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This contribution explores the applicability of nickel-based metallic foams as active electrodes and as electrocatalyst support materials. A comprehensive characterization of Ni and multi-component Ni-based foams is presented and includes the analysis of their structural, chemical, and electrochemical properties. Several materials and surface science techniques as well as electrochemical methods are used to examine the structural characteristics, surface morphology, and surface-chemical composition of these materials. X-ray photoelectron spectroscopy is employed to analyze the surface and near-surface chemical composition. The specific and electrochemically active surface areas (As, Aecsa) are determined using cyclic voltammetry (CV). The foams exhibit structural robustness typical of bulk materials and they have large As, in the 200 – 600 cm2 g–1 range. In addition, they are dual-porosity materials and possess both macro and meso pores. Nickel foam electrodes are applied as electrocatalysts for the oxidation of isopropanol. The process is studied under well-defined experimental conditions using cyclic voltammetry. The outcome of these experiments demonstrates that isopropanol oxidation requires the presence of -NiOOH on the Ni foam electrode. This surface oxide is generated at potentials near the potential of the isopropanol oxidation; however, the two processes do not occur exactly at the same potentials. The Ni foam anodes sustain a current density of ca. 2.6 mA cm–2 throughout an electrolysis time of up to 600 minutes without significant loss of electrocatalytic activity. Isopropanol is converted to acetone at a rate of ca. 5.6 mM per hour. The applicability of Ni foams as support materials for Pt is investigated. Platinum particles are deposited on Ni foam in low loading amounts via the chemical reduction of Pt2+ and Pt4+ originating from aqueous Pt salt solutions. The resulting Pt / Ni foams are characterized using electrochemical, analytical, and materials analysis techniques, including SEM to examine the morphology of the deposited material, CV to evaluate the Aecsa of the deposited Pt, and inductively coupled plasma optical emission spectrometry (ICP-OES) to determine the mass of deposited Pt. The Pt / Ni foams are applied as electrocatalysts for hydrogen evolution, hydrogen reduction, oxygen evolution, and oxygen reduction reactions in alkaline electrolyte. / Thesis (Ph.D, Chemistry) -- Queen's University, 2013-12-06 13:28:17.471

Porous sintered ceramic foam made of 99.8% Alumina (AL2O3) was investigated for grinding applications in metallic bearings. The properties of this alumina foam were investigated and correlated to the grinding performance in an I.D. grinding application. The mechanical properties, such as density and Young's Modulus, were correlated to grinding performance. The physical properties, investigated with Scanning Electron Microscope (SEM) analysis and a CT Scan, were used to study sintering behavior and porosity size and distribution. This work found an optimal friability and sintering temperature for the alumina foam grinding wheels. This will enable the alumina foam to become a viable grinding product and compete with the conventional vitrified products. This would be significant since the alumina foam has mainly one ingredient and is manufactured with a simpler process. It can also support a higher porosity than conventional grinding wheels, which has proven to provide better grinding performance and coolant access, keeping the work piece cooler and avoiding thermal damage.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Polymer bead foams are manufactured through a sintering process using foamed polymer beads. It is worth emphasis that the bead foam technology is the only process that can produce 3-dimensionally shaped foam products with ultra-low densities. This unique feature of bead foam process has been attracting enormous attentions from various foam industries. However the conventional bead foam processes still have some limitations associated with manufacturing productivity and safety during the treatment. This thesis deals with novel approaches to innovative and cost-effective manufacturing processes for polystyrene (PS) and polypropylene (PP) bead foam materials, based on thorough understanding of the scientific issues in bead foam technologies. This study also demonstrates the feasibility of new processes by conducting a series of foaming experiments such as batch foaming and continuous extrusion foaming as well as steam chest molding which is a critical common process for all bead foam products. In addition, this study aimed at developing new bead foam processes based on the relationship between the cellular structure and processing/material parameters. When it comes to expandable PS (EPS) bead process, research efforts have been made to eliminate n-pentane which has some disadvantages related to its flammability and low boiling temperature. In addition, the bi-celullar PS foams that feature the superior thermal-insulation property was manufactured through continuous extrusion foaming process. With regard to expanded PP (EPP) bead process, research efforts were focused on the development of cost-effective continuous foaming process in order to resolve the high cost issue of conventional EPP beads. These research strategies were designed on the basis of the comprehension of thermoplastic foaming, steam chest molding process and gas dissolution/diffusion phenomena. The results in the thesis provided considerable introductory and advanced knowledge about the bead foam technologies so that further promising researches can be performed to invent entirely new bead foam materials such as ultrahigh–temperature-durable bead foam products, biodegradable bead foams, other highly functional bead foam products aside from EPS and EPP bead foams.