Surface analysis of Zircaloy-2 implanted with carbon before and after oxidation in air at 500 °C

2006 ◽  
Vol 56 (2) ◽  
pp. 112-120 ◽  
Author(s):  
D.Q. Peng ◽  
X.D. Bai ◽  
F. Pan ◽  
H. Sun ◽  
B.S. Chen
Keyword(s):  
Surface Analysis ◽  
Before And After ◽  
Oxidation In Air

The oxidation of graphite I. The observation of oxidation on synthetic graphite before and after irradiation

1963 ◽  
Vol 274 (1358) ◽  
pp. 386-394 ◽  
Keyword(s):  
Grain Boundaries ◽  
Etch Pits ◽  
Thin Sections ◽  
Pit Formation ◽  
Irradiated Graphite ◽  
Before And After ◽  
Synthetic Graphite ◽  
Oxidation In Air ◽  
The Individual ◽  
Oxidative Attack

Ultra-thin sections of a synthetic graphite have been examined in the electron microscope before and after oxidation in air at a temperature of 500 °C. In unirradiated material, micrographs of individual areas showed that oxidative attack occurred at grain boundaries and at pores between individual crystallites. Parallel experiments on material which had been irradiated to a dose of 8.7 x 10 19 n .v .t. again showed etching at pores and at grain boundaries, but, in addition, in the majority of specimens, a shallow surface pitting of the entire (0001) faces of the individual crystallites took place. The density of these shallow pits varied from 5 x 10 10 /cm 2 to 5 x 10 u /cm 2 . Variations in reaction rate were observed and were traced to impurity which, especially when metallic, greatly increased the oxidation rate. In unirradiated graphite, this impurity appeared to be absorbed only at pores and intercrystallite boundaries, oxidation effects being observed only at these sites. In irradiated material impurity was also absorbed at sites on the (0001) crystal faces where oxidation produced etch pits of widely varying depth and density. Channelling of the (0001) layer nets occurred in both irradiated and unirradiated specimens. Annealing of the irradiated graphite at 650 °C for 1 h produced no significant change in the pattern of attack by oxygen. The observed etch pit density measured on the (0001) layer nets was 8 x 10 10 cm 2 . A mechanism for pit formation relating pit density and vacancy content is proposed. The general appearance of irradiated samples differed from the unirradiated in that the well-defined moire patterns characteristic of thin sections of synthetic graphite were absent in irradiated samples, but reappeared when the samples were annealed at 650 °C. This change is related to the known behaviour of interstitial atoms in graphite on annealing the materials,

Article

1999 ◽  
Vol 77 (10) ◽  
pp. 1678-1689 ◽  
Author(s):  
Mark E McGovern ◽  
Michael Thompson
Keyword(s):  
Surface Analysis ◽  
Photoelectron Spectroscopy ◽  
Spectroscopic Analysis ◽  
Thiol Group ◽  
High Coverage ◽  
X Ray ◽  
Functionalized Surfaces ◽  
Before And After ◽  
Substrate Surfaces ◽  
Thiol Functionalization

The immobilization of biomolecules on substrate surfaces for biosensor development requires linking molecules that must meet a specific set of criteria. Two such agents based on bifunctional alkyltrichlorosilane structures, 1-bromo-11-(trichlorosilyl)-undecane and 1-(thiotrifluoroacetato)-11-(trichlorosilyl)-undecane, are employed to generate thiol-functionalized surfaces either by nucleophilic substitution followed by reduction (bromine-containing derivative) or deprotection (fluorine-containing compound). Both molecules have been attached to the surfaces of silicon wafers in conjunction with the diluent silane, octyltrichlorosilane. X-ray photoelectron spectroscopic analysis in the conventional and angle-resolved modes confirms that both silanization reactions were successful. The alkyl-bromine surfaces were subjected to treatment with a set of nucleophilic reactants followed by reduction and derivatization with trifluoroacetic anhydride. The latter in conjunction with surface analysis was used to estimate the level of thiol functionalization achieved. The fluorine-containing undecane surface has been studied by surface analysis both before and after deprotection of the thiol group by hydroxylamine solution. The results indicate that a high coverage of the surface was found for the protected moiety, with approximately 10% of the trifluoro acetate groups remaining after the deprotection procedure.Key words: bifunctional silanes, thiol surface functionalization, biomolecule immobilization, X-ray photoelectron spectroscopy.

Protective Zirconia Thin Films on Metal Substrates.

1992 ◽  
Vol 271 ◽  
Author(s):  
Andrea Tomasi ◽  
Paolo Scardi ◽  
Fabio Marchetti
Keyword(s):  
Thin Films ◽  
Protective Coatings ◽  
Protective Action ◽  
Depth Profiling ◽  
Temperature Oxidation ◽  
Deposition Parameters ◽  
Before And After ◽  
Profiling Techniques ◽  
Oxidation In Air ◽  
Chemical Distribution

ABSTRACTStabilized Zirconia thin films were deposited by R. F. Magnetron Sputtering onto iron substrates. Deposition parameters such as gas pressure and R. F. voltage were optimized to obtain homogeneous and well adherent protective coatings. The morphology and structure of films before and after thermal treatments were investigated by Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Thermogravimetrical Analysis (TGA).Auger Electron Spectroscopy (AES) depth profiling techniques were used to obtain the chemical distribution of the elements in order to study the influence of two important parameters on the adhesion of the ceramic: the presence of a thin layer of native metal oxide and the residual surface roughness after polishing.The effectiveness of coatings to protect the metal substrate against high temperature oxidation in air was evaluated by thermogravimetrical analysis at 773K. The protective action of the ceramic film was well demonstrated.

Wear behaviour of Ti6Al4V alloy blasted with zirconia/hydroxyapatite powders

2014 ◽  
Vol 66 (1) ◽  
pp. 106-110 ◽  
Author(s):  
A.B. Hazar Yoruç ◽  
O. Elkoca ◽  
Harika Ekşioğlu Yıldız ◽  
Ahmet Koyun
Keyword(s):  
Surface Roughness ◽  
Weight Loss ◽  
Surface Analysis ◽  
Wear Behavior ◽  
Ti6al4v Alloy ◽  
Wear Behaviour ◽  
Content Type ◽  
Implant Materials ◽  
Before And After

Purpose – The purpose of this paper is to investigate the effect of blasting treatment with zirconia/hydroxyapatite powders on the surface roughness, in vitro bioactivity and wear behavior of Ti6Al4V alloy (Grade V). Design/methodology/approach – Ti6Al4V specimens were sandblasted with ZrO2 and HA [Ca10(PO4)6(OH)2] powders in a commercial blasting cabinet. Surface analysis was performed evaluating eroded surfaces by scanning electron microscopy. Roughness surface analysis of the samples was performed with a surface roughness tester and in vitro bioactivity of titanium surfaces was examined in the simulated body fluid (SBF) solution before and after blasting. Wear resistance is evaluated by the weight loss during the test. Findings – The highest value of surface roughness is obtained with a mixture of 25 percent ZrO2+75 percent HA (Z25). Z25 exhibited also lower weight loss than Ti6Al4V and other treated samples. These results indicate that surface treatment with 25 percent ZrO2+75 percent HA provides the highest amount of HA adhesion on the surface of Ti6Al4V implant. Finally, the sample surfaces were contacted with SBF solutions for seven days, and Ca/P accumulation was identified on the blasted surfaces. ZrO2/HA blasting method can be used to improve the wear characteristics and the biocompatibility of the implant materials. Originality/value – The paper provides information about the effect of ZrO2/HA blasting treatment on the surface properties, in vitro bioactivity and wear behavior of Ti6Al4V implant materials.

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