Solid state reactions between sintered Nb₂O₅ and CaO have been studied in Ar at the temperature range from 1150°C; to 1300°C. The reaction layers formed at the Nb₂O₅-CaO interface were examined by using electron microscopy, EPMA, X-ray diffraction and dilatometry. The following results were obtained.
At 1150°C and 1200°C, three layers (CaO⋅Nb₂O₅, 2CaO⋅Nb₂O₅ and a phase mixture of cubic 3CaO⋅Nb₂O₅ and orthorhombic compound) and at 1250°C and 1300°C, four layers (CaO⋅Nb₂O₅, 2CaO⋅Nb₂O₅ cubic 3CaO⋅Nb₂O₅ and a phase mixture of cubic 3CaO⋅Nb₂O₅ and orthorhombic compound) were formed. These results indicated that the one-way diffusion of CaO into Nb₂O₅ occurred. The order in width of the reaction layer was the phase mixture, cubic 3CaO⋅Nb₂O₅, 2CaO⋅Nb₂O₅ and CaO⋅Nb₂O₅. The orthorhombic compound was richer in CaO content than 4CaO⋅Nb₂O₅. No compound richer in CaO content than orthorhombic compound was found in the temperature range 1150°C to 1300°C.

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Time dependence of ionic conduction in arc-fused single crystals of yttria-stabilized zirconia (YSZ), (Y₂O₃)_x(ZrO₂)_1-x, (x=0.085 and 0.12) was studied. In the first stage the electrical conductivity of the as-grown single crystals was 1.3 times higher than that of poly-crystalline YSZ (in the case of x=0.085). Upon heating in air, the electrical conductivity was decreased. The rate of decrease was a first-order kinetics with a rate constant of 3.2×10^-2h^-1 at 800°C. The transport number measured with oxygen concentration cell was above 0.98 both for the as-grown and the heated single crystals. Therefore the decrease in conductivity was interpreted to be a result of the decrease in oxygen ion conduction. From UV-visible absorption spectra it was shown that the non-stoichiometric oxygen deficient defect was present in the as-grown single crystals and it decreased upon heating. The difference in linear thermal expansion between bulk length and lattice parameter suggests that the oxygen deficient defect is an interstitial cation and the oxygen ion conduction is enhanced by this defect.

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Titanium K band X-ray emission spectra for alkali titanium silicate glasses were determined by means of an electron probe X-ray microanalyser (EPMA) in order to obtain informations about co-ordinated states of titanium ions in the glasses. The measurements were also carried out on several crystals of known structures, such as rutile-type TiO₂, Na₂TiSi₄O₁₁ (narsarsukite), BaTiO₃, CaTiO₃, MgTiO₃, Mg₂TiO₄ and Ba₂TiO₄. The measuring conditions for the third order of reflection of K_{β1, 3}-emission spectra of titanium (TiK_{β1, 3} (3)) were as follows: the accelerating voltage 30kV, the sample current 0.08μA and the electron diameter 50μm. TiK_{β1, 3} (3) band spectra was analysed by a ADP crystal and a gas filled proportional counter. The peak positions of TiK_{β1, 3} (3) were used to discuss the dependence of chemical shift upon the co-ordinated states of titanium ions in the compounds with TiO₂.
The results for the crystals, which have tetrahedrally or octahedrally co-ordinated titanium ions revealed that the peak position of TiK_{β1, 3} (3) band spectra shifted toward longer wavelength when the co-ordination number of titanium ions changed from six to four. For alkali titanium silicate glasses, the peak positions lied between those of crystals but the degree of shift depended upon the amount of TiO₂ substituted for SiO₂. From these results, it was concluded that in alkali titanium silicate glasses the co-ordination number of titanium was six when TiO₂ content is low, changed to lower number from six as TiO₂ is substituted for SiO₂ up to about TiO₂/SiO₂=1, and then turned back to six when further substitution of TiO₂ for SiO₂. It was also found that the change of the co-ordinated state of titanium ions in alkali titanium silicate glasses was not affected by the kind of alkali oxide and that the titanium ions of low co-ordinated states changed to the six co-ordinated state upon crystallization.

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Since recently industrial use of glass has become very wide, many problems have required a more strict understanding of surface phenomena of glass such as contamination or weathering which have been empirically treated.
In this paper the results of ESCA measurements of carbon on float glass which was formed as the result of contamination and wheathering were reported and its chemical state and origin were discussed.
In carbon 1s spectrum of hexan rinsed float glass, both top and bottom surfaces showed two peaks and there were parts on bottom side which showed the third shoulder peak.
To attribute these peaks, carbon 1s was measured for the fused silica glass, the float glass which were stored in the vessel with good ventilation free from dust and organic vapor in air after removal of surface layer by ionetching, Na₂CO₃ and for CaCO₃.
These two peaks were considered as the result of the contact with CO₂ in atmosphere because same peaks were observed for the float glass stored in air.
In these two peaks the lower binding energy one was attributed to a species arising from absorbed CO₂ on surface silanol sites since its binding energy and intensity change with time were very similar to those of the fused silica glass stored in air.
The higher binding energy peak was assigned to a species like carbonate ion as the results of interaction between CO₂ and hydroxides of Na and Ca on surface since its binding energy agreed with Na₂CO₃ and CaCO₃ and it could not be observed for fused silica glass.
From the results of ESCA measurements of rations, however, the form of this carbonate-like species was considered to be somewhat different from the complete carbonate crystals.
These two peaks increased with time with constant intensity ratio initially but increasing rate of the higher binding energy peak became gradually small. The reason for this was considered that the silanol group increased by the reaction with water in air, whereas the supply of cations to surface tended to be retarded by the formation of cation depleted region under the surface.
The third peak observed on a part of bottom side was considered to be due to the contamination during manufacture since it was always observed on one side of a glass and did not appear on glass stored in air after ionetching.

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Aluminum sites in chrysoberyl (BeAl₂O₄), which has olivine type structure, were substituted with Cr, Fe or Ga, and the solubility limits were determined at 1400°C.
The BeAl₂O₄-BeCr₂O₄ system showed complete solubility range throughout the system. In the case of Fe, however, the compound of the composition BeFe₂O₄ was not formed by solid state reaction, and the solubility of Fe³⁺ in BeAl₂O₄ was limited at about 50mol%. Ferric ions are considered to substitute the Al_II sites of mirror symmetry, which have larger volume than Al_I sites of inversion symmetry.
In the BeAl₂O₄-BeGa₂O₄ system, two different crystalline phases were found, namely, chrysoberyl type (orthorhombic) and beryllium gallium oxide type (hexagonal).
The lattice parameters of BeAl_2-2xR_2xO₄ were shown below as functions of composition x.
BeAl_2-2xCr_2xO₄ (chrysoberyl type) a=5.476+0.187xÅ, b=9.406+0.388xÅ, c=4.427+0.128xÅ (0.0≤x≤1.0) BeAl_2-2xFe_2xO₄ (chrysoberyl type) a=5.476+0.275xÅ, b=9.406+0.518xÅ, c=4.427+0.157xÅ (0.0≤x<0.5) BeAl_2-2xGa_2xO₄ (chrysoberyl type) a=5.476+0.197xÅ, b=9.406+0.405xÅ, c=4.427+0.103xÅ (0.0≤x<0.37) BeAl_2-2xGa_2xO₄ (beryllium gallium oxide type) a=7.554+0.199xÅ, c=2.910+0.072xÅ (0.57<x≤1.0)
The lattice parameters of the hexagonal BeGa₂O₄ were a=7.7525 (3) Å, c=2.9817 (2) Å, z=2 and the density d_calc=4.541g/cm³ (at 25°C). This compound was about 23% less dense than the corresponding chrysoberyl type compound. Linear thermal expansion coefficients of BeGa₂O₄ were 3.29×10^-6 and 2.95×10^-6/°C parallel to a- and c-axis, respectively, in the temperature range between 25° and 900°C.

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The hydration products of the compounds in the system CaO-Al₂O₃ (i.e. CA_n:C₃A, C₁₂A₇, CA, CA₂ and CA₆) in phosphoric acid solutions at 35°C were studied by means of X-ray diffraction and TG-DTA methods and by SEM observation.
Tricalcium aluminate hydrates in pure water quickly to form C₃AH₆ within 1 hour, but the addition of phosphoric acid retards this hydration. The main hydrate of C₁₂A₇, CA and CA₂ was C₂AH₈ after 1 day, but C₂AH₈ gradually converted to C₃AH₆ in pure water or in dilute phosphoric acid solutions. The conversion from C₂AH₈ to C₃AH₆ was retarded in the mixtures with large ratio of water/CA_n in pure water. The addition of phosphoric acid also retarded the conversion from C₂AH₈ to C₃AH₆.
Morphological changes from the irregular plates or hexagonal plates of C₂AH₈ to the polyhedral grains of C₃AH₆ were observed by SEM in the specimens cured for 1 day, 10 days and 30 days at 35°C.
IR data suggested that phosphoric acid was rapidly adsorbed on the surfaces of CA_n grains as PO₄^3- or HPO₄^2- group.
A particular critical ratio of H³PO⁴/CAⁿ, above which the hydration of CA_n could not proceed, seemed to exist for each CA_n compound. It was assumed that phosphoric acid formed glass-like insoluble materials in the CaO-Al₂O₃-P₂O₅ on the surface of each CA_n, and that these insoluble layers retard hydration of CA_n.

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Sintering for 3Y₂O₃⋅WO₃ ceramics and effect of addition of CaO to 3Y₂O₃⋅WO₃ on the sintering were investigated by measuring shrinkage and relative density of the specimen. Flexural strength of all the compacts was also measured to study the effects of sintering conditions on the strength. A grain boundary diffusion might predominate in the initial stage sintering for 3Y₂O₃⋅WO₃. The apparent activation energy of the sintering was 81-91kcal/mol. Addition of CaO to 3Y₂O₃⋅WO₃ prevented grain growth of the specimen and remarkably increased in the sinterability. However, there was no sign of forming liquid in grain or grain boundary. Bulk diffusion might predominate in the initial stage sintering for 3Y₂O₃⋅WO₃ with CaO. The apparent activation energy of the sintering for CaO 1mol% doped 3Y₂O₃⋅WO₃ was 65kcal/mol. Addition of CaO to 3Y₂O₃⋅WO₃ increased in the flexural strength of specimen. Sintering at the higher temperatures for longer time scarcely decreased the flexural strength because of the grain growth of the specimen.

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Hot-pressed Si₃N₄ were prepared from two kinds of commercial grade Si₃N₄ with addition of MgO. Oxidation behavior of hot-pressed Si₃N₄ bodies were investigated in dry oxygen at 1200° and 1300°C, at several steps up to 30 days.
Results of the weight gain, X-ray diffraction analysis, EPMA analysis and SEM observations on the oxidized layer are discussed in relation to the mechanism of oxidation.

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