Indium tin oxide (ITO) conductive films were prepared on glass substrates by thermal decomposition of organometallic solution. The solution consists of a homogeneously dissolved indium/tin nitrile acetylacetonate and acetone. The solution was coated on a glass substrate, and then decomposed to yield a thin adherent film of ITO at temperatures ranging between 350°-600°C in air.
Various properties of the films were measured: etching rate of the films by HCl solution, mechanical strength, chemical stability, electrical resistivity, carrier concentration and mobility of the films. The films containing 5-15wt% of SnO₂ prepared by thermal decomposition at temperatures above 500°C were found to have a large etching rate, excellent resistance against rubbing with a rubber and stability in NaOH solution. Carrier concentration and mobility of the films increased with the heating temperature. Carrier concentration increased and mobility decreased with the increase of the content of SnO₂ in the film. The electrical resistivity of the films had a minimum value of 1.3×10^-3ohm⋅cm at the 5wt% of SnO₂ content. Carrier concentration and mobility of the film was typically 1.3×10²⁰cm^-3 and 35cm²⋅V^-1⋅s^-1 at room temperature, respectively.

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The glass samples having the composition of K_1-2nPb_nMg₃AlSi₃O₁₀F₂ (n=0.1-0.5) were prepared by melting of PbO, SiO₂, MgO, MgF₂, K₂SiF₆ and K₂CO₃ at 1350°-1450°C. Clear and cloudy glasses were obtained from the melts with composition of n>0.3 and of n<0.2, respectively. The crystallization of mica from the glasses at 600°-1100°C was investigated by use of DTA, electron microscopy and X-ray diffraction techniques. In the DTA curves, exothermic peaks due to crystallization of mica phase appeared at about 700°C, and shifted towards slightly higher temperature as the n value increased. From the changes in X-ray diffraction intensity of mica with annealing temperature and time, it is deduced that the growth rate of mica crystals in the direction of c-axis is lower than that in the other directions. Lattice constants of mica crystallized from the glasses with composition of Pb_0.5Mg₃AlSi₃O₁₀F₂ were as follows:
a=5.31₃Å, b=9.18₄Å, c=9.95₁Å, β=101°20′
The c was remarkably decreased with an increase in the n value.

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In order to study strength characteristics at room temperature and the strength evaluating-method of ceramic materials, bending-tests of bars, tensile tests of rectangular plates and spin-tests of centrally holed disks were conducted on hot-pressed silicon nitride (Si₃N₄) specimens. The relationship between the mean strength and effective volume of specimens was examined using Weibull's theory; and also, observations of the fracture origin and of the crack propagation on the fracture surfaces were made.
The results obtained were as follows;
The values of mean strengths obtained from the tensile tests and the spin-tests, agreed well with those predicted from the results of the bending-tests of the material. Good test-results were obtained without showing any eccentric load effect in the present tensile test, where the specimens received the loads through cross-pin connectors at both ends of the test-pieces to which steel attachments were fixed with adhesive. Locations of the fracture origins did not necessarily coincide with the site where the maximum stress was predicted to occur, and the discrepancies between the actual and predicted sites were generally large when stress-gradients on the fracture surface were small.

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The structure of 2B₂O₃⋅Na₂O glass has been investigated by the radial distribution function based on X-ray scattered intensity data. Peaks in the correlation curve were observed at r=1.45, 2.40, 3.70, 4.25, 4.60, 5.9 and 6.3Å. Each boron atom was surrounded by 3.4 oxygen atoms on the average at a distance of 1.45Å. A quasi crystalline structure model after 2B₂O₃⋅Li₂O of which framework was constructed by diborate groups gave a good agreement between the calculated and observed intensity curves S·i(S) in the range 1.5≤S/Å^-1≤15.5. In this case, the cell dimensions of the model were determined by using the density of the glass. The coordination number of Na atom was estimated to be 5.5 from the second peak area after subtracting the contributions of O-O and B-B pairs. According to the model, an interconnecting diborate group distance was 5.7Å, and this value suggested the existence of non-bridging oxygen atoms because of the rather long inter-group separation.

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The terahedral site preference of Zn²⁺ and the octahedral site preference of Ni²⁺ and Cr³⁺ are significantly stronger than those of any other divalent or trivalent cations found in pseudobrookite structure such as Mg²⁺, Fe²⁺, Co²⁺, Al³⁺ and Fe³⁺. The purpose of this paper is to investigate the influence of site preference of Zn²⁺, Ni²⁺ and Cr³⁺ upon the formation of pseudobrookite type solid solutions.
Specimens are prepared by calcining a mixture of each oxide, hydroxide or basic carbonate for 1-20h at 1100°-1550°C. The formation of single phase solid solution is examined by X-ray analysis, and the lattice parameters are calculated. The absorptions of Co²⁺, Ni²⁺ and Cr³⁺ in the pseudobrookite structure are discussed by measuring the spectral reflectance. The results are summarized as follows.
1) Calcined products with the composition of ZnO2TiO₂, NiO2TiO₂ and Cr₂O₃TiO₂ are confirmed by X-ray analysis to be the phase assemblage of 2ZnOTiO₂+TiO₂, NiOTiO₂+TiO₂ and Cr₂O₃ 2TiO₂+Cr₂O₃, respectively.
2) Continuous solid solutions are obtained in xCoO(1-x)MgO2TiO₂. The phase of CoO₂TiO₂ being unstable towards decomposition into the phase assemblage of CoOTiO₂+TiO₂ below 1100°C, quenching is necessary to obtain the single phase of CoO2TiO₂.
3) Since Co²⁺ shows a tetrahedral site preference resulted from its electronic configuration 3d⁷, and occupies also an octaheral site in pure CoO, reflectance curve of Co²⁺ in pseudobrookite structure resembles simultaneously to that of Co²⁺ in ilmenite structure (CoO₆) and in wurtzite structure (CoO₄).
4) The incorporation of Zn²⁺ into MgO2TiO₂ on substitution of Mg²⁺ for Zn²⁺, is ca. 80mol%.
5) The pseudobrookite structure is maintained on substitution of ca. 50mol% of Mg²⁺ for Ni²⁺ in MgO2TiO₂.
6) Since Ni²⁺ shows a strong octahedral site preference resulted from its electronic configuration 3d⁸, and occupies an octahedral site preferentially, the reflectance curve of Ni²⁺ in pseudobrookite structure resembles to that of Ni²⁺ in ilmenite structure (NiO₆), but differs from that of Ni²⁺ in the tetrahedral site in spinel and phenacite structures.
7) The pseudobrookite structure is maintained on substitution of ca. 40mol% of Co²⁺ for Zn²⁺ or Ni²⁺ in CoO 2TiO₂.
8) The incorporations of Cr³⁺ into Al₂O₃TiO₂ and Fe₂O₃TiO₂ on substitution of Al³⁺ or Fe³⁺ for Cr³⁺ are only ca. 10mol%.

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A batch mixture of the nominal composition 2BaO⋅1.4ZnO⋅0.6FeO⋅6Fe₂O₃+0.3(2BaO⋅4ZnO⋅4B₂O₃) (Table 1) was melted in a Pt 10 Rh crucible at 1470°C for 2h. During melting, the melt was stirred with a Pt spatula every 30min. The crucible was then taken out of thefurnace and allowed to cool naturally. The polycrstalline ingot obtained in the crucible was remelted, except its lowest part 5mm thick, in the temperature gradient furnace by keeping the temperatures of its top and bottom at 1450°C and 1300°C, respectively (Fig. 1). After 10h, the both temperatures were lowered at the same rate of 5°C/h to solidify the melt upwards at a rate of 1mm/h. The lowest part of the ingot left unmolten acted as seed crystals. The thermal gradient in the melt was kept at 50°C/cm during solidification. The resultant ingot was composed of many Ba₂(Zn, Fe²⁺)₂Fe₁₂O₂₂ columnar crystals 1-3mm in diameter elongated with its ‹100› direction parallel to its solidification direction (Figs. 2 and 4, Table 2). A thin glassy film formed at the grain boundaries of the columnar crystals relieved effectively by its viscous flow the thermal stresses caused by a large difference in thermal expansion between a- and c-axis, thus suppressing the formation of microcracks in the ingot (Figs. 5 and 6). The apparent porosity of the ingot achieved was 0.3% (Table 3). The permeability of the ingot in its solidification direction was higher than that of a sintered ceramic of the same composition, but lower than that of Ba₂Zn_1.98Fe_0.02Fe₁₂O₂₂ single crystal in its c-plane (ref. 7). Attempt to prepare the ingots of the compositions 2BaO⋅2ZnO⋅6Fe₂O₃ and 2BaO⋅1.4ZnO⋅0.6FeO⋅6Fe₂O₃ by the same method as described above proved abortive, because many microcracks were formed in their resultant ingots (Tables 2 and 3).

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The process of the crystallization of the solid solutions in the system ZrO₂-CeO₂ were studied under hydrothermal conditions. Samples prepared by coprecipitation method were treated under 100MPa at 600°C for 2-72h using distilled water or the solution of alkaline metal (Li, Na, K) fluorides, chlorides, bromides, carbonates, nitrates, sulfates, or hydroxides as mineralizers.
Monoclinic zirconia (m-ZrO₂s.s.), ceria (CeO₂s.s.), and/or ZrO₂-rich solid solution (C₁s.s.) phases were produced by the hydrothermal treatments of coprecipitated samples. The crystallite size of these phases and the production of C₁s.s. depended on the species of anions used as the mineralizes.
The crystallite of m-ZrO₂s.s. was grown larger than that of CeO₂s.s. in the solution of fluorides, carbonates, or hydroxides. The crystallite of CeO₂s.s. was grown larger than that of m-ZrO₂s.s. in the solution of chlorides, bromides, or sulfates. The crystallite of m-ZrO₂s.s. and CeO₂s.s. did not increase significantly in the solution of nitrates or distilled water. In the solution of chlorides and bromides, C₁s.s. was produced in addition to m-ZrO₂s.s. and CeO₂s.s..
The effect of each mineralizer might be different in the crystallization process which consists of the dissolution/precipitation and the structural rearrangement. The fluorides, carbonates, and hydroxides enhanced the dissolution/precipitation process, while the chlorides and bromides enhanced the structural rearrangement process in the crystallization of the solid solutions in the system ZrO₂-CeO₂.

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The temperature dependence of the Vickers microhardness (VMH) was measured for highly dense Si₃N₄ ceramics without and with oxide or nitride additives prepared by the high pressure hot-pressing or hot isostatic pressing. Rapid increase in room temperature VMH of the Si₃N₄ ceramics without additives with decreasing the amount of open pores was observed. The VMH (200g loads) of the fully dense Si₃N₄ ceramics without additives was 23GN/m² at room temperature and 14GN/m² at 1200°C, and this VMH at elevated temperature was higher than that of SiC single crystal. The VMH of Si₃N₄ ceramics obtained from α-Si₃N₄ was higher VMH not only at room temperature but also at elevated temperature than those obtained from β-Si₃N₄. The decrease in the VMH with increasing temperature for the Si₃N₄ ceramics with oxide additives was more rapid than that for the Si₃N₄ ceramics with nitride of the same element, and it was found that controlling the composition of the grain boundary phase was very important in the fabrication of Si₃N₄ ceramics. It is expected that rapid fall in the VMH of the Si₃N₄ ceramics with additives of elevated temperature was due to the ductile-brittle transition of these materials.

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Spark-source mass spectrometry was used in order to determine the impurity elements from Li to La in nine commercial samples of Si₃N₄ raw materials. Total contents of thirty three impurity elements detected from Si₃N₄ raw powders which were prepared by a reaction of Si and N₂ were 1.0 to 2.2wt%. Otherwhile there were few kinds of impurities in samples which were prepared by reactions of pure SiCl₄-NH₃ and SiO₂-C-N₂, and total impurity contents was 0.07-0.14%. Three-point bending strength at 1200°C for the hot-pressed body from α-rich powder with 2wt% Al₂O₃ and 5wt% Y₂O₃ was decreased with the total impurity contents. Similar correlations were observed between the 1200°C-strengths and respective contents of Ca, Ti or Fe. However the room temperature strength was independent on the total impurity contents. Hot-pressed bodies from β-, α≅β- and amorphous powder showed lower strengths than those expected from the correlation curve for α-rich powder.

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