Composite solid oxide

Composite solid oxide/molten carbonate electrolyte membrane... 

Y. X. Zhang, C. R. Xia, and M. Ni, Int. J. Hydrogen Energ., 37, 3392 (2012). Simulation of Sintering Kinetics and Microstructure Evolution of Composite Solid Oxide Fuel Cells Electrodes. 

A Small but important daSS of fOi mUlatiOnS comprises the Composite Solid Rocket Propellants. Composites typically contain a major amount of an oxidizer such as AP or HMX, a metal powder such as Al, a binder which is one or another type of rubber (or double-base), and up to a dozen trace ingredients such as catalysts, stabilizers, etc. There are literally hundreds of formulations, all to a degree similar and the choice comes down to specific missions, economics, and special requirements Loading of End Items. The blends and formulations described above may be loaded into their hardware in the plant where they are made, or they may be shipped to another plant for Load/... 

Hydrazinium diperchlorate (HP2) is one of the higher energetic oxidizers considered for use in composite solid propints with hydrocarbon binders. Its other advantages include high density, high burning rate, and moderate projected cost. Its shortcomings include relatively poor stability to vibrational and thermal shock... 

Price (Ref 39) compares the three principal quantitative models of ignition and concludes that there are serious deficiencies in the existing models, so much so that no one theory appears adequate to represent the complexity of ignition of composite solid proplnts. In the gas-phase model (Refs 22 36) the hot oxidizing environ-... 

The second major component of a composite solid propellant is the organic polymer material, which serves to bind the oxidizer and other... 

The basic approach taken in the analytical studies of composite-propellant combustion represents a modification of the studies of double-base propellants. For composite propellants, it has been assumed that the solid fuel and solid oxidizer decompose at the solid surface to yield gaseous fuel and oxidizing species. These gaseous species then intermix and react in the gas phase to yield the final products of combustion and to establish the flame temperature. Part of the gas-phase heat release is then transferred back to the solid phase to sustain the decomposition processes. The temperature profile is assumed to be similar to the situation associated with double-base combustion, and, in this sense, combustion is identical in the two different types of propellants. 

During the course of the last century, it was realized that many properties of solids are controlled not so much by the chemical composition or the chemical bonds linking the constituent atoms in the crystal but by faults or defects in the structure. Over the course of time the subject has, if anything, increased in importance. Indeed, there is no aspect of the physics and chemistry of solids that is not decisively influenced by the defects that occur in the material under consideration. The whole of the modem silicon-based computer industry is founded upon the introduction of precise amounts of specific impurities into extremely pure crystals. Solid-state lasers function because of the activity of impurity atoms. Battery science, solid oxide fuel cells, hydrogen storage, displays, all rest upon an understanding of defects in the solid matrix. 

Mai A, HaanappelVAC, UhlenbruckS, TietzF, and Stover D. Ferrite-based perovskites as cathode materials for anode-supported solid oxide fuel cells, Part I. Variation of composition. Solid State Ionics 2006 176 1341-1350. 

Zhou X, Deng F, Zhu M, Meng G, and Liu X. Novel composite interconnecting ceramics LaojCao jCrOj j/ Cc02Sm08O 9 for solid oxide fuel cells. Mater. Res. Bull. 2007 42 1582-1588. 

R.N. Singh, High Temperature Seals for Solid Oxide Fuel Cells, 28th International Conference on Advanced Ceramics and Composites, eds., E. Lara-Curzio and M.J. Readey, Cocoa Beach, FL, 25 (3), pp. 299-307 (2004). 

M. Bram et al., Basic investigations on metallic and composite gaskets for an application in SOFC stacks, in Proceedings of the Fifth European Solid Oxide Fuel Cell Forum, J. Huijsmans (ed.), 1-5 July 2002, Lucerne, Switzerland, 2202, pp. 847-854. 

Similarly, in the development of solid oxide fuel cells (SOFCs), it is well recognized that the microstructures of the component layers of the fuel cells have a tremendous influence on the properties of the components and on the performance of the fuel cells, beyond the influence of the component material compositions alone. For example, large electrochemically active surface areas are required to obtain a high performance from fuel cell electrodes, while a dense, defect-free electrolyte layer is needed to achieve high efficiency of fuel utilization and to prevent crossover and combustion of fuel. 

Lu XC and Zhu JH. Ni-Fe + SDC composite as anode material for intermediate temperature solid oxide fuel cell. J. Power Sources 2007 165 678-684. 

Zhou W, Shao Z, Ran R, Zeng P, Gu H, Jin W et al. Ba05Sr0 5Co0 8Fe02O3 5 + LaCo03 composite cathode for Sm0 2Ce0 80,9-electrolyte based intermediate-temperature solid-oxide fuel cells. J. Power Sources 2007 168 330-337. 

Nitric oxide has a very low ionization potential and could ionize at flame temperatures. For a normal composite solid propellant containing C—H—O—N—Cl—Al, many more products would have to be considered. In fact if one lists all the possible number of products for this system, the solution to the problem becomes more difficult, requiring the use of advanced computers and codes for exact results. However, knowledge of thermodynamic equilibrium constants and kinetics allows one to eliminate many possible product species. Although the computer codes listed in Appendix I essentially make it unnecessary to eliminate any product species, the following discussion gives one the opportunity to estimate which products can be important without running any computer code. 

K. Yamazaki K. Kishi, Composite Solid Propellant Containing Preshaped Oxidizer Salt-Metallic Fuel-Burning Rate Controller Particles , USP 3454437 (1969) CA71, 161... 

Another substantial increase in delivered energy was obtained by incorporating substantial amounts of solid oxidizer e.g., ammonium perchlorate) and metallic fuel e.g., aluminum) in the casting powder. The resulting family of composite-modified double-base (CMDB) propellants has found widespread use in ballistic missiles and space motors. 

In a nutshell, ADN appears to be an efficient oxidizer for the high performance eco-friendly propellants and is now envisaged as a suitable and better successor to AP. The use of ADN in composite solid propellants eliminates the emission of chlorinated exhaust products from rocket motors and gives 5-10 s more Isp than conventional AP-based propellants. 

According to this theory the rate-controlling reactions are associated with the gasification (pyrolysis) of the solid oxidant and the solid binder which in a composite propellant are essentially independent of each other. 

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