Effects of the iron-oxide layer in Fe-FeO-MgO-Fe tunneling junctions

2003 ◽  
Vol 68 (9) ◽  
Author(s):  
X.-G. Zhang ◽  
W. H. Butler ◽  
Amrit Bandyopadhyay
Keyword(s):  
Iron Oxide ◽  
Oxide Layer ◽  
Tunneling Junctions

The presence of an iron oxide layer at the enamel/steel interface in one-coat porcelain enamelling

1983 ◽  
Vol 18 (2) ◽  
pp. 599-604 ◽  
Author(s):  
D. Ritchie ◽  
H. A. Schaeffer ◽  
D. White
Keyword(s):  
Iron Oxide ◽  
Oxide Layer

Iron‐iron oxide layer films

1984 ◽  
Vol 55 (6) ◽  
pp. 2628-2630 ◽  
Author(s):  
R. R. Ruf ◽  
R. J. Gambino
Keyword(s):  
Iron Oxide ◽  
Oxide Layer ◽  
Iron Iron

scholarly journals Iron-based inorganic–organic hybrid and superlattice thin films by ALD/MLD

2015 ◽  
Vol 44 (44) ◽  
pp. 19194-19199 ◽  
Author(s):  
A. Tanskanen ◽  
M. Karppinen
Keyword(s):  
Thin Films ◽  
Iron Oxide ◽  
Oxide Layer ◽  
Layer By Layer ◽  
Organic Layers ◽  
Organic Hybrid ◽  
Layer Deposition ◽  
Hybrid Thin Films ◽  
Iron Based ◽  
Deposition Processes

Here we present novel layer-by-layer deposition processes for the fabrication of inorganic–organic hybrid thin films of the (–Fe–O–C6H4–O–)n type and also superlattices where N thicker iron oxide layer blocks alternate with monomolecular-thin organic layers.

Functional Iron Oxide (Fe2O3) Nanoparticles Based Gas Sensor Operating at High Temperature

2019 ◽  
Author(s):  
Ricky W. Chuang
Keyword(s):  
High Temperature ◽  
Iron Oxide ◽  
Oxide Layer ◽  
Gas Sensor ◽  
Iron Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Fe2o3 Nanoparticles ◽  
Oxidation Reduction ◽  
Enclosed Chamber ◽  
Different Gases

The highly responsive gas sensor based on a metal-oxide-semiconductor (MOS) configuration which is conformally coated with iron oxide (Fe2O3) nanoparticles is hereby designed, fabricated, and systematically characterized for this study. The iron oxide nanoparticles are prepared by mixing altogether the respective amounts of FeCl2-4H2O, FeCl3-6H2O, and NaOH in terms of different molar ratios. The iron oxide overcoated gas sensor thus fabricated has been electronically probed in an enclosed chamber under a high-temperature condition during which the different gases are fed in individually and selectively. The presence of a particular gas is duly sensed by monitoring the changing magnitude of the current extracted from the sensor. The enhanced sensitivity of the MOS-based sensor overlaid with the Fe2O3 nanoparticles is attributed to a large surface area typically associated with nanoscale particles. The fabrication of the MOS-based sensor is entirely CMOS compatible and can be summarized as follows. First, the 400μm-thick silicon wafer is first RCA cleaned and then both sides of the wafer are coated with 800nm-thick oxide layer using high-pressure oxidation furnace. Next, a series of photolithographic steps followed by electron-beam-evaporated titanium lift-off is implemented to realize the heater pattern. Afterward, the resultant heater pattern is overcoated with a 400nm-thick oxide layer using plasma-enhanced chemical vapor deposition (PECVD). In order to open up an area for the subsequent deposition of iron oxide nanoparticles-embedded material while leaving the titanium heater protected by the same oxide layer, necessary photolithographic and buffered oxide etching (BOE) steps are performed. Finally, the interdigitated electrodes are deposited followed by injecting the viscous Fe2O3 nanoparticles-embedded solution over the electrodes. Once the sensor is successfully fabricated, the very sensor is placed on a temperature-controlled sample platform maintained at the desired temperature within an enclosed chamber. The entire sensor characterization is performed at a temperature of 300 degree Celsius. The operating mechanism of the sensor is intimately dependent on the oxidation-reduction reaction between the injected gas and Fe2O3 nanoparticles-embedded sensing film. As can be shown in the following figure, the ethanol (C2H5OH) gas vapor is functioned as a reducing agent, while nitrogen dioxide (NO2) gas, on the other hand, is behaved as an oxidizing agent instead. As ethanol gas vapor is injected, the oxygen ions of the ethanol produced at high temperature are converted back to the neutral oxygen atom while releasing the captured electrons back to to the iron oxide sensing film, thereby causing the detected current to go up. On the other hand, nitrogen dioxide is behaved as an oxidizing agent instead of by oxidizing the Fe2O3 film and grabbing the electrons away, thereby causing the detected current to drop in response to the presence of the NO2 gas vapor. Consequently, the reversing current-versus-time patterns associated with C2H5OH and NO2 are thus detected, which verify the different oxidation-reduction mechanisms associated with these two different gases. The optimization in the design of the iron oxide nanoparticles coated sensor in order to enhance the sensitivity and the response time in the detection of the different gases is currently being pursued and the subsequent results will be expected to publish elsewhere.

Effects of Laser Radiation on the Wetting and Diffusion Characteristics of Kovar Alloy on Borosilicate Glass

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Min Zhang ◽  
Y. Lawrence Yao ◽  
Chang Jun Chen ◽  
Panjawat Kongsuwan ◽  
Grant Brandal ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Diffusion Process ◽  
Oxide Layer ◽  
Borosilicate Glass ◽  
Glass Powder ◽  
Laser Surface ◽  
Holding Time ◽  
Diffusion Characteristics ◽  
And Diffusion ◽  
Kovar Alloy

The purpose of this study was to investigate the advantages of laser surface melting for improving wetting over the traditional approach. For comparison, kovar alloy was preoxidized in atmosphere at 700 °C for 10 min, and then wetted with borosilicate glass powder at 1100 °C with different holding time in atmosphere. The proposed approach used a Nd:YAG laser to melt the surface of the kovar alloy sample in atmosphere, then wetted with borosilicate glass powder at 1100 °C with the same holding time. The laser melted surface shows a decrease in contact angle (CA) from 47.5 deg to 38 deg after 100 min. X-ray photoelectron spectroscopy (XPS) analysis shows that the surface and adjacent depth have higher concentration of FeO for laser treated kovar (Kovar(L)) than that on traditional thermal treated kovar (kovar(P)). This is attributed to the following improved wetting and diffusion process. The adhesive oxide layer formed on kovar (L) may enhance the oxygen diffusion into the substrate and iron diffusion outward to form an outside layer. This is an another way to enhance the wetting and diffusion process when compared to the delaminated oxide scales formed on kovar (P) surface. The diffusion mechanisms were discussed for both approaches. Scanning electron microscope (SEM) revealed that an iron oxide interlayer in the joint existed under both conditions. Fayalite nucleated on the iron oxide layer alloy and grew into the glass. In both cases, neither Co nor Ni were involved in the chemical bonding during wetting process. The work has shown that laser surface melting can be used to alter the wetting and diffusion characteristics of kovar alloy onto borosilicate glass.

Investigations into fatigue failure in e-type fastening clips used in railway tracks

2020 ◽  
pp. 095440972096780
Author(s):  
Rashid Ali ◽  
Tauheed Shehbaz ◽  
Daniele De Felicis ◽  
Marco Sebastiani ◽  
Edoardo Bemporad
Keyword(s):  
Iron Oxide ◽  
Oxide Layer ◽  
Morphological Changes ◽  
Central Area ◽  
Weight Percent ◽  
Initiation Site ◽  
Electric Induction ◽  
Initiation And Propagation ◽  
Finishing Process ◽  
Lamellar Tearing

This study describes the investigations of failure in an e-type clip at the inside of rear arch, where the stresses are maximum owing to in-service loading and bending that occurs during forming operations. Visual inspection, stereomicroscopy, optical-microscopy and Scanning Electron Microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) have been used as the characterization techniques. The microstructural, morphological changes were compared both in the central area and close to the location of failure in e-clip. During primary heating for forming steel rod into e-clip shape, the oxidation and decarburization occurs which caused the formation and penetration of iron oxide. The average thickness of oxide layer was found to be 20 µm with localized areas, where the oxides penetrated up to depth of 50 µm. During forming and shot peening operations, the iron oxide ingested in material at the inside circumferential region of rear arch, which triggered the initiation and propagation of fatigue phenomenon in service. The SEM-EDS analysis and fractography confirmed the presence of iron oxide and pearlite lamellar tearing at the crack initiation site, respectively. It is suggested to use electric induction heating for forming of steel rod into e-clip shape or increased the silicon content from two to three weight percent, which minimize the thickness of oxide layer. The finishing process by adding air spray or tapping of the rod after heating will further help to remove the scale at the critical region before taking it up for mechanical forming operations.

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