Fine grain, transformation-toughened Al2O3/ZrO2 (tetragonal, 5–30 vol. %) composites can exhibit both large deformation strains (80%) and strain rates (> 0.001 s−1) without tearing, cavitating, or cracking during hot forging at 1500 °C. Deformability increases with ZrO2 content. The Al2O3 grains grow, develop a crystallographic orientation, and form column structures with increasing deformation. The deformation behavior of the composite series primarily depends on the content of the ZrO2 phase. In this regard, two deformation regimes were observed that appear to be separated by the volume fraction where the ZrO2 phase might form a connective network.

Electrical conductivity and thermoelectric power have been measured for a series of MnZn ferrites as functions of the oxygen partial pressure under high-temperature equilibrium conditions. The isothermal variation of both properties was successfully correlated to the onset of phase transitions at characteristic Po2's. The ferrite 0.482MnO-0.518Fe2O3 was examined in some detail to locate the stability fields of the metallic alloy of iron and manganese, manganowustite, the spinel ferrite, and the hematitelike phase, and to extract the appropriate free-energy data. The results confirmed by x-ray diffraction are in satisfactory agreement with literature data.

LiNbO3 powders have been prepared by appropriate hydrolysis of lithium and niobium alkoxides using a sol-gel process. Ceramics with pretty high shrinkage coefficients and compactness have been obtained by sintering of the particles at 1075 °C.

The pH of the solution in contact with a hydrous zirconium oxide plays a dominant role in determining the crystal phase, tetragonal or monoclinic, in the calcined material. The substitution of low concentrations of hafnium for zirconium destabilizes the tetragonal phase so that only the monoclinic phase is formed; the amount of Hf required for destabilization depends upon the pH used for the preparation of the hydrous oxide. While this study has defined a phenomenon, the results do not permit a definition of the mechanism for it.

High-resolution nuclear magnetic resonance (NMR) spectra and synchrotron x-ray powder diffraction data have been obtained from a well-crystallized highly dealuminated sample of the zeolite ZSM-11. The Rietveld profile technique has been applied to the synchrotron data to give the first detailed refinement of the idealized structure derived ten years ago by distance least-squares modeling methods [G. T. Kokotailo, P. Chu, S. L. Lawton, and W. M. Meier, Nature 275, 119 (1978)], which involves 54 variable atomic positional parameters. The structure is tetragonal (a = 20.065 Å, c = 13.408 Å at 25 °C) and consistent with the previously reported tetragonal space group I \overline 4 m2, but the NMR spectra indicate local deviations from this symmetry that disappear at 100 °C.

The specific heat of liquid and solid phases and the heats of crystallization and fusion have been measured by differential scanning calorimetry (DSC) for a series of Te80Ge20 − x Pbx alloys (0≤x≤20). The enthalpy, entropy, and free energy of the undercooled liquid are quantitatively assessed with reference to the crystal phases. The available formulas for computing the free energy of the liquid are compared, and their relative merits are discussed. The glass transition temperature is shown to depend strongly on the ratio of the average excess specific heat of the liquid to the entropy of fusion. An anomaly in the liquid specific heat, which is particularly important for Te80Ge20 and Te80Ge15Pb5, leads to very good glass forming ability for these alloys; this is demonstrated by preparing amorphous samples by means of fluxing.

The effects of gamma irradiation on groundwater and the reaction between groundwater and glass have been investigated at radiation exposure rates of 2 × 105 1 × 103 and 0 R/h. These experiments, which bound the conditions that may occur in a high-level nuclear waste repository located in tuff, have been performed using the actinide-containing glasses ATM-lc and ATM-8, and have been performed for time periods up to 278 days. The experimental results indicate that when only the repository groundwater is present, the pH of the system remains near-neutral, regardless of the radiation field, due to the buffering capacity of the solution. When glass is added to the system, the subsequent reaction is governed by the solution chemistry, which results from a complex interaction between radiolysis products, glass reaction products, and groundwater components. While no long-term reaction trends have been extracted from the current data, it is noted that there are no outstanding differences in the reaction of the glasses as measured by the release of the soluble components B, Mo, and Na, as a function of radiation exposure rate. However, there is a marked difference in the amount of U, Np, and Pu released from the glasses as a function of radiation exposure rate. This difference can be correlated with the pH values of the leachate, with more basic solutions resulting in lower actinide release.