Elevated Temperatures ◽  
Mechanical Stability ◽  
X Ray Diffraction ◽  
Crucible Material ◽  
High Corrosion Resistance ◽  
X Ray ◽  
High Corrosion ◽  
Metallurgical Processes

Silicon nitride is a covalent ceramic material of high corrosion resistance and mechanical stability at elevated temperatures. Due to these properties, its use in metallurgical processes, such as the casting of alloys, is increasing. Therefore, the characterization of the interface between Si3N4 and the casted metal is of great importance to investigate possible interactions, which might deteriorate the ceramic mould or contaminate the metal. In this work, the use of Si3N4 as crucible material for Al-casting has been studied, by investigating the corrosion attack of liquid Al at a temperature of 1150 ºC during 30 days in air. The interface was characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. It has been found that due to superficial oxidation two oxide layers form - SiO2 on Si3N4 and Al2O3 on Al - which effectively hinder further reactions under the conditions studied, confering high corrosion resistance to the Si3N4 crucible.

Deposition and characterization of crystalline conductive RuO2 thin films

1995 ◽  
Vol 10 (10) ◽  
pp. 2401-2403 ◽  
Author(s):  
Q.X. Jia ◽  
S.G. Song ◽  
S.R. Foltyn ◽  
X.D. Wu
Keyword(s):  
Thin Films ◽  
Room Temperature Resistivity ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Residual Resistance ◽  
X Ray ◽  
Transmission Electron ◽  
Residual Resistance Ratio ◽  
Temperature Resistivity

Highly conductive metal-oxide RuO2 thin films have been successfully grown on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition. Epitaxial growth of RuO2 thin films on YSZ and the atomically sharp interface between the RuO2 and the YSZ substrate are clearly evident from cross-sectional transmission electron microscopy. A diagonal-type epitaxy of RuO2 on YSZ is confirmed from x-ray diffraction measurements. The crystalline RuO2 thin films, deposited at temperatures in the range of 500 °C to 700 °C, have a room-temperature resistivity of 35 ± 2 μω-cm, and the residual resistance ratio (R300 k/R4.2 k) is around 5 for the crystalline RuO2 thin films.

Structural Characterization of P-I-N Diode Superlattice Structures Grown on , , and Orientation Si Substrates

1991 ◽  
Vol 220 ◽  
Author(s):  
P. M. Adams ◽  
R. C. Bowman ◽  
V. Arbet-Engols ◽  
K. L. Wang ◽  
C. C. Ahn
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Substrate Orientation ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron ◽  
Superlattice Structures ◽  
Strained Layer Superlattices

ABSTRACTP-I-N diodes whose intrinsic region consists of strained layer superlattices (SLS), separated by 40 nm Si spacers, have been grown by MBE on Si substrates with <100>, <110>, and <111> orientations. These structures have been characterized by x-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM). The dual periodicities in these structures produced unique XRD effects and the quality was highly dependent on substrate orientation. The <100> sample was in general free of defects, whereas the <110> and <111> specimens contained significant numbers of twins and dislocations.

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