Research leading to the construction of an ambient temperature rechargeable magnesium battery based on organic electrolytes and positive electrodes capable of reversible intercalation of Mg § ions is discussed. The number of combinations of solvent, solute, and intercalation cathode which give reasonable battery performance is much more limited for Mg than for alkali metals. The only electrolytes which allowed Mg dissolution and deposition were solutions of organomagnesium compounds in ethers or tertiary amines; many of these were unstable in the presence of transition metal oxides or sulfides which were found to function acceptably as intercalation electrodes. Possible directions for future research which could solve these problems are discussed, as well as theoretical aspects of magnesium compound behavior in nonaqueous solvents.

ChemInform Abstract Various solvents, Mg compounds, and host materials for Mg intercalation (transition metal oxides, sulfides, and borides) are studied in order to develop an ambient temp. rechargeable magnesium battery based on organic electrolytes and cathodes capable of reversible Mg intercalation. The only electrolytes which allow Mg dissolution and deposition are solutions of organomagnesium compounds in ethers or tertiary amines. However, many of these solutions are unstable in the presence of transition metal oxides or sulfides, which are found to function acceptably as intercalation electrodes. Possible directions for future research which could lead to an improvement of battery performance are discussed.

Aqueous precipitation in a computer-controlled continuous crystallizer has been applied to the preparation of cordierite, mullite, alumina, and zirconia precursor powders. The particles are dense, spherical, and x-ray amorphous. The powders have a particle size range of 0.2–5 μm and a surface area of 1 – 10 m2/g The properties of the powders and of some green and fired pieces are described.

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A1 2 03–15 vol. % ZrO2 bar shaped composite specimens were fabricated by pressing three layers. The two outer layers consisted of Al2O3 and unstabilized ZrO2 (primarily in the monoclinic polymorph), and the inner layer consisted of Al2O3 and partially stabilized zirconia in the tetragonal polymorph. The transformation of ZrO2 from tetragonal to monoclinic, upon cooling from sintering temperature, led to the establishment of residual compressive stresses in the outer layers. Flexural tests at room temperature showed that residual stresses contributed to strength increasing from 450 to 825 MPa. The existence of these stresses was verified by measuring apparent fracture toughness, as well as using strain gages. Strength and toughness data were obtained at 500, 750, and 1000°C. X-ray diffraction was used to explain the elevated temperature data by monitoring the monoclinic to tetragonal transformation upon heating to 1000°C.