Effect of Substrate Surface Oxidation on Tritium Permeation Barrier Properties of MOD Er2O3 Coating

2011 ◽  
Vol 60 (4) ◽  
pp. 1576-1579 ◽  
Author(s):  
Dongxun Zhang ◽  
Teruya Tanaka ◽  
Takeo Muroga
Keyword(s):  
Substrate Surface ◽  
Surface Oxidation ◽  
Barrier Properties ◽  
Tritium Permeation

Characterization of Alloy 214 After Exposure to Superheated Steam at 800 °C

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Nick Tepylo ◽  
Rainier Garcia Sanchez ◽  
Xiao Huang
Keyword(s):  
Weight Gain ◽  
Supercritical Water ◽  
Weight Change ◽  
Superheated Steam ◽  
Substrate Surface ◽  
Surface Oxidation ◽  
Metal Substrate ◽  
Cr Content

In this study, an Al-containing alloy 214 was evaluated in superheated steam at 800 °C for a duration of 600 h. The purpose of using superheated steam was to simulate the supercritical water (SCW) condition at higher temperatures where no commercial SCW rig is currently capable of reaching (800 °C and beyond). After exposure to superheated steam, the weight change and surface oxidation were analyzed. Alloy 214 experienced greater weight gain than IN 625 and Ni20Cr5Al, due to its low Cr content. Formation of both Cr2O3 and Al2O3 was observed on the surface after 300 and 600 h of exposure. However, as exposure progressed, more Ni and Mn-containing spinel started to form, signaling Cr and Al depletion on the metal substrate surface.

scholarly journals Enhanced Adhesion Strength of Pt/γ-Al2O3 Catalysts on STS-444 Substrate via γ-Al2O3 Intermediate Layer Formation: Application for CO and C3H6 Oxidation

Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 38
Author(s):  
Seung-Hee Ryu ◽  
Cheol Hong Hwang ◽  
Hojin Jeong ◽  
Giyeong Kim ◽  
Sung Il Ahn ◽  
...  
Keyword(s):  
Adhesion Strength ◽  
Intermediate Layer ◽  
Substrate Surface ◽  
Surface Oxidation ◽  
Catalytic Performance ◽  
Pack Cementation ◽  
Oxidation Reactions ◽  
Monolithic Catalysts ◽  
Simultaneous Oxidation ◽  
Potential Applications

Pt/γ-Al2O3 catalysts coated on honeycomb-shaped stainless STS-444 steel substrates with a γ-Al2O3 intermediate layer were prepared using a conventional washcoating method. The intermediate layer was formed on the substrate surface through oxidation using pack cementation. The monolithic catalysts with the intermediate layer were fabricated for potential applications to pre-turbocharger catalysts, which suffer from severe conditions such as vibrations of the engine and high flow rates of exhaust gas. Adhesive strength tests and simultaneous oxidation reactions of CO and C3H6 were carried out for the Pt/γ-Al2O3 monolithic catalysts with and without the intermediate layer. The catalysts with an intermediate layer showed much stronger adhesion than the catalysts without an intermediate layer. Thus, the formation of a γ-Al2O3 intermediate layer by surface oxidation through pack cementation facilitated a significant enhancement of the catalyst adhesion strength without catalytic performance degradation.

Tritium-permeation-barrier properties of erbium oxide (TPB) coating on CLAM steel

2019 ◽  
Vol 138 ◽  
pp. 347-351 ◽  
Author(s):  
Shuai Liu ◽  
Xin Ju ◽  
Jie Qiu ◽  
Guoxiang Chen ◽  
Jun Sun ◽  
...  
Keyword(s):  
Barrier Properties ◽  
Erbium Oxide ◽  
Clam Steel ◽  
Tritium Permeation

Facile fabrication of hydrophobic cellulosic paper with good barrier properties via PVA/AKD dispersion coating

2019 ◽  
Vol 34 (4) ◽  
pp. 516-524
Author(s):  
Zhenghui Shen ◽  
Soojin Kwon ◽  
Kyudeok Oh ◽  
Araz Rajabi Abhari ◽  
Hak Lae Lee
Keyword(s):  
Transmission Rate ◽  
Substrate Surface ◽  
Barrier Properties ◽  
Porous Polymer ◽  
Alkyl Ketene Dimer ◽  
Resistance Level ◽  
Water Contact ◽  
Cellulosic Fibers ◽  
Base Paper ◽  
Cellulosic Paper

Abstract Due to the micro-sized pores on cellulosic substrate surface and the hygroscopic nature of cellulosic fibers, paper has poor barrier properties. Dispersion coating can improve the barrier properties of cellulosic paper noticeably by forming a continuous, non-porous polymer film on paper surface. In this work, the excellent film-forming performance of polyvinyl alcohol (PVA) was used to seal the surface pores of paper, thus enhancing the barrier properties. Alkyl ketene dimer (AKD) was also added as a coating component to improve the water resistance of paper. Results showed that after PVA/AKD coating hydrophilic base paper changed to hydrophobic one, as proved by water contact angle (WCA) measurements. The water vapor transmission rate (WVTR) of base paper decreased sharply from 543 g/m2·day to 2 g/m2·day in the case of PVA/AKD triple coating, where the threshold of WVTR was reached. Meanwhile, the pristinely non-grease resistant base paper converted to a product with the highest grease resistance level. Furthermore, both elongation at break and tensile strength of base paper improved markedly after PVA/AKD coating. It was concluded that these improved properties were contributed by the combined use of PVA and AKD in the coating.

Improvement of power performance in planar type AlGaAs/GaAs MESFET by substrate surface oxidation

2003 ◽  
Vol 216 (1-4) ◽  
pp. 542-548 ◽  
Author(s):  
T. Kagiyama ◽  
Y. Saito ◽  
K. Otobe ◽  
S. Nakajima
Keyword(s):  
Substrate Surface ◽  
Surface Oxidation ◽  
Power Performance ◽  
Gaas Mesfet

Electron microscopy studies of plasma-sprayed materials

1983 ◽  
Vol 41 ◽  
pp. 70-71
Author(s):  
K.R. Subramanian ◽  
A.H. King ◽  
H. Herman
Keyword(s):  
Plasma Spraying ◽  
Substrate Surface ◽  
Flame Temperature ◽  
Ceramic Coatings ◽  
Metallic Substrates ◽  
Hot Plasma ◽  
Almost All ◽  
Plasma Sprayed ◽  
Hostile Environments ◽  
Plasma Spraying Process

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.

Organization of tight junctions in the choroid plexus epithelium

1978 ◽  
Vol 36 (2) ◽  
pp. 336-337
Author(s):  
B. Van Deurs ◽  
J. K. Koehler
Keyword(s):  
Choroid Plexus ◽  
Present Report ◽  
Freeze Fracture ◽  
Barrier Properties ◽  
Cell Junctions ◽  
Structural Basis ◽  
Apical Surface ◽  
Choroid Plexus Epithelium ◽  
Solid Nitrogen ◽  
Special Composition

The choroid plexus epithelium constitutes a blood-cerebrospinal fluid (CSF) barrier, and is involved in regulation of the special composition of the CSF. The epithelium is provided with an ouabain-sensitive Na/K-pump located at the apical surface, actively pumping ions into the CSF. The choroid plexus epithelium has been described as “leaky” with a low transepithelial resistance, and a passive transepithelial flux following a paracellular route (intercellular spaces and cell junctions) also takes place. The present report describes the structural basis for these “barrier” properties of the choroid plexus epithelium as revealed by freeze fracture.Choroid plexus from the lateral, third and fourth ventricles of rats were used. The tissue was fixed in glutaraldehyde and stored in 30% glycerol. Freezing was performed either in liquid nitrogen-cooled Freon 22, or directly in a mixture of liquid and solid nitrogen prepared in a special vacuum chamber. The latter method was always used, and considered necessary, when preparations of complementary (double) replicas were made.

Growth of hematite by surface oxidation of olivine

1988 ◽  
Vol 46 ◽  
pp. 800-801
Author(s):  
S. McKernan ◽  
C. B. Carter
Keyword(s):  
Electron Microscope ◽  
Surface Oxidation ◽  
Thin Foil ◽  
Nucleation And Growth ◽  
Ion Milling ◽  
Annealed Material ◽  
Thin Foils ◽  
Natural Olivine ◽  
Approximate Composition ◽  
Second Phases

The oxidation of natural olivine has previously been performed on bulk samples and the reactions followed by preparation of TEM specimens from the annealed material. These results show that below ∼1000°C hematite and amorphous silica are formed, particularly around dislocations. At higher temperatures magnetite and some enstatite-like phase are formed. In both cases the olivine is left almost totally Fe depleted. By performing the oxidation on characterized thin TEM specimens it is possible to obtain more information on the nucleation and growth of the second phases formed. The conditions in a thin foil, however, are very different from those in the bulk especially with regard to surface effects. The nucleation of precipitates in particular may be expected to occur differently in these thin foils than in the bulk.TEM specimens of natural olivine (approximate composition Mg+Fe+Si2o4) which had been annealed at 1000°C for 1 hr were prepared by mechanical polishing and dimpling, followed by Ar ion milling to perforation. The specimens were characterized in the electron microscope and then heated in air in alumina boats to 900°C for between 30 and 180 minutes.

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