Mr Takin Ghavimi graduated with his MSc in Materials Science from University of Tehran. His MSc research at university of Tehran focused on synthesis of novel electrode materials used in solid oxide fuels cell technology. Mr Ghavimi’s recent work aims to increase the performance and functionality of solid oxide fuel cells by development of advanced cathode materials.

SrCoO3 composite is an important perovskite parent compound structure used for development of a many different functional materials. This composite can display mixed ionic and electronic conducting properties (MIEC) which can be useful for variety of applications including fabricating oxygen separating membranes, combustion catalysts and importantly cathode/anode materials for solid oxide fuel cells (SOFC), a device that can produce electricity directly from fuels. Depending on the operation temperature, oxygen partial pressure, thermal history and synthesis process, SrCoO3 can display multiple crystal structures. Important to our research the cubic structure of this material possesses the highest electronic and oxygen ionic conductivity with a reported total electronic conductivity of 160 S.cm-1 at 950°C. Additionally it is shown that substitution of various elements in the A and B site of this structure can increase the stability of this cubic lattice. In this study, A-site Barium doped SrCo0.8Fe0.2O3 (SCO) perovskite was synthesized by a novel co-precipitation method to stabilize its highly conductive cubic structure. For this synthesis, we have used a precipitation pH of at least 8 and a calcination temperature of 1000°C to achieve a pure perovskite phase. After synthetization, the obtained crystal structures were analyzed to evaluate the success of our co-precipitation method. Based on our XRD analysis the highest concentration of cubic crystal structure is achieved through substitution of 50% of the structure’s initial Strontium with Barium, additionally we report that our final structure exhibits a pure cubic phase at room temperature. Our novel method can help with producing a more stable cubic structure of SCO perovskite that be used in fabrication of materials with of higher electronic and oxygen ionic conductivity. These new materials can potentially increase the efficacy and performance of solid oxide fuel cells and eventually result in significantly lower costs for obtaining electricity.

Mr Takin Ghavimi graduated with his MSc in Materials Science from University of Tehran. His MSc research at university of Tehran focused on synthesis of novel electrode materials used in solid oxide fuels cell technology. Mr Ghavimi’s recent work aims to increase the performance and functionality of solid oxide fuel cells by development of advanced cathode materials.

A solid oxide fuel cell (SOFC) is an electrochemical conversion device that produces electricity directly from fuels. These fuel cells are comprised of ceramic electrolytes that can provide high efficiency in performance, fuel flexibility and overall low cost of the system. The main disadvantage of these systems is operating at high temperatures, which can result in (1) formation of an insulating layer, caused by reaction between electrode and electrolyte materials, (2) the necessity of using high cost interconnecting materials such as LsCrO3 and (3) possibility of crack formation caused by thermal coefficient mismatch between the electrode and electrolyte materials. In our work, we investigate methods of reducing the operating temperature of SOFCs, without sacrificing the system’s performance through fabrication of a new composites consisting of the two mostly used cathode materials BSCF (Ba0.5¬Sr0.5Co0.8Fe0.2O3-δ) and LSCF (La0.6Sr0.4Co0.2Fe0.8O3-δ). BSCF has the advantage of having high ionic conductivity, while LSCF is known to possess significantly higher electronic conductivity as well as better performance at operating temperatures of bellow 750 C. We aim to achieve both characteristics of the individual components. To produce the composite BSCF/LSCF we used our developed method of co-precipitation synthesis, which was followed by structure analysis using X-ray Diffraction (XRD). The synthesized composites were then used to fabricate half cells to test their electrochemical performance. Our results show the composite ceramic BSCF/LSCF possess higher electronic conductivity in the designed symmetric cells. The results of this investigation can be used in fabrication of fuel cells capable of operating in lower temperatures, which can reduce the overall costs of obtaining electricity and increase the performance efficiency.

Hadi Firoozi is a last year MSc student in Materials Science at Science and Research Branch at Islamic Azad University. His research experiences include surface characterization and modification materials as well as different methods of surface coating including chemical vapor deposition (CVD) and physical vapor deposition (PVD).

The geometry, structural properties and importantly surface features of implants play an important role on their biocompatibility and post implantation induced foreign body response. The formation of fibrotic tissue surrounding the implants can define their fate and potentially hinder the performance of medical devices by creating diffusional barriers for oxygen and nutrient transport. The reduced transport dynamics can then lead to creation of hypoxic conditions affecting tissue function and possibly resulting in necrosis and cell death. It is therefore crucial to study the surface features and characteristics of biomaterials prior to implantation. In this study, we investigate different surface geometries of multiple porous materials mostly used as outer surfaces of medical devices and biosensors. These materials include, porous medical grade stainless steel and pure titanium, porous sol gel ceramics, PTFE and hydrogels. Scanning electron microscopy (SEM) shows significant variability in the surface characteristic of all studied implant materials. We hypothesis that pore sizes, their shape and distribution affect the diffusional rates of transport and the induced foreign body response, and ultimately the function of the medical device. Our analysis matched with an extensive literature study on foreign body response caused by these materials used in different applications further confirms the importance of our investigation on selection of biomaterials and their surface features based on the medical device application.