Control and enhancement of the oxygen storage capacity of ceria films by variation of the deposition gas atmosphere during pulsed D.C. magnetron sputtering

In this study, nanostructured ceria (CeO2) films are deposited on Si(100) and ITO coated glass substrates by pulsed DC magnetron sputtering using a CeO2 target. The influence on the films of using various gas ambients, such as a high purity Ar and a gas mixture of high purity Ar and O2, in the sputtering chamber during deposition are studied. The film compositions are studied using XPS and SIMS. These spectra show a phase transition from cubic CeO2 to hexagonal Ce2O3 due to the sputtering process. This is related to the transformation of Ce4+ to Ce3+ and indicates a chemically reduced state of CeO2 due to the formation of oxygen vacancies. TGA and electrochemical cyclic voltammetry (CV) studies show that films deposited in an Ar atmosphere have a higher oxygen storage capacity (OSC) compared to films deposited in the presence of O2. CV results specifically show a linear variation with scan rate of the anodic peak currents for both films and the double layer capacitance values for films deposited in Ar/O2 mixed and Ar atmosphere are (1.6 ± 0.2) x 10-4 F and (4.3 ± 0.5) x 10-4 F, respectively. Also, TGA data shows that Ar sputtered samples have a tendency to greater oxygen losses upon reduction compared to the films sputtered in an Ar/O2 mixed atmosphere

Notch sensitivity of short and 2D plain woven glass fibres reinforced with different polymer matrix composites

This research article investigated the notch sensitivity of two different glass fibre architectures, namely short and 2D plain-woven glass fibres reinforced with unsaturated polyester and epoxy matrix composites fabricated by the hand lay-up technique. This was carried out through open hole tension tests at different ratios of the specimen hole diameter to the specimen with three different values (0.1, 0.2, 0.5) compared to the unnotched specimen. The notch sensitivity of these composites was evaluated using the residual tensile strength by the application of Whitney-Nuismer Mathematical Model. The results showed that by using polyester matrix, the notch sensitivity of composites reinforced with plain-woven glass fibre is higher than that of short glass fibre at different D/W ratios. On the other hand, on testing epoxy matrixes, the notch sensitivity of composites reinforced with plain-woven glass fibre is lower than that of short glass fibre at different D/W ratios

Control and enhancement of the oxygen storage capacity of ceria films by variation of the deposition gas atmosphere during pulsed DC magnetron sputtering

In this study, nanostructured ceria (CeO2) films are deposited on Si(100) and ITO coated glass substrates by pulsed DC magnetron sputtering using a CeO2 target. The influence on the films of using various gas ambients, such as a high purity Ar and a gas mixture of high purity Ar and O-2, in the sputtering chamber during deposition are studied. The film compositions are studied using XPS and SIMS. These spectra show a phase transition from cubic CeO2 to hexagonal Ce2O3 due to the sputtering process. This is related to the transformation of Ce4+ to Ce3+ and indicates a chemically reduced state of CeO2 due to the formation of oxygen vacancies. TGA and electrochemical cyclic voltammetry (CV) studies show that films deposited in an Ar atmosphere have a higher oxygen storage capacity (OSC) compared to films deposited in the presence of O-2. CV results specifically show a linear variation with scan rate of the anodic peak currents for both films and the double layer capacitance values for films deposited in Ar/O-2 mixed and Ar atmosphere are (1.6 +/- 0.2) x 10(-4) F and (4.3 +/- 0.5) x 10(-4) F, respectively. Also, TGA data shows that Ar sputtered samples have a tendency to greater oxygen losses upon reduction compared to the films sputtered in an Ar/O-2 mixed atmosphere. (C) 2015 Elsevier B.V. All rights reserved