Titanium disulfide films were prepared by plasma CVD. Crystalline orientation of layered TiS2 was investigated in relation to deposition rate, film thickness, and kinds of substrate. The preferred orientation of TiS2 basal plane perpendicular to substrates was obtained on the films with their thickness of more than ca. 10 μm at the deposition rate of ca. 4 ⊠ 10−3 g/cm2·h on all kinds of substrate. This orientation resulted in a large discharge capacity in a lithium battery cathode application.

The role of particle and grain size on the dielectric behavior of the perovskite relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 [PMN] was investigated. Ultrafine powders of PMN were prepared using a reactive calcination process. Reactive calcination, the process by which morphological changes take place upon reaction of the component powders, produced particle agglomerates less than 0.5 μm. Through milling, these structures were readily broken down to ∼70 nanometer-sized particulates. The highly reactive powders allowed densification as low as 900 °C, but with corresponding grain growth in the micron range. Such grain growth was associated with liquid phase sintering as a result of PbO–Nb2O5 second phase(s) pyrochlore. Sintering, assisted by hot uniaxial pressing, below the temperature of liquid formation of 835 °C, allowed the fabrication of highly dense materials with a grain size less than 0.3 μm. The dielectric and related properties were determined for samples having grain sizes in the range of 0.3 μm to 6 μm. Characteristic of relaxors, frequency dependence (K and loss) and point of Tmax were found to be related to grain and/or particle size and secondarily to the processing conditions. Modeling of particle size/dielectric behavior was performed using various dielectric properties of 0–3 composites comprised of varying size powder in a polymer matrix. An intrinsic-microdomain perturbation concept was proposed to interpret observed scaling effects of the relaxor dielectric behavior in contrast to normally accepted extrinsic grain boundary models.

The relation between the oxygen adsorption and the voltage dependence of the resistor (VDR effect) in (Sr, Ca)TiO3−x based ceramics has been investigated. The nonlinearity of the voltage-current characteristics increased with increasing the barrier height, which is thought to be generated by the oxygen chemisorption. Acceptor type trap levels were detected by means of a zero biased DLTS technique at high temperatures. These interfacial energy levels changed with reoxidizing temperatures, and the change can be explained by the degradation of the chernisorbed oxygen. The high temperature type of the chemisorbed oxygen as O2− and O is relatively stable due to the strong pinning effect of trapped electrons, with reoxidizing anneals of grain surfaces above the oxidation temperature, and it contributes greatly to the VDR effect. It is concluded that energy barriers are caused by the interface states generated by the chemisorbed oxygen on grain surfaces and that they determine the VDR effect.

Aerosol droplets of a dilute aqueous solution of Ni(II) and Fe(III) nitrates were used to synthesize fine nickel ferrite powders by pyrolysis at temperatures ranging from 450 °C to 810 °C. The aerosol product was characterized by thermal analysis, x-ray diffraction, scanning electron microscopy, and BET surface area determination. At low temperature (480 °C), very active fine, hollow, noncrystalline spheres were formed. As the pyrolysis temperature increased, sintering occurred, larger particles with broader size distribution were obtained, and a higher degree of crystallinity of nickel ferrite was produced. The products at pyrolysis temperatures of 660 °C and above exhibited magnetic properties. The powders prepared from the aerosolization process at low temperatures had high reactivity and crystallized rapidly. The effect of the initial solution concentration was also studied, and dilute solutions produced spheres with fine size and narrow size distribution.

Precipitation of calcium carbonate from hydroxyethyl cellulose (HEC) containing aqueous solutions of CaCl2 and Na2CO3 resulted in an uncommon polymorph, vaterite. In contrast to precipitations without HEC, crystallization in the presence of HEC led to a shell-shaped body consisting of organized vaterite platelets. The artificial shell is a composite of stacks of vaterite and about 2% HEC. In the experimental arrangement used, HEC controlled both nucleation and crystal growth of vaterite. Concentration of HEC also affected the platelet's thickness which in turn influenced the shell's morphology as well. These results demonstrate the importance of organic-inorganic interface in controlling crystallization.

The single crystal growth of boron phosphide (BP) by employing the high pressure flux method and chemical vapor deposition (CVD) process is described together with characterization of the prepared BP and its electrical, thermal, semiconducting, and electrochemical properties. BP single crystals prepared by the high pressure flux method contain copper used as the flux, but they are promising for photocathode materials. BP single crystalline wafers prepared by the CVD process using Si wafer substrate contained autodoped silicon with the concentration of 1018−1020 atoms·cm−3, depending on the growth temperature and the substrate plane. The Si atoms which act as acceptors are incorporated at phosphorus sites in BP. The lattice constants determined by the Bond method explain the conduction type of BP. Some electronic transport properties such as donor and acceptor levels and lattice scattering process before and after thermal neutron experiments are clarified. The thermal conduction is limited by three-phonon processes. The formation of defects by thermal neutron irradiation and that of structural disorder by ion-irradiation are mentioned. Schottky diodes consisting of n–BP and Sb or n–BP and Au, which are denoted as n–BP–Sb and –Au, respectively, show excellent characteristics, and their barrier heights are independent of metals and two-thirds of energy bandgap, expected from the surface-state model. Finally, recent results on thermoelectric properties of sintered specimens are mentioned.