RISE Research Institutes of Sweden is a group of research and technology organisations. RISE is a leading innovation partner working global cooperation with academia, enterprise and society to create value, growth and competitiveness through research excellence and innovation.

In the area of Energy, RISE has developed innovation Roadmaps covering:

• Energy Efficient Transport
• Electric Power System
• Energy Efficient and Smart Buildings
• Sustainable Thermal Processes
• Efficient Energy Use in Industry
• Decarbonisation of Basic Industries

These Roadmaps describe development pathways for technologies, non-technical elements (market design, user behaviours, policies, etc.) and key actors that deliver on a plausible, desirable vision for each respective innovation area in 2030. These Roadmaps are intended to support RISE’s strategic planning and development, but should be relevant reading for anyone interested in energy innovation in Sweden.

Solid Oxide Fuel Cells (SOFC) are typically produced using organic solvent tape casting of one layer (electrolyte, anode or cathode) followed by deposition of the other layers by complex methods such as physical vapour deposition. Our aim is instead to use aqueous tape casting, followed by co-sintering. These are less costly processes, which causes less CO2-emissions, but co-sintering is a critical step. Both shrinkage and thermal expansion must be matched, and of course also the sintering temperature. Using water-based tape casting we have demonstrated co-sintering of NiO/YSZ-anode with 30% porosity and dense YSZ-electrolyte, in planar and tubular shapes. We have also shown that tape casting is a suitable prototype method for tubes. On-going work aims at increasing the porosity and decreasing the working temperature of the cell.

Ceramic tapes are traditionally produced by tape casting using organic solvents. The use of organic solvents has been questioned due to health, environmental and fire hazard risks. The use of water-based tape casting can reduce these problems. This study contains an environmental assessment of ceramic tapes in a life cycle perspective. Two tape casting techniques, using different solvents during the tape casting, are analyzed from cradle to grave, ie, from raw material production, manufacturing, application and recycling. The functional unit was defined as tape with 1000 gram of alumina content. Tape casting with water based solvent was compared to tape casting with hydrocarbon based solvent. In principal, only differing processes were examined. There are also quality issues associated with water based tape casting: the drying is slower and can cause cracking, air bubbles can be entrapped, and in some cases there can be problems with wetting. These problems can be handled by controlling the colloidal and rheological properties and using a system with high solids loading. In conclusion the results show that water based tape casting gives tapes of high quality and that a lower environmental impact is possible compared to solvent based tape casting. It is further shown that the sintering of the green tape, which follows the tape casting, is probably the process with most climate impact in the life cycle of a ceramic tape.

Alumina/silicon carbide composites have been fabricated by a new technique involving the in situ synthesis of nano-sized SiC particles. A mixture of alumina powder and silicon carbide precursors was prepared in an aqueous suspension. Green bodies were formed by cold isostatic pressing of granules obtained by freeze granulation, and pressureless sintered at 1750 °C for 4 h in an argon atmosphere. Mullite (10-20 vol%) formed in addition to SiC during sintering. The SiC particles were located predominantly to the interior of the mullite and alumina matrix grains. © 2008 Elsevier Ltd and Techna Group S.r.l.

The microstructures of as-sintered and creep tested polycrystalline mullite and mullite reinforced with 5 vol.% nano-sized SiC particles have been characterized by scanning and transmission electron microscopy. The dislocation densities after tensile creep testing at 1300 and 1400 °C were virtually unchanged as compared to the as-sintered materials which indicates diffusion-controlled deformation. Mullite matrix grain boundaries bending around intergranular SiC particles suggest that grain boundary pinning, in addition to a reduced mullite grain size, contributed to the increased creep resistance of the mullite/5 vol.% SiC nanocomposite. Both materials showed pronounced cavitation at multi-grain junctions after creep testing at 1400 °C which suggests that unaccommodated grain boundary sliding, facilitated by softening of the intergranular glass, occurred at this temperature. This is consistent with the higher stress exponents at 1400 °C. © 2008 Elsevier Ltd. All rights reserved.

Solvent mixtures of water and ethanol and water and isopropanol have been evaluated for processing of concentrated alumina suspensions. The addition of alcohols may increase the long-term stability of suspensions with soluble ceramic species such as magnesia, which is added as a sintering aid. A poly(acrylic acid) and a hydrophilic comb copolymer were used as dispersants for the different solvent mixtures. The aim was to compare the stabilization efficiency at normal processing conditions, pH 9-10, through rheological measurements and to develop a robust system including magnesia with long-term stability. The electrostatic stabilization of the dispersants in the different solvent mixtures was studied by zeta potential measurements. Highly negative zeta potentials were observed for the poly(acrylic acid) at pH 9-10 in the solvent mixtures. A charge contribution was also seen from the adsorbed comb copolymer, however smaller than for the poly(acrylic acid). Low viscosity was obtained for suspensions stabilized with poly(acrylic acid) in solvent mixtures with either 25 vol% ethanol or isopropanol. Higher alcohol to water ratio led to flocculation of the suspension when poly(acrylic acid) was used as dispersant. Alumina suspensions with added magnesia in isopropanol:water 25:75 and poly(acrylic acid) as dispersant showed long-term stability. The viscosity remained almost constant during 4 days of aging. Suspensions stabilized with the comb copolymer dispersant gave stable systems with ethanol and isopropanol concentrations between 25 and 75 vol%. The superior dispersing efficiency of the comb copolymer at alcohol contents above 25 vol% was believed to originate from steric stabilization in combination with low effective particle size, giving low viscosity through lower apparent solid contents of the suspension. © 2008 Elsevier Ltd. All rights reserved.