Scientific Program

Conference Series Ltd invites all the participants across the globe to attend 5th International Conference and Expo on Ceramics and Composite Materials London, UK.

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Scientific Program Day 1
Scientific Program Day 2

Day 2 :

  • Ceramic Engineering | Ceramic Compounds: Ceramic Materials
Location: Armstrong
Speaker

Chair

Sergey Sokovnin

Institute of Electrophysics, Russia

Session Introduction

Charles Hetzel

Brookhaven National Laboratory, USA

Title: Ceramics in particle accelerators

Time : 10:45-11:05

Speaker
Biography:

Charles Hetzel has held the title of Lead Project Engineer for a design and manufacturing organization which produced automated industrial machinery prior to joining NSLS-II. Upon joining the NSLS-2 project he was responsible for the design, procurement and fabrication of the storage ring vacuum chambers including the integration of these chambers into the magnet-girder assemblies and final installation in the storage ring tunnel. He also managed the production of the rf shielded bellows for interconnecting the storage ring vacuum chambers as well as the photon absorbers which protect critical components. He took over as the Vacuum Group Leader at NSLS-2 in 2014 and continues to resource plan and schedule major installation efforts. Most recent efforts are focused on the design and development of a thin film coating system for ceramic vacuum chambers.

Abstract:

Ceramics help to solve several very challenging problems which are common in particle accelerators and x-ray science experiments. From providing electrical isolation and multipin vacuum feed throughs to magnetically transparent vacuum chambers, ceramics are the ideal material. In this presentation author will give an overview of some of the common uses of ceramics at NSLS-II as well as some of the more specialized ceramic vacuum chambers. Author will also go over some of the recent coating developments at Brookhaven which use DC magnetron sputtering to apply a thin layer of titanium to ceramic chambers. This film provides a conductive layer for the image currents generated by the stored particle beam while minimizing Eddy currents produced by the fast pulsing magnets required for beam injection.
 

D J Whitefield

University of the Witwatersrand, South Africa

Title: The use of 3D printing and gelation casting to fabricate complex ceramic parts

Time : 11:25-11:45

Biography:

D J Whitefield has worked in the manufacturing sector for the mining industry for 16 years. He was the Technical Manager responsible for plant and process improvement for BOART Longyear. He ran production for five years for BARAT Carbide optimizing process and streamlining the flow of materials through the plant in order to meet and improve quality standards and customer requirements. He was a Section Head at De Beers Research Laboratories responsible for research development of carbide diamond PCD drill bits for oil and gas drilling. Currently, he is a Senior Lecturer at The University of the Witwatersrand focusing on research in ceramics, 3D printing, tape casting, bio ceramics and tungsten carbide projects.

Abstract:

The question to be answered by this research is, can a complex shaped ceramic part be manufactured successfully by combining 3D (additive manufacturing) and gelation casting techniques? A 3D printed mold was produced using ABS (Acrylonitrile Butadiene Styrene) filament which formed the negative of the part to be cast. Different gelation systems were used and the solids loading of the alumina ceramic powder in the gel were varied to optimize the systems viscosity. The alumina mixed with the gelation system was cast into the ABS printed molds. The parts were removed by dissolving the ABS mold in acetone. The combination of solids loading and gelation system had a significant influence on the sintered porosity and density of the final parts. An impeller shape was cast in this manner and achieved a density of 99% with an associated hardness of 18GPa. From the successful combining of 3D printing and gelation of alumina ceramic prior to sintering, components were manufactured with properties similar to alumina parts produced by classical processing methods.

  • Electro-magnetic and Optical Ceramics and Devices | Surface Engineering and Ceramic Coatings | Alloys
Location: Armstrong
Speaker

Chair

Slawomir Kaczmarek

Westpomeranian University of Technology, Poland

Session Introduction

Slawomir M Kaczmarek

Westpomeranian University of Technology, Poland

Title: Influence of nitriding process on magnetic properties of steel ball-like samples

Time : 11:45-12:05

Speaker
Biography:

Slawomir M Kaczmarek has his expertise in evaluation and passion in materials science. He is a physicist by profession. For many years he was involved in optical and EPR spectroscopy of crystalline laser and scintillation materials produced by himself and other scientific centers in Poland, France and Japan. He mainly studied oxide materials such as garnets, lithium niobate, lithium tetraborate, melilites and fluorides doped with transition metals and rare earths. At the same time, he was a lecturer in physics, electronics and optoelectronics at the Military University of Technology in Warsaw and the West Pomeranian University in Szczecin. Recently, he became interested in the properties of powder materials, alloys, ceramics and nanomaterials, additionally conducting research on their magnetic properties using the SQUID technique. He is particularly interested in composite materials ranging from classic iron alloys to ceramic composites with nanoparticles.

Abstract:

The nitriding is a thermo-chemical treatment of the steel which improves its wear resistance, corrosion resistance and hardness. Gas nitriding is a thermo-chemical processing of steel implemented in the temperature range of 400-600ºC. The nitriding process takes place in conditions of forced flow of the nitriding atmosphere. At a constant temperature, depending on the value of the nitriding potential, the subsurface iron nitride layer formed may consist of only the γ'-Fe4N phase or a mixture of phases γ’-Fe4N and ε-Fe2–3N. A diffusion zone is formed under the iron nitride layer, in which nitrogen is dissolved interstitially in a ferritic matrix and carbonitrides of iron and alloying elements occur. The thickness and phase composition of the layers of iron nitrides are decisive on the resistance to corrosion and the abrasive wear of steel after nitriding. The diffusion zone, in the case of alloy steels, increases the fatigue strength of steel. The surface layer (core shell) appearing after nitriding treatment affects the magnetic and electric properties of the steel. Several AISI steel balls with different diameters and thermal treatments (Nx1021, Nx1025) were investigated using FMR and SQUID techniques. FMR spectra revealed wide and intense signals visible in temperature range from helium to room one. Position of each signal, being far from geff~2, as expected for iron magnetic ions, indicated on complex nature of responsible magnetic centers. Magnetization measurements have shown non-uniform behavior of the investigated samples with temperature variation. For most of them, having carbon content higher than 0.13 wt. %, the rise of magnetization with increasing temperature was observed, which strongly depended on applied magnetic field. For samples with carbon content lower than 0.13%, a drop in
magnetization was observed with increasing temperature, as usually for AISI steel. Significant magnetic anisotropy has been revealed, decreasing with increasing temperature.
The magnetization, M(T), dependence of the AISI_85-89 samples: a). AISI_420C (88) sample: precursor, Nx1021 and Nx1025 nitriding processes for H=100 Oe, b). AISI_420C (88) sample for H=10, 50 and 5000 Oe, c). hysteresis loops for AISI_1010 (85) (14 K) and the same sample underwent to Nx1025 process (20 and 230 K), hysteresis loops for AISI_420C (88) (15 K) and AISI_1085 (89): Nx1025 (10 K), and, e). M(T) dependence of AISI_1010 (85) and AISI_1010 (85) (Nx1025) samples for H=100, 300 and 500 Oe.

Anna Backerra

The Netherlands

Title: Four types of electrons, each allowing matter to behave in a specific way, according to twin physics

Time : 12:05-12:25

Speaker
Biography:

Anna Backerra has completed her Graduation in Theoretical Physics at the Eindhoven University of Technology in The Netherlands and worked for three years at Philips Research Laboratories. She has continued independently, making a search for complementary physics. To develop a way of complementary thinking she studied composition at the Conservatory in Enschede and in Saint Petersburg. After that she constructed a complementary mathematical language and applied this on physics, obtaining twin physics. The results are published in Physical Essays, Applied Physics Research and combined in a book.

Abstract:

Using the Heisenberg principle and the definition of complementarity as defined by Max Jammer, formalism is developed, based on the concept that determinate and indeterminate aspects of phenomena are mutually independent and that they occur joined in nature in such a manner that one of both dominates an observation and the other occurs as a small disturbance. Combining this starting point with relativity theory, space may be considered as a finite physical item, having an extremely low energy density and a potential equal to that of mass. The basic item in the theory is the Heisenberg-unit, defined as a constant amount of potential energy and supplied with complementary attributes of time, space and charge. Only by interaction with another Heisenberg unit, potential energy can be transformed into physical items. Space is described in a geometrical way. The resulting complementary language creates a bridge between large- and small-scale phenomena. A series of elementary particles as well as the four forces of nature, neutron decay and gravitational waves can be described; the laws of Maxwell emerge in an easy way. Moreover four distinct types of electrons have been found, having features being unknown in classical physics. For instance they may have an unexpected large distance to a belonging atom, or a short-range magnetic field around. The geometrical description of their spatial features seems to make these descriptions suitable to apply rather straightforward to experimental results.

Oloyede O R

Afe Babalola Univerity, Nigeria

Title: Improving wear performance of multi-layer electroless Ni-based coating using laser heat treatment

Time : 12:25-12:45

Speaker
Biography:

Oloyede O R is a dynamic scholar and research oriented fellow with track record of publications in notable international journals, who believes in solving industrial challenges through critical thinking. He is a specialist in Materials characterization, fabrication and corrosion control with excellent practical, teaching, and supervisory skills gathered over the years. He is a senior lecturer in the Mechanical Engineering Department, Afe Babalola Univerity, Nigeria. He is dedicated to academic excellence and his focus has being to remain a bridge and catalyst to lasting legacy in sound research and innovation in Materials & Mechanical Engineering worldwide! Dr. Oloyede, is an adaptable, resourceful and efficient researcher with excellent communication skills in the field of Advanced Materials. He is a consultant to Universities and firms in Nigeria, and he is constantly contributing to the world’s body of knowledge by adding values to engineering materials evolution, stability and better usage worldwide.

Abstract:

The industrial application of electroless nickel (EN) based plating in automobile, maritime and spacecraft parts manufacturing sector is growing by the day due to its high hardness, uniform thickness deposition as well as its excellent thermal, wear, impact and corrosion resistance. In this study, emphasis is on the formulation and deposition of multilayer duplex Ni-P/Ni-W-P coatings; as well as the observed microstructural and tribology behaviour changes between the as-deposited and laser treated coatings. The coatings were obtained from acidic electroless bath. The supersaturated as-deposited coats were observed to have been strengthened by precipitation of nickel phosphide crystallites as a result of controlled and suitable laser treatment. The morphological transformation was confirmed using optical and SEM while the observed change in mechanical property (increased wear resistance) was evaluated using pin-on-disc test apparatus. The results show the case of laser treated Ni-P/Ni-W-P duplex coatings offering better grain orientation/recrystallization, reduced porosity formation and improved wear resistance than in the asdeposited
coatings.

Osama M Ibrahim

Kuwait University, Kuwait

Title: Formation of aluminum-oxide layer on the surface of Fe-Cr-Al fibers

Time : 13:15-13:35

Speaker
Biography:

Osama M Ibrahim has completed his Graduation at the University of Wisconsin-Madison, USA with a PhD degree in Mechanical Engineering and minor in Chemical Engineering. He has held various teaching, research & development, and executive management positions at RYPOS, Inc., University of Rhode Island, and University of North Carolina-Charlotte. Currently, he is a visiting Associate Professor at University of Kuwait.

Abstract:

The objective of this paper is to investigate the formation and adhesion of a protective aluminum-oxide layer (alumina) on the surface of Iron-Chromium-Aluminum (Fe-Cr-Al) alloy. The oxide scale layer was developed via multi-stage thermal oxidation that consists of the following heating stages: at 930°C for one hour, at 960°C for 1 hour, and finally at 990°C for 2 hours for a total of 4 hours, which represents one heat treatment cycle. Thermogravimetric Analyses (TGA) was performed to quantify the development of the oxide layer. The first sample was tested for one cycle of 4hours; while the second sample was tested for 18 repeated cycles of 4 hours for a total of 72 hours. Both
samples gained weight due to oxidation.Scanning electron microscope (SEM) images show that one heat treatment cycle, results in the formation of predominantly alumina platelets like and whiskers. After 18 heat treatment cycles, however, the surface of the oxide scale layer becomes smoother and more uniform. Following vibration for1 hour consists of 50Hz for 30min, 100Hz for 15min, and finally at 150Hz for 15min and minimum handling of the two samples, peeling or spalling of the protective oxide layer was observed. Energy Dispersive spectroscopy (EDS) analysis of the heat-treated samples of Fe-Cr-Al sintered metal fibers confirmed the high aluminum content on the surface of the protective oxide layer and the low aluminum content on the exposed base metal alloy surface.
Figure : FeCrAl fiber heat treated for 72 hours

Oloyede O R

Afe Babalola Univerity, Nigeria

Title: Effect of heat treatment on the morphology and mechanical properties of commercial aluminium 6063 alloy

Time : 13:35-13:55

Speaker
Biography:

Oloyede O R is a dynamic scholar and research oriented fellow with track record of publications in notable international journals, who believes in solving industrial challenges through critical thinking. He is a specialist in Materials characterization, fabrication and corrosion control with excellent practical, teaching, and supervisory skills gathered over the years. He is a senior lecturer in the Mechanical Engineering Department, Afe Babalola Univerity, Nigeria. He is dedicated to academic excellence and his focus has being to remain a bridge and catalyst to lasting legacy in sound research and innovation in Materials & Mechanical Engineering worldwide! Dr. Oloyede, is an adaptable, resourceful and efficient researcher with excellent communication skills in the field of Advanced Materials. He is a consultant to Universities and firms in Nigeria, and he is constantly contributing to the world’s body of knowledge by adding values to engineering materials evolution, stability and better usage worldwide.

Abstract:

Commercial aluminium alloys are very versatile and second only to steels in use as structural engineering material. Meanwhile, heat treatment and alloying have been recognized as the major re-engineering procedures to obtain any desired specification. In this study, a clear case of the effect of post-production processing and its consequent microstructure and effectual changes in mechanical properties of a commercial Aluminum 6063 alloy is presented. The control sample is a normalized as-received aluminum alloy from Overseas Aluminum, India. It has been observed that at constant elemental composition; when this control sample was annealed at 260°C for 2 hours below its lower critical extrusion temperature of 413°C (775°F) and followed by regulated cooling at 10°C (50°F) per hour in a Muffler furnace, there was morphological
and property evolution. The samples were analyzed using Optical and Scanning Electron Microscopy with inbuilt EDX. The observed change in morphology prompted further analysis using XRD to confirm possible phase transition in the alloy at constant elemental composition as a result of noted change in grain refinement, more ductility and toughness in the annealed sample. From the results obtained, it can be said that mechanical properties depends largely upon the various form of heat treatment operations and cooling rate. Hence depending upon the properties and the applications that may be required for any design purpose, a suitable form of heat treatment normalizing, annealing or quenching should be adopted. For high ductile and minimum toughness, annealed aluminium 6063 will give satisfactory results.

  • Advanced Materials| Composite Materials
Location: Armstrong
Speaker

Chair

P N De Aza

Miguel Hernández University, Spain

Session Introduction

Kenji Uchino

The Pennsylvania State University, USA

Title: Piezoelectric composites

Time : 14:15-14:35

Speaker
Biography:

Kenji Uchino is the pioneer in “piezoelectric actuators”, is the Founding Director of International Center for Actuators and Transducers, Professor of EE and MatSE, and Distinguished Faculty of Schreyer Honors College at The Penn State University. He was the Founder and Senior Vice President of Micromechatronics Inc., State College, PA from 2004 till 2010, and Associate Director at Office of Naval Research-Global from 2010 till 2014. After his PhD degree from Tokyo Institute of Technology, Japan, he became Research Associate in 1976 at this university. Then, he joined Sophia University, Japan as an Associate Professor in 1985. He was recruited from The Penn State in 1991. He has authored 570 papers, 75 books and 31 patents in the ceramic actuator area. 48 papers/books have been cited more than 100 times, leading to his average h-index 70. He is the Fellow of American Ceramic Society and IEEE. He is currently the IEEE UFFC Distinguished Lecturer.

Abstract:

Piezo-composites composed of a piezoelectric ceramic and polymers are promising materials because of their excellent tailorable properties. The geometry for two-phase composites can be classified according to the connectivity of each phase (1, 2 or 3 dimensionally) into 10 structures; 0-0, 0-1, 0-2, 0-3, 1-1, 1-2, 1-3, 2-2, 2-3 and 3-3. In particular, a 1-3 piezo-composite, or PZT-rod / polymer-matrix composite is considered most useful. The advantages of this composite are high coupling factors, low acoustic impedance, good matching to water or human tissue, mechanical flexibility, broad bandwidth in combination with a low mechanical quality factor and the possibility of making undiced arrays by simply patterning the electrodes. The acoustic match to tissue or water (1.5 Mrayls) of the typical piezo-ceramics (20-30 Mrayls) is significantly improved when it is incorporated into such a composite structure, that is, by replacing some of the dense and stiff ceramic with a less dense, more pliant polymer. Piezoelectric composite materials are especially useful for underwater sonar and medical diagnostic ultrasonic transducer applications. In this presentation, other types of composites based on piezoelectric ceramics are also introduced. Piezoelectric energy harvesting devices comprised of ‘Cymbal’ have been applied for the engine vibration suppression and 1 W level energy harvesting in practice; while piezo-passive-dampers are comprised of a piezoelectric ceramic particle, polymer, and a carbon black, which suppress the noise vibration more effectively than traditional rubbers. Another type of composite with a magneto-strictive ceramic and a piezoelectric ceramic produces an intriguing product effect, the magnetoelectric effect in which an electric field is produced in the material in response to an applied magnetic field.

Nasrin Al Nasiri

Imperial College London, UK

Title: The oxidation behaviour of a melt infiltrated (MI) SiC/SiC matrix composite (CMC) at high temperature in air

Time : 14:35-14:55

Speaker
Biography:

Nasrin Al Nasiri has joined Imperial in December 2010 as a PhD student in the Department of Mechanical Engineering. Her PhD was about investigating the influence of microstructure of SiC materials on the mechanical behavior at room temperature. She was the first to quantify slow crack growth of SiC at ambient conditions. She has obtained her BSc and MSc degrees in Aerospace Engineering at Delft University of Technology, The Netherlands. After her PhD, she worked on the oxidation behavior of SiC ceramic matrix composites (CMCs) and designing new environmental barrier coatings. She has been awarded with the Imperial College Junior Research fellowship in November 2016 for a funding of three years. In September 2018, she has started her Royal Academy of Engineering Research Fellowship where she will be investigating the performance of ceramic composites and developing coating technologies for aerospace, energy and automotive sectors.

Abstract:

Ceramic matrix composites (CMC) have received significant attention from many researchers for being excellent candidates for gas turbine applications. Using CMCs led to a significant improvement in fuel consumption and thrust to weight ratio in comparison to metal based alloys. In addition, the low density of CMCs allows potential weight savings of up to 30% comparing to Ni-based super alloys. Si-based ceramics have excellent oxidation resistance due to the formation of a protective silica layer when it reacts with dry air, however their oxidation behaviour is not fully understood. Oxidation behaviour of silicon melt infiltrated SiC/SiC ceramic matrix composites (CMC) was studied in air up to 1400°C for 1, 5, 24 and 48 h in a furnace. Weight gain and oxide layer thickness measurements were performed to study the oxidation kinetics and how the oxidation temperature and time affect the oxidation kinetics of SiC/SiC composites. Different characterisation techniques were used to study the formation and the
nature of oxide layer (SiO2).

Vandana A Mooss

Savitribai Phule Pune University, India

Title: PANI-ZnO nanocomposites embedded polyurethane films for antifouling applications

Time : 15:30-15:45

Speaker
Biography:

Vandana A Mooss is presently doing her doctoral degree in Chemistry at the Department of Chemistry, SPPU, Pune, Maharashtra, India. Her area of research includes Polyaniline and its modified nanocomposites for anticorrosion, antifouling and supercapacitor applications.

Abstract:

Biofouling arising due to the nonspecific protein adsorption is a persistent challenge for any submerged surface and has a detrimental impact on the marine eco-system. The ensuing biocorrosion is accountable for an annual economic damage to the tune of ~ 500 billion USD. Additionally, it also affects adversely on the fuel efficiency by lowering of the cruising speed which eventually lead to the increased emission of greenhouse gases and unanticipated catastrophe related to structural failures. Hence, the eradication or prevention of biofouling process in the maritime/naval industries is highly relevant and offers a direct influence on economic, environmental or social factors. Commercially, strategies include the usage of biocides which is a major threat to the flora and fauna of marine eco-system. In the present work, a passive strategy is attempted specifically to inhibit the biofilm formation which is one of the crucial steps in the biofouling without possessing any bactericidal effect. Novel polyaniline- ZnO nanocomposites have been synthesized using an anti-nutrient natural chelating acid to render superior surface and mechanical properties. The antifouling property of the nanocomposite embedded polyurethane surfaces have been systematically investigated against marine bacteria, Vibrio harveyi (Gram negative) and Bacillus licheniformis (Gram positive) both qualitatively and quantitatively. The desirable properties of these nanocomposites could further envisage their utility in long-term maritime and naval applications.

  • Poster presentations
Location: Armstrong

Session Introduction

Charles Hetzel

Brookhaven National Laboratory, USA

Title: Ceramics in particle accelerators
Speaker
Biography:

Charles Hetzel has held the title of Lead Project Engineer for a design and manufacturing organization which produced automated industrial machinery prior to joining NSLS-II. Upon joining the NSLS-2 project he was responsible for the design, procurement and fabrication of the storage ring vacuum chambers including the integration of these chambers into the magnet-girder assemblies and final installation in the storage ring tunnel. He also managed the production of the rf shielded bellows for interconnecting the storage ring vacuum chambers as well as the photon absorbers which protect critical components. He took over as the Vacuum Group Leader at NSLS-2 in 2014 and continues to resource plan and schedule major installation efforts. Most recent efforts are focused on the design and development of a thin film coating system for ceramic vacuum chambers.

Abstract:

Ceramics help to solve several very challenging problems which are common in particle accelerators and x-ray science experiments. From providing electrical isolation and multipin vacuum feed throughs to magnetically transparent vacuum chambers, ceramics are the ideal material. In this presentation author will give an overview of some of the common uses of ceramics at NSLS-II as well as some of the more specialized ceramic vacuum chambers. Author will also go over some of the recent coating developments at Brookhaven which use DC magnetron sputtering to apply a thin layer of titanium to ceramic chambers. This film provides a conductive layer for the image currents generated by the stored particle beam while minimizing Eddy currents produced by the fast pulsing magnets required for beam injection.
 

Lewis J Print

University of Strathclyde, UK

Title: Using pre-ceramic polymers in the joining of silicon carbide ceramics
Biography:

Lewis J Print is pursuing his PhD in Polymer Chemistry at the University of Strathclyde. Under the supervision of Dr John J Liggat L. Print focuses on the development of methodologies to adhere silicon carbide ceramic using polymers for high temperature applications. This includes utilising a variety of analysis technique to characterise these polymers: including thermal analysis, thermal degradation and spectroscopy techniques. He also has interests in biodegradable polymers, the mechanical and physical properties of various polymers and novel applications of IR spectroscopy.

Abstract:

Organic-inorganic hybrid materials are becoming increasingly more useful in industry for combining polymers with ceramics. The resulting material offers a variety of characteristics of significant value to industry, including high mechanical strength and thermal resistivity. Using these hybrid materials, ceramics can adhere together effectively. Currently, an organic adhesive resin system is used to join silicon carbide (SiC) rods together. However, due to their toxicity there is a necessity to remove these from the application. Comparing the organic resins, as a joining agent, with pre-ceramic silicon based polymer resulted in a large difference in the quality of the joints produced from SiC rods. The rods mechanical strength and resistivity across the weld were compared as factors. A four-point flexural test and a four-point terminal resistivity test were used for this analysis. These polymer materials were analysed using Fourier-Transform infrared spectroscopy (FTIR) and Differential scanning calorimetry (DSC) to determine the curing reactions occurring in both systems. Thermogravimetric analysis (TGA) was also performed to determine polymer retention at 800°C. Additionally, these welds were compared under an optical microscope to investigate the difference in the integrity of the welds produced. X-ray powder diffraction (XPD) was also used to analyse the polymer: ceramic conversion undergone at high temperatures for the silicon based polymer.The new silicon polymer rods showed much better strength and resistance values compared to the organic resin joined rods. Their integrity and retention at high temperatures also showed improvements over the current system used. It can be determined from this that they can be successfully used in this system as a replacement for the organic organic resin. This makes the materials much safer and much more effective as a joining adhesive for the SiC rods.

Chen Barad

Ben-Gurion University, Israel

Title: Influence of galia (Ga2O3) addition on the phase evolution and grain growth behavior of voided yttria stabilized zirconia (YSZ) powder
Biography:

Chen Barad is pursuing her Graduation and has expertise in sol-gel synthesis and in the field of ceramic materials. Her previous knowledge and experience in chemistry and chemical engineering creates new pathways for research in the field of ceramic materials. She has experience in research of YSZ powders and other zirconia based powders for energy applications (solid oxide fuel cells and thermal barrier coatings), designing powder particle morphology and analyzing XRD patterns.

Abstract:

The effect of galia addition to diverse metal oxides has been occupying researchers in the aspects of preparation finer powders and improving sintering of advanced ceramic materials for high temperature applications. Pure galia shows polymorphism, but at high temperatures only its monoclinic form is thermodynamically stable. Moreover, by adjusting the ambient atmosphere, oxygen vacancies are formed in the non-stoichiometric gallium oxide structure which is advantageous in oxygen ion conducting applications. However, in spite of being the most popular solid oxygen conducting electrolyte, the addition of galia to YSZ has not been researched profoundly. The effect of a galia (Ga2O3) addition on the crystallographic phase transformations and the grain growth behavior of yttria stabilized zirconia (YSZ) were investigated regarding powders containing different amounts of galia in the range of 0-25 mol %. Ternary compositions of galia- YSZ sponge-like cryogels were prepared by the sol-gel method combining freeze-drying process and calcination of dried powders at different temperatures for two hours in air. Crystallographic phase transitions were analyzed via X-ray diffraction (XRD) and exceptional powder particle morphology of internal nano voids derived from the freeze-drying technique was investigated by using Scanning Transmission Electron Microscope (STEM). The effect of Ga2O3 addition to 8YSZ was found to be similar to that of Ga2O3 addition to zirconia sol-gel powders. The addition of Ga2O3 to 8YSZ inhibited the crystallization of 8YSZ extending the amorphous range and increasing activation energy for the growth process of grains. Regarding solgel powder morphology, it was found that by coupling the sol-gel synthesis with the freeze-drying technique it is achievable to preserve unique nano-voids in the ternary it is achievable to preserve unique nano-voids in the ternary system of 8YSZ+Ga2O3.