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Electrofluorination of benzoyl chloride-ring-UL-14C produced an isomer mixture of cyclic C6F11 carbonyl fluorides, principally 1,2,2,3,3,4,4,5,5,6,6-undecafluorocyclohexane-ring-UL14C carbonyl fluoride, which was derivatized with 2-bromo-4-nitroaniline and triethyl amine. The resultant carboxanilide mixture is designated as EL-499 labeled with 14C in the perfluoro alkyl ring for use in metabolic studies.

Using a tracer sectioning technique, the self-diffusion of Er in pure and HfO2-doped polycrystalline Er2O3 was measured at 1614° to 1900°C. Up to ≊ 10 mol% HfO2 dopant level, the Er self-diffusion coefficients followed a relation based on cation vacancies as the principal mobile defects present and available for cation diffusion. Above 10 mol% HfO2, deviation from this relation occurred, apparently due to clustering of cation vacancies and oxygen interstitials around the dopant hafnium ions. The activation energy for the self-diffusion of Er in pure Er2O3 was 82.2 kcal/mol and increased with the HfO2 dopant level present.

Tracer self-diffusion coefficients for Ca and Y were measured in pure and YF3-doped CaF2 crystals for dopant levels ranging from 2 to 10 mol% and temperatures between 960° and 1212°C. Coefficients for both cations increased approximately linearly with the square of the dopant concentration at constant temperature, with D*Ca>D*Y in doped crystals but D*Ca>D*Y in pure crystals. The activation energies for diffusion of both cations decreased with increasing dopant concentration. Atomic jump pathways are considered and the decrease in activation energy is explained in terms of reduction in the enthalpy of motion accompanying the formation of Willis anion defect clusters in the more heavily doped crystals.

An electron microprobe interdiffusion study was made in single crystals between 1200° and 1331°C over the solid-solution compositional range 0 to 20 mol% YF3 in CaF2. At constant temperature, the value of δ, the interdiffusion coefficient, increased approximately exponentially with increasing YF3 content. As YF3 content increased, the temperature dependence of δ decreased. Extrapolation of δ to 0% YF3 combined with consideration of the defect formation mechanism at mite dilution allowed estimation of the impurity diffusion coefficient for Y in essentially pure CaF2.

The dry abradability and diamond pyramid hardness of HfO2 fully-stabilized by variable additions of Er2O3 were determined on sintered polycrystalline specimens of near-theoretical densities. Measurements on fused silica and on a single crystal of Y2O3-stabilized ZrO2 were included for comparison. In general, the hardness was decreased and the abradability was increased by increasing additions of stabilizing oxide. These effects were attributed mainly to the increase in defect concentration of the anion sublattice with increasing amounts of modifier oxide. Solution of HfO2 in Er2O3 (rare-earth-oxide Type C structure) increased hardness and decreased abradability: effects which also seemed to be related to the defect concentration of the anion sublattice.

Hafnium diffusion was measured in polycrystalline Er2O3 with two impurity levels. A tracer sectioning technique was used and the diffusion coefficients were measured at 1601° to 1970°C. Volume diffusion of Hf showed both extrinsic and intrinsic behavior, with the transition temperature increasing with the impurity level present in Er2O3. The grain boundary diffusion was apparently extrinsic over the entire temperature interval.

The electrical properties of fluorite-structure solid solutions of HfO/sub 2/ fully stabilized by doping with Er/sub 2/O/sub 3/ were studied. The dependence of the total ac electrical conductivity and ionic transference number upon composition (10-50 mole percent (m/o) Er/sub 2/O/sub 3/), temperature (520/sup 0/-1070/sup 0/C), and oxygen partial pressure (1-10/sup -19/ atm) were investigated. Bulk electrical conductivities of polycrystalline specimens were separated from other polarizations by a complex impedance technique and were compared to conductivities of single crystals. The electrical conductivity generall decreased as the dopant level increased, although plateaus indicative of possible defect ordering were observed ove the composition range of 20-35 m/o Er/sub 2/O/sub 3/. The effects of surface finish, aspect ratio, and porosity of the specimens were negligible. All Er/sub 2/O/sub 3/ stabilized HfO/sub 2/ compositions were shown to be electrolytic conductors below 1070/sup 0/C for oxygen partial pressures less than 1 atm. Oxygen diffusion coefficients were calculated using the Nernst-Einstein equation.

Tracer self-diffusion coefficients for Er and Hf were measured in polycrystalline Er2O3-stabilized HfO2 (fluorite phase) at compositions between 10 and 40 mol% Er2O3 and temperatures between 1700° and 2033°C. In some instances, grain-boundary coefficients were also determined. The Hf volume coefficients were generally slightly smaller than Er coefficients, but neither showed a strong composition dependence, a finding most likely attributable to extensive clustering of charged defects which apparently rendered a large proportion of the “notional” defects essentially immobile. The activation energies for volume coefficients were very large, ranging from 630 to 760 kJ-mol−1, and generally decreased with increasing Er2O3 content.

A tracer sectioning technique was used to measure cation self-diffusion coefficients in fully dense polycrystalline YaO3 and Er2Os under oxidizing conditions. The results are described by the relations for Y2O3 (1400° to 1670°C), and for Er2O3 (1400° to 1700°C). The greater activation energy for erbium diffusion in erbia may be partly attributable to a mass effect.

The diffusion of oxygen in monocrystalline ScaO3, YzO3, Dy,O2, HosO3, Er2O3, Tm2O2, and Lu2O3 was measured by a thermobalance technique. The reoxidation of partially reduced crystals of these materials was treated as a diffusion-controlled process with a moving boundary. Large diffusion coefficients and fairly low activation energies were found for this process, in agreement with a proposed migration mechanism which involves the inherently defective anion sublattice of these materials.

Studies of the oxidation of Gd and Dy at PO2's from 10−0.3 to 10−14.5 atm and temperatures from 727° to 1327°C indicate both semiconducting and ionic-conducting domains in the sesquioxides formed. At higher temperatures, where dense coarsegrained oxide layers developed, the rate of oxidation in the high-P02 semiconducting domain yielded oxygen diffusion coefficients in Dy2O3 in excellent agreement with literature values derived from oxidation of partially reduced oxide single crystals. Under the same conditions, the oxidation of Gd yielded oxygen diffusion coefficients in cubic Gd2O3 which are considerably below literature values for monoclinic single-crystal Gd2O3. At lower temperatures, porous scales were formed, and apparent diffusion coefficients derived from oxidation rates show a smaller temperature dependence than the high-temperature data. At low PO2, the oxides behave as ionic conductors, and metal oxidation rates result in estimates of the electronic contribution to the electrical conductivity of the order of 10−6 to 10−7Ω−1 cm−1.

A microprobe study of interdiffusion between 1033° and 1238°C in the system SrF2-BaF2 was conducted using single crystals. The interdiffusion coefficient, D, generally decreased with increasing SrF2 concentration, but the composition dependence of D decreased with decreasing temperature. Extrapolation of D values to infinite dilution allowed the impurity cation self- diffusion coefficients: The values for DSr in BaF2 are in excellent agreement with tracer results. An analysis of the activation energies for cations diffusing in alkaline-earth fluorides shows a direct correlation between constriction ratio and migration energy for a single ion diffusing in different fluorides. An apparent anomaly arises when attempting to correlate migration energy with structural information for different cations diffusing in the same fluoride.

The uptake, translocation, and metabolism of the herbicide fluridone 1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone was studied in cotton (Gossypium hirsutum L. ‘Stoneville 213’) (fluridone tolerant) and corn (Zea mays L. ‘Migro 5040’), soybean [Glycine max (L.) Merr. ‘Calland’], and rice (Oryza sativa L. ‘Nato’) (fluridone susceptible). Uptake studies with 14C fluridone demonstrated that all species absorbed radioactivity with rice having the highest concentration. Equivalent concentrations of radioactivity were observed in corn, cotton, and soybean. Absorbed fluridone was retained primarily in the roots and the basal region of the stem of cotton, while in the herbicide susceptible species fluridone was readily translocated into the shoots. No appreciable metabolism of fluridone was observed in the roots or shoots of cotton and soybean. Tolerance of cotton to fluridone was primarily attributed to the limited translocation of the compound.

Interdiffusion coefficients were determined in single-crystal (Ca,Sr)F2 solid solutions in the temperature range 1100° to 1320°C. The composition dependence of the coefficients passes through a maximum that shifts toward higher CaF2 concentrations at higher temperatures. Extrapolation of the interdiffusion coefficient to extremes of composition provides impurity diffusion coefficients that agree well with tracer results. The changes in activation energy with composition can be explained readily on the basis of cationic radii and lattice parameters.

The self-diffusion of Ca in single-crystal CaF2 was determined by a tracer serial-sectioning technique. From 987° to 1246°C, the results can be described by Analyzing these results on the basis of a Ca ion vacancy diffusion mechanism, the enthalpy of migration, hm, can be estimated as 1.75 eV. The order of magnitude of the preexponential factor can be satisfactorily explained on the basis of lattice strain entropy effects.

Specimens of highly sinterable Gd/sub 2/O/sub 3/ powders were compacted and sintered. Two groups of specimens with grain sizes averaging 138 and 342 ..mu..m were produced. Contributions of lattice (or volume) and grain-boundary diffusion were determined. Oxygen diffusion in Gd/sub 2/O/sub 3/ was determined and compared with oxygen diffusion in Er/sub 2/O/sub 3/. (FS)