The change of internal friction was studied in two series of experiments, that is, electrolysis experiment and polarization experiment. The sample used in this work was the alkali silicate glass rod (Na₂O 35mol%, SiO₂ 65mol%) with a Au-Pd wire in the center.
(1) Electrolysis experiment; the internal friction was measured after an electric field (1.5V d.c.) was applied between the center and the surface of the sample at 270°C for 15 to 150h. The height of high-temperature peak increased when the surface was positive and decreased when the surface was negative. The height of low-temperature peak decreased in both cases.
(2) Polarization experiment; the internal friction was measured under the condition that an electric field (below 4.5d.c.) was applied between the center and the surface of the sample. The height of high-temperature peak increased in proportion to the applied field.
The above results support the following proposal; the increase of the height of high-temperature peak is due to the increase of the vacant holes of alkali ions near the surface, which contributes to the movement of non-bridging oxygen ions. The same phenomenon was also observed when alkali ions near the surface were taken off by the treatment with a crown-compound. The theories of Day et al. that the high-temperature peak is due to the presence of hydrogen ions do not, however, seem to explain successfully these experimental results. Consequently, it was pointed out in conclusion that the high-temperature peak of alkali silicate glass was due to the migration of non-bridging oxygen ions from their own sites to the vacant holes of alkali ions around them. All of the results in this work support reasonably the conclusion.
As for the low-temperature peak, there was no additional remark except that the lowtemperature peak is due to only a part of alkali ions. The deformation of the network around the vacant holes of alkali ions was observed as an increase of the background of internal friction.

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Phosphorus K band X-ray emission spectra for some simple phosphate crystals and alkali phosphate glasses were determined by using an electron probe X-ray microanalyser (EPMA) in order to obtain information about the chemical state of phosphorus ion and its surroundings. The samples used were BPO₄, AlPO₄, NaPO₃, Na₄P₂O₇, Na₃PO₄, KPO₃, K₄P₂O₇ and K₃PO₄ crystals and Na₂O-P₂O₅ (Na₂O: 40, 45, 50mol%) and K₂O-P₂O₅ (K₂O: 40, 45mol%) glasses. The measurements were performed with ADP crystal and a gas filled proportional counter under the conditions of the accelerating voltage 25kV, the sample current 0.02μA and the electron beam diameter 40μm. Both the peak position and shape of PK_β band spectra were found to change with composition of phosphate compounds. The peak positions, determined by taking the middle point of the width of the spectra at half-maximum intensity, were used to discuss the dependence of chemical shift of phosphorus ions on the structure of phosphate compounds.
The results for alkali phosphate crystals, which have the P=O type bond in their PO₄ tetrahedral units, revealed that the peak position of PK_β band spectra shifts linearly toward shorter wavelength with increasing the ratio of alkali content to phosphorus content, R/P. However, for BPO₄ and AlPO₄ crystals, which have no P=O type bond, the peak position does not fit to the value for a non-alkaline compound projected from the above linear line of alkali phosphate compounds but shifts toward longer wavelength. These results were interpreted by considering two effects of P-O tetrahedral type bond and electronegativity of the second neighbouring elements around phosphorus ions. On the basis of these results, the bonding nature of phosphorus ions in alkali phosphate glasses was discussed from the chemical shifts found for alkali phosphate glasses with R/P<1.

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The authors investigated the hydration behaviors of glassy 12CaO⋅7Al₂O₃ containing SiO₂ (3wt%) in the solution of CaSO₄⋅2H₂O or Ca(OH)₂. The results were summarized as follows:
(1) Glassy 12CaO⋅7Al₂O₃ hydrated more slowly than crystalline 12CaO⋅7Al₂O₃.
(2) The eluted quantities of CaO or Al₂O₃ from glassy 12CaO⋅7Al₂O₃-H₂O system were lower than crystalline 12CaO⋅7Al₂O₃, and they were CaO 0.6g/l, Al₂O₃ 2.2g/l at long time.
(3) Ettringite formed at the first period of the hydration in the saturated solution or the suspension of CaSO₄⋅2H₂O. And 3CaO⋅Al₂O₃⋅6H₂O formed in the saturated solution or the suspension of Ca(OH)₂, while C₂AH₈ formed from crystalline 12CaO⋅7Al₂O₃.

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In the phase diagram studies on the Al₂O₃-Ln₂O₃ systems, liquidus and eutectic temperatures of Al₂O₃-Ho₂O₃ and Al₂O₃-Er₂O₃ systems were measured from the cooling curves of specimens by the specular reflection method with a heliostat-type solar furnace. Quenched specimens from the melt were examined by X-ray diffractometry and chemical analysis.
Single phases of garnet type 3Ho₂O₃⋅5Al₂O₃ and 3Er₂O₃⋅5Al₂O₃, perovskite type HoAlO₃ and ErAlO₃, and monoclinic 2Ho₂O₃⋅Al₂O₃ and 2Er₂O₃⋅Al₂O₃ were observed when the mixtures with the corresponding stoichiometric composition were heated at 1600°C in an electric resistance furnace, and also when the specimen were cooled after fusion in the solar furnace.
Solidification point of three compounds for each system were as follows:
3Ho₂O₃⋅5Al₂O₃: 1950±20°C ErAlO₃: 1963±20°C 3Er₂O₃⋅5Al₂O₃: 1961±20°C 2Ho₂O₃⋅Al₂O₃: 1975±20°C HoAlO₃: 1980±20°C 2Er₂O₃⋅Al₂O₃: 1990±20°C
All of the above compounds appeared to be stable phase, because they showed no phase transition in the repeated heating and cooling cycles.
The Al₂O₃-Ho₂O₃ system shows four eutectics points were found at 1780°C, 1930°C, 1910°C and 1885°C at 19, 42.5, 60 and 78mol% of Ho₂O₃ composition, respectively.
In the Al₂O₃-Er₂O₃ system, four eutectics points were found at 1810°C, 1930°C, 1920°C and 1880°C at 18, 42.5, 57 and 80mol% of Er₂O₃ composition, respectively.
Each cooling curve of Ho₂O₃ and Er₂O₃ showed three and two exothermic peaks, respectively, corresponding to solid state phase transformations as well as solidification point.
High temperature phase diagrams for Al₂O₃-Ho₂O₃ and Al₂O₃-Er₂O₃ systems were presented.

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Melting and crystallization behaviors were studied on the solid solution system of fluorphlogopite [KMg₂(AlSi₃O₁₀)F₂] and tetrasilicic mica [KMg_2.5Si₄O₁₀F₂]. The solid solutions were synthesized by remelting the mixtures of two end members. And it was confirmed that complete series of solid solution isostructural with mica mineral were obtained.
Melting and crystallization behaviors were examined by quenching technique and DTA, after sealing the sample in a platinum crucible. Melting temperatures measured by two methods differed slightly, but indicated same tendency throughout the system. The melting temperature became lower with the increase in amount of tetrasilicic mica, and solid solutions melted gradually over a wide temperature range compared with end members. The single crystals of solid solutions were obtained from melts by taking advantages of the above results.

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Effect of addition of various borides was investigated on some properties of hot-pressing polycrystalline coke compacts made from calcined pitch coke powder with borides of 10wt% at temperature of 2100°C under a pressure of 200kg/cm₂.
All the boride give some effects on sintering and graphitization of coke powder. Among these borides, VB₂, CrB₂, Mo₂B₅, CrB, ZrB₁₂ and LaB₆ are more effective on sintering of coke comparing with other borides, and CrB₂ and ZrB₁₂ are more effective on graphitization of coke. In the borides of IVa and Va group, boron in the boride diffuses into coke, and accelerate of graphitization of coke, residual metal reacts with coke to form carbide. On the other hand, in the borides of VIa group, boron in the borides diffuses into coke, and boride become to low boron content compounds.
Acceleration of graphitization of coke is considered to be due to the diffusion of boron into coke. This behavior of graphitization is similar to the previous results on the addition of B₂O₃ or B₄C.

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Low-temperature viscosities in the range of 10^8.5-10¹³ poise were measured by penetration method for Na₂O-Al₂O₃-P₂O₅ and K₂O-Al₂O₃-P₂O₅ glasses containing 32-63mol% of P₂O₅. The plots of logη vs. 1/T (K^-1) showed linear relationships. The temperature (°C) at constant viscosities (logη=10, 11 and 12) rose with increasing Al₂O₃ content. In both systems the extent of the rise of the temperature with increasing Al₂O₃ content for the glasses of higher P₂O₅ contents was larger than that for the glasses of lower P₂O₅ contents. A remarkable difference in the viscosity change with the Al₂O₃ content was also found between the glasses with P₂O₅_??_42.5mol% and those with P₂O₅_??_37.5mol% in the Na₂O-Al₂O₃-P₂O₅ glass.
These changes of the viscosities with the glass composition were attributed to the marked structural difference between the glasses of higher P₂O₅ contents and those of lower P₂O₅ contents, that is, to the difference in the coordination number of the Al³⁺ in glasses (6-fold coordination in glasses with P/O≈0.33 and 4-fold coordination in those with P/O_??_0.25).

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Two kinds of boron carbide powders S-1 and S-2 were prepared by the reaction of boric oxide with carbon black in the presence of magnesium (2B₂O₃+6Mg+C=B₄C+6MgO). Powder S-1 was prepared by heat treating for 10min at 1500°C immediately after the reaction was completed, while S-2 was prepared by heat-treating at 1650°C. After purifying the powders, chemical composition of samples was analyzed. The boron contents in S-1 and S-2 were found to be 78.2±0.5at% and 76.2±0.5at%, respectively. A trace amount of Al, Mg, Si, Fe, Mn and Cu was observed, but total amounts of these impurities were estimated to be less than 0.1%, and the residual portion was regarded as solely consisted of carbon. Therefore the amounts of carbon were derived as 21.8 and 23.8at%, respectively. Then some boron and carbon were further added to the powder prepared, and the powder compacts were subjected to sintering for 1h at either 2200° or 2250°C in pure helium. It was found that boron carbide pellet with high density (>90%TD) could be obtained by using powders which contained C by 25 to 30at%, which corresponds to the region of eutectic point of B (or B₄C)-C system. In particular, boron carbide pellet with 93.7% TD was obtained by sintering the powder which contained C by 27.7at%.
It was concluded that excess carbon on grain boundaries in B₄C+C phase would inhibit grain growth during sintering. Simultaneously, due to the presence of carbon on grain boundaries, the melting point of interface of B₄C-C phase at the grain boundaries would decrease to that of eutectic point, thereby materials transport was enhanced. As a result of this effect, high density pellet was obtained in the region of carbon content by 25 to 30at%.

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The change in the pore size distribution and IR spectra of a gel with pyrolysis have been investigated to obtain necessary conditions for the low temperature synthesis of a monolithic silica glass.
The gel prepared by the hydrolysis of silicon tetramethoxide was porous containing micropores of the diameter ranging from 20Å to 80Å. And the higher the gelling temperature, the larger the porosity of the formed gel.
The dehydration polymerization reaction in the gel almost completed at 800°C. The collapse of micropores became extensive at temperatures above 650°C. The gel containing only small pores of the diameter about 20Å became almost pore free at 700°C, but resulted in the fracture into small pieces. The gel containing larger pores of 50Å-80Å, on the other hand, was still porous and monolithic with original shape at 800°C. Taking both these phenomena and the very small diffusion coefficient of water in the silica glass into considerations, the gel containing larger pores of the diameter 50Å-80Å was subjected to heat treatment up to 1000°C.
The gel was first heated in vacuum up to 250°C to remove the adsorbed water on the micropore wall. The gel was then exposed to air to complete the decomposition of residual organic compounds, followed by heating in vacuum again up to 800°C, to be held there until the water released by the dehydration polymerization went out of the gel through open pores. After the most of water had been expelled, the gell was heated up to 1000°C to be collapsed finally into silica glass free from micropores.
By this process, monolithic silica glasses of various shape were successfully prepared without hot-pressing.

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In line transmittances of transparent Y₂O₃ and black Y₂O₃ sintered pieces were measured and compared. In addition, total transmittance of transparent Y₂O₃ pieces was measured.
The grain size of Y₂O₃ powder was 4-6μm. The green compacts of Y₂O₃ powder were sintered at 2270°C (2543K) in an H₂ atmosphere to obtain transparent Y₂O₃ pieces. The transparent pieces were heated at 2000° (2273)-2200°C (2473K) in an H₂ (d.p. -36°C (237K)) atmosphere to make the Y₂O₃ pieces black.
The in-line transmittance of 0.75mm thick pieces was measured at the wavelength of 0.2-13μm. A 60W tungsten lamp was used for measuring total transmittance of the pieces.
The Y₂O₃ specimens were transparent in the 0.24-10.5μm wavelength. An 80% in-line transmittance was obtained at the 0.7μm wavelength and the maximum in-line transmittance was 84% at 6.3μm. The absorption coefficient of the specimens was approximately 3cm^-1 between 0.9-6μm. Absorption edges were found at 0.22 and 10.5μm.
Absorption peaks between 0.24-2.6μm were obtained at 0.458, 0.524, 0.646, 1.410 and 2.240μm with the Y₂O₃ specimens blackened at 2000°C (2273K). However, the Y₂O₃ specimens blackened at 2200°C (2473K) lost transparency in the wavelength between 0.24-0.7μm. Four absorption peaks were obtained with these black specimens.
Total transmittance of 82.3% was obtained with the transparent Y₂O₃ specimens.

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