1,720,993 research outputs found
Ni-free Alloys as Final Coatings: White Bronze Coatings on Copper
No full textJournal of Material Chemistr
Kinetics and equilibria in the hydrolisys of [Pt(terpy)Cl]Cl crystal and molecular structure of [Pt(terpy)OH]ClO4.H2O (terpy = 2,2'- 6,2''- terpyridine
No full textLa spettroscopia elettrochimica di impedenza (EIS). Parte IVa:: comportamento in ambiente aggressivo di patine artificiali su rame
No full textAn EIS study of the corrosion behaviour of PECVD coated brass substrate
No full textThe electrochemical impedance spectroscopy (EIS) was used to analyse the corrosion behaviour of the Ni plated brass (OT59) substrate covered by SiO2 coatings of different thickness. The specimens were immersed for long time (up to 168h) in a corrosive solution (synthetic swear). Plasma Enhanced Chemical Vapour Deposition (PECVD) technique was used to deposit SiO2 coatings: the aim was to obtain a surface treatment that prevents the release of Ni, an allergenic metal. The deposition was performed in RF (13.56 MHz) plasma with hexamethyldisiloxan (HMDSO) and O2 mixture at near room temperature without any solvents and without particular surface pretreatments. Different thickness of SiO2 film was obtained varying the time of plasma exposure.
The EIS technique was demonstrated to provide a wealth of information on the behaviour of the coated substrate over time, on condition that the obtained data are carefully interpreted. In this study the attention was focused on the equivalent circuit (EC) that models the electrode/solution interface. The electrical circuit elements were interpreted in terms of influence of the coating defects on the substrate corrosion, and to choose the best PECVD treatment
The Electrochemical Impedance Spectroscopy (EIS) - Part V: a first screening results to evaluation of Ni release as a preliminary remark of a new European rule for the glass industry.
No full textThe first screening results concerning the corrosion behaviour (Ni2+ release) of an industrial Ni-Ag arm series treated with two different galvanic coatings [Ni bright + flash of Au 23kt - Ni bright + flash Gun (Ni-Sn)], and then finished with three different final treatments (a coating of diluted epoxy varnish; a coating of standard epoxy varnish; a coating of standard epoxy varnish spread on an electrophoretic primer) was reported. The samples were analyzed by means of a technique - the Electrochemical Impedance Spectroscopy (EIS) - that gives some detailed indications not only on the corrosion rates, but also on the start and the mechanism of the corrosion process. First results, obtained by applying the EIS technique to a monitoring system meant to optimizing a pass or fail test, seem to be through-and-through promising: notwithstanding the sample immersion on the synthetic swear solution is a too drastic treatment in comparison with the common use of the metallic glass parts - which foresee in any case an occasional and/or preserved contact with the skin - the EIS technique is able to distinguish the sample that release or not Ni2+ below of 0.5 µg/cm² week. Before proposing to standardize the method, the obtained results will require the repeatability and reproducibility evaluation of data obtained until now
Tryptamine as a green iron corrosion inhibitor in 0.5M deaerated sulphuric acid
No full textThe inhibition effects of tryptamine (TA) on the corrosion behaviour of ARMCO iron in 0.5 M deaerated H2 SO4
(in the 25–55 ºC temperature range) was studied in both short and long time tests (1, 24 and 72 h) by means of potentiodynamic curves (PCM) and electro-chemical impedance spectroscopy (EIS). TA was found to be an effective ARMCO iron inhibitor, even at 55 ºC and 72 h, but only at 10 mM. At this concentration the inhibition percentages (IP%), calculated by PCM and EIS, ranged from 90% to 99% and did not diminish over time and as the temperature increased. TA adsorption followed Bockris–Swinkels' isotherm (x = 1). The thermodynamic data indicated that, in the more concentrated solutions, TA also chemisorbed on the iron surface
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
La spettroscopia elettrochimica di impedenza (EIS). Parte IIIa: Comportamento di strati anticorrosione depositati su argento via PECVD
No full text- …
