Accelerated Service Life Research Articles

Fabrication of cerium-doped lead dioxide anode with improved electrocatalytic activity and its application for removal of Rhodamine B

The electrochemical properties of a titanium dioxide nanotubes/cerium-doped lead dioxide (TiO2-NTs/Ce-PbO2) anode and its removal of Rhodamine B (RhB) from aqueous solution were investigated. Cerium doping content and electrodeposition time were optimized to get the highest electrocatalytic activity. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were used to characterize the morphology, crystal structure and elemental states of the modified anode. The accelerated life test and linear sweep voltammetry indicated that TiO2-NTs/Ce-PbO2 possessed 2.3 times longer accelerated service life and higher oxygen evolution potential than TiO2-NTs/PbO2. The removal of RhB by TiO2-NTs/Ce-PbO2 anode was investigated under different conditions. It was found that a higher current density, acidic or quasi-neutral solution and the presence of chloride ions promoted the removal efficiency of RhB. The good electrocatalytic performance of TiO2-NTs/Ce-PbO2 makes it a promising anode for treatment of organic pollutants in aqueous solution.

Decolourization and degradation of C.I. Acid Red 73 by anodic oxidation and the synergy technology of anodic oxidation coupling nanofiltration

This work is conducted to study ability of anodic oxidation treatment azo dye C.I. Acid Red 73 (AR73) using the electrodes of Y doped Ti/SnO2–Sb electrodes prepared by thermal decomposition and Ti/SnO2–Sb electrodes prepared by electrodeposition. It has been shown that doping Y can enhances the electrochemical activity of the electrodes, but the accelerated service life was slightly reduced. Both the lifetime and electrochemical activity of Ti/SnO2–Sb electrodes prepared by electrodeposition in a new Sn–Sb electrodeposition bath outperform the Ti/SnO2–Sb electrodes prepared by thermal decomposition. Moreover, the effect of varying wastewater process indexes (initial pH (4–10), the addition of NaCl (0–9mM) and initial dye concentration (0.5–2.0gL−1)) on the performance of anodic oxidation using Ti/SnO2–Sb electrodes prepared by electrodeposition was investigated followed by the performance indicators analyses including color, chemical oxygen demand (COD), current efficiency and specific energy consumption. Finally, the synergy technology of anodic oxidation coupling nanofiltration was adopted to treat AR73 wastewater in order to overcome the low current efficiency of anodic oxidation. Preliminary results have shown that the synergy technology could cost-effectively treat AR73 wastewater.

Modelling of conditions for accelerated lifetime testing of Humidity impact on PV-modules based on monitoring of climatic data

Water is considered as an important degradation factor for PV-modules by causing hydrolysis of polymeric components, corrosion of glass and of metallic components like grids and interconnectors. The type approval testing of PV-modules according to the IEC standards takes water into account by means of the so called Damp-Heat test and the Frost-Thaw test. The test-conditions were designed long time ago and initially meant to reflect the service life of a module, but the type approval testing is not applicable for prediction of long-term durability behaviour, but a qualification test for the assurance of a minimum quality level.Basically absorption and mass transport of water into and within the module has to be considered. These phenomena depend on the ambient climate of the PV-module in use, the design (back-sheet, glass-glass, all polymer, e.g.), the operation conditions (rack-mounted, on rooftop, building integrated) and the material composition. We try to evaluate test conditions that are primarily based on the stresses occurring during the operation at specific locations by using monitored climatic data and applying phenomenological models for the estimation of the moisture load at the surfaces of PV-modules as function of the module temperature. A simple time transformation function was used for the design of appropriate damp-heat tests as accelerated service life tests. The evaluated testing times differ up to an order of magnitude for different climatic locations, depending on the kinetics of the dominant degradation processes.

Gas Transport in the Tire Aging Test and Intracarcass Pressure Issues

Abstract Development of the laboratory-based accelerated service life testing—“tire aging test”—encountered difficulties due to the complexity of multidisciplinary processes in the tire materials and structures while trying to induce thermooxidative degradation similar to that taking place in the “worst case” in-service. Preliminary experience with the oven aging at elevated temperatures showed that in some light truck tires damaging conditions occur in the form of sidewall blisters/detachments and casing separations due to inflation gas built up in interior tire layers during oven aging, even prior the roadwheel endurance testing (DOT HS 810 799, Research Report to Congress on Tire Aging), National Highway Traffic Safety Administration (NHTSA), Washington, D.C., 2007, http://www.cbsatlanta.com/download/2010/0512/23529107.pdf). Analysis and comprehensive modeling techniques are developed for gas diffusion and oxidation in the tire structure, with focus on the intracarcass pressure (ICP) build-up predictions. In finite element models, the temperature dependent diffusion properties are used with account for their high heterogeneity in different tire components. Results of transient simulations predict higher oxidation/degradation rate in the sidewall and a detrimental effect of ICP build-up for Load Range E tires—mainly due to excessive nitrogen permeation. Influence of the butyl liner barrier permeability and gauge is evaluated, as well as impact of other tire construction variations. Predicted trends agree with the available observations and measurements. ICP levels in simulations of the long-term gas diffusion under regular service conditions are significantly lower than in the oven aging test modeling. Mechanical aspects of the ICP-induced sidewall separation are also discussed. Modified aging test conditions are proposed that will greatly reduce the deleterious side-effect of the ICP buildup, as assessed in simulations.

Preparation and characterization of TiO 2-NTs/SnO 2-Sb electrodes by electrodeposition

The novel Sb-doped SnO 2 electrodes (TiO 2-NTs/SnO 2-Sb) have been prepared by anodization, electrodeposition and annealing. TiO 2 nanotubes (TiO 2-NTs) after Sb and Sn electrodeposited were characterized using field-emission scanning electron microscopy (FE-SEM). In contrast with the traditional Sb-doped SnO 2 coating prepared by thermal decomposition, the Sb-doped SnO 2 coating prepared by electrodeposition processes show more compact. X-ray diffraction (XRD) analysis indicates that the Sb-doped SnO 2 coating prepared by electrodeposition processes are firmly combined with the TiO 2-NTs formed on the Ti substrate. Accelerated service life tests reveal that the electrodeposition processes enhance the electrochemical stability of the Sb-doped SnO 2 electrode. The cyclic voltammetry analysis shows that TiO 2-NTs/SnO 2-Sb electrodes have higher overpotential for oxygen evolution and higher electrochemical porosity. Besides, the enhanced stabilization mechanism of the TiO 2-NTs/SnO 2-Sb electrode prepared by electrodeposition processes has been studied.

Study on the service life and deactivation mechanism of Ti/SnO2-Sb electrode by physical and electrochemical methods

The Sb doped tin dioxide electrode (Sb-doped SnO2) inter-layer was prepared using electroposition layer-by-layer onto a titanium plate, and the Sb-doped SnO2 surface catalytic layer (Ti/SnO2-Sb) was prepared using thermo-decomposition method. Accelerated service life tests were carried out in 0.5 M H2SO4 solution and 1.0 M NaOH solution, respectively. The deactivation mechanism of the electrodes is studied using oxygen evolution reaction (OER) as the reaction mode. Cyclic voltammetry test showed that the electrodes after accelerated life tests had no catalytic-oxidizing activity upon phenol. Electrochemical impedance spectroscopy (EIS) analysis exhibited that the membrane resistance of the deactivated electrode increases obviously in 0.5 M H2SO4 solution and 1.0 M NaOH solution, with the values of 1231 and 90.6 Ω, respectively. The structure, morphology and the content of the fresh and deactivated electrode were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray detector (EDX). This suggested that the Ti content on the electrode surface increases after deactivation, and TiO2 membrane with poor conductivity is grown on the electrode surface.

Preparation and properties of Ti/SnO 2–Sb 2O 5 electrodes by electrodeposition

Sb and Sn coatings were deposited on Ti substrate by the method of cathode deposition, and the Ti/SnO 2–Sb 2O 5 electrodes were obtained by annealing at different temperatures for 3 h. Ti/SnO 2–Sb 2O 5 coating was characterized using technique such as X-ray diffraction (XRD), and scanning electron microscopy (SEM). Ti/SnO 2–Sb 2O 5 electrode calcined at 550 °C exhibits the best catalytic capacity. Ti/SnO 2–Sb 2O 5 electrode obtained by electrodeposition had longer service life and faster degradation capacity compared with that obtained by dip-coating. Accelerated service life tests were carried out in 0.5 mol L − 1 H 2SO 4 solution with the current density of 100 mA cm − 2 . Service life of Ti/SnO 2–Sb 2O 5 electrode prepared in present study was 15 h, and it was only 0.14 h for Ti/SnO 2–Sb 2O 5 electrode obtained by dip-coating.

Preparation and Characterization of Antimony-Doped Tin Dioxide Electrodes. Part 1. Electrochemical Characterization

Antimony and antimony-platinum doped tin dioxide electrodes supported on titanium have been prepared by thermal decomposition. Ti/SnO2-Sb electrodes have a cracked-mud structure, typical of oxide electrodes prepared by thermal decomposition. The introduction of platinum in the oxide layer has a packing effect in the coating morphology. The electrochemical characterization of these electrodes has been performed in acid medium, and a relation between the roughness factor (measured from electrode capacitance) and electrochemical porosity (related to the voltammetric charge) has been established. The mechanism for the oxygen evolution reaction has been determined by Tafel measurements indicating that the electrodes prepared are nonactive electrodes. The electrocatalytic activity strongly depends on geometric factors, since the activity toward oxygen evolution increases with the electrochemical porosity. Anodic stability of Ti/SnO 2 electrodes has been checked with accelerated service life tests. The introduction of platinum in the oxide coating increases the service life by 2 orders of magnitude.

Dimensionally Stable Anode-Type Anode Based on Conductive p-Silicon Substrate

In the search for a good dimensionally stable anode-type electrode, p-silicon (1-3 mΩ cm) has been chosen as the substrate material due to its high anodic stability and its reasonable cost compared to titanium and tantalum. Several electrodes have been prepared by thermal decomposition at different temperature. The effect of preparation temperature on the morphological and electrochemical properties has been investigated by scanning electron microscopy analysis, X-ray diffraction, and cyclic voltammetries in 1 M showing that prepared at 450°C presents a high surface area and a low degree of crystallinity, while increasing the calcination temperature resulted in a decrease of true area and an increase in crystallite size. The activity of electrodes for simple electron transfer reactions and for complex electrode reactions has been also studied by cyclic voltammetry and linear polarization in solutions containing the hydroquinone/benzoquinone redox couple and various organic compounds (isopropanol, tert-butanol, methanol). Finally, the anodic stability of a electrodes prepared at 450°C has been tested by an accelerated service life test. p-Silicon based electrodes were shown to have the highest standardized service life compared with that of titanium- or tantalum-based electrodes. © 2003 The Electrochemical Society. All rights reserved.

Thirty minutes laser calcination method for the preparation of DSA ® type oxide electrodes

In this paper, a new approach for the preparation of dimensionally stable anodes DSA ® type oxide electrodes, using a CO 2 laser as a heat source, is proposed. Commercial composition of (TiO 2) 0.7(RuO 2) 0.3 was used for this feasibility study in which thermal decomposition of precursor chlorides, for the growth of a coating 2–3 μm thick, is carried out in 30 min. The resulting oxide layer presented the usual cracked-mud morphology that lasted 8 h in an accelerated service life test at 400 mA cm −2 , in a H 2SO 4 1 M solution. The results involving the effects of laser beam power and scan rate are examined. Voltammetric anodic charge was maximized by the combination of 15 W beampower, focal distance of 210 mm and beam scan rate of 35 mm s −1 . By cycling potential between 0.2 and 1.1 V vs SCE the oxide coating behaved as a capacitor capable of being charged and discharged reversibly and the cathodic/anodic charge ratio remained close to one. Currents related to oxygen evolution reaction were observed after 1.37 V vs SCE.

Evaluation of anode deactivation in chlor-alkali cells

Different techniques to evaluate catalytic activity and to quantify residual service life (RSL) have been applied to DSA® anodes used in chlor-alkali industrial cells. An accelerated service life test in sulfuric acid was used as a reference method. The results obtained through EIS, cyclic voltammetry and Ru content analysis of the catalytic layer confirm the results obtained with the accelerated test. There is a direct relation between the residual service life (RSL) thus obtained and the catalytic properties of the electrode. The different mechanisms of catalytic activity loss are discussed. An evaluation methodology is proposed to reduce maintenance costs of industrial cells.

Accelerated Corrosion Test for Aluminum-Zinc Alloy Coatings

Abstract An electrochemically monitored etching method has been developed to enable accelerated service life testing of aluminum/zinc alloy coatings with a dendritic microstructure. The method invo...

Accelerated Service Life Testing of Automotive Vehicles on a Test Course

SUMMARY The accelerated service life testing of automotive vehicles for durability to road roughness induced dynamic loads is often accomplished in the laboratory using road roughness simulation facilities [1–5]. However, such tests can also be accomplished by a carefully designed field operation on a test course [6], where both the speed of the vehicle and the roughness of die test course become variables that control the degree of the test acceleration. Field tests are generally harder to control than laboratory tests, but offer a greater degree of realism since the vehicle is fully operational during the test exactly as it will be in service. This paper formulates the criteria for accelerated service life tests on a test course, evaluates the assumptions that must be enforced to obtain valid results, and explores the sensitivity of the results to the critical test parameters, namely, the vehicle speed and the road roughness severity of the test course relative to the service environment.

Accelerated service life tests on injection lasers and transmitter modules

An analysis is made of the possibility of estimating reliably the service life of injection lasers from the results of accelerated tests carried out at elevated temperatures. An expression is obtained for the test acceleration coefficient under the following assumptions: the distribution of the initial parameters of the investigated lasers is described by the normal law; the distribution of failures under test is described by the logarithmic-normal law; the influence of temperature may be described by a thermally activated dependence. The efficiency of screening tests for the rejection of potentially unreliable samples is discussed and the possibility of finding an informative parameter suitable for the forecasting of service life is considered. The results obtained can be applied to accelerated service life tests on transmitter molecules.