A method for the exact and simple determination of the water in glass is proposed. The procedure is as follows:
Water in glass sample is liberated at 1250°C in oxygen carrier gas with the addition of copper as decomposition aid. The water liberated reacts with calcium carbide to acetylene (C₂H₂) and the C₂H₂ is trapped by freezing. The C₂H₂ is finally determined by gas-chromatograph with a flame ionization detector.
Borosilicate and soda-lime glasses have been analyzed with a very good precision. Analytical results are compared with those of infrared absorption measurements and they agree well.

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Recently, desulphurization of molten pig iron is usually carried out in torpedo car by calcium carbide or calcium oxide. In this paper, mechanism of wear of high aluminous refractories by slag containing calcium carbide was studied. Microstructure of cross sections of the refractories used in torpedo car shows that dense reacted zone with isolated corundum crystals and altered zone with a number of cracks were formed in the side of working face. Basicity (CaO/SiO₂) of the slag in torpedo car increased from 0.1-0.4 to 1.6-4.5 during desulphurization. Mechanism of reactions between high aluminous refractories and several kinds of synthetic slags composed of calcium carbide and/or blast furnace slag was studied. The blast furnace slag dissolved the refractories much more than the other slags did. In the reacted zones, metallic silicon particles and needle-like corundum crystals were formed. The silicon is considered to be formed as a result of reduction of silica in the refractories by CaC₂. The reduction of silica or formation of minerals such as calcium aluminates or calcium aluminum silicates may result in the crack formation. In conclusion, wear of refractories in the slag line of torpedo car would proceed by the repetition of the following steps: (1) the formation of reacted zones and altered zone with a number of cracks during desulphurizing operation, and (2) the dissolution of the reacted zones into low basicity slag.

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Ceramics are typical brittle materials, and fracture occurs owing to crack initiation caused by stress. Therefore, it is very important to measure the fracture toughness for evaluating the mechanical properties of ceramics. In this work, the fracture toughness of various kinds of ceramics were measured by the bending fracture of notched beams, and also the effect of testing conditions were examined from the stress-distribution of two dimensional photoelasticity experiment with epoxy-resin models. As a result, the notch depth was an effective factor on the K_Ic value, and the notch width was the most effective one. The effect of testing span was also recognized in the test of silicon carbide, And energy release ratio g_Ic is calculated from the obtained K_Ic value and experimental elastic constant of ceramics which was measured by means of ultrasonic pulse echo method. HPSN shows the biggest value of g_Ic from 160 to 220J/m² whereas the g_Ic of HPSiC was the smallest value 33J/m², and this result indicates that the latter material fracture easily. In general, the K_Ic values of ceramics increase as the width of notch become larger, the testing span smaller, and the depth of notch larger. It is because these factors mentioned above increase the fracture load relatively. In the three-point bending test, the smallest value of K_Ic for ceramics was obtained from the testing condition in the notch width and depth of 0.3 and 1.25mm, the testing span of 40mm, and specimen size of 5×5×60mm long, in this study. The ceramic materials, the K_Ic values of which are liable to increase, have larger values of E/σ_b, and this result showed that the elastic properties gave the effect on the measurement of K_Ic values for ceramics.

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Gas-chromatographic and chemical analyses of reaction products during the synthesis of ultramarine from kaolin, Na₂CO₃, active charcoal and sulfur revealed that Na₂CO₃ easily decomposed under the presence of sulfur even at 450°C and thus formed Na₂O reacted with kaolin in the ratio of Na₂O:Al₂O₃⋅2SiO₂⋅nH₂O=1:1. Simultaneously formed NaOH from Na₂O and H₂O reacted with sulfur according to the following equation: (4+2α)NaOH+(3+αx+x-α)S→(1+α)Na₂S_x+(2-α)H₂S+Na₂SO₄+2αH₂O. Above 500°C, reduction of Na₂SO₄ to Na₂S_x by active charcoal occurred with the evolutions of CO, COS and CO₂. From the surface area measurements of kaolin and Na₂O⋅kaolin, it was assumed that Na₂S_x, forming more than 7 layers extensively covered the surface of Na₂O⋅kaolin. CS₂ or SO₂ introduction on to Na₂S_x led to the formation of S₃^- (blue chromophor). This fact indicates the important roles of CS₂ and SO₂ in the ultramarine blue synthesis.

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Stable shape of α-SiC bicrystal joined at (0001) or (1010) boundary and the shape of β-SiC bicrystal joined at (111) boundary is calculated supposing various grain boundary energy. The results obtained are compared with the knowledges already reported. Conclusions obtained are as follows:
1) The difficulty of sintering of highly pure SiC powder particles is mainly caused by the fact, the relaxation of surface energy by the formation of grain boundary being generally very small.
2) The dihedral angle between crystals joined at a certain grain boundary does not reflect the balance of surface tention or energy between surfaces and the grain boundary. It is to be recognized as a result appeared so as to relax total surface and grain boundary energy.
3) The surface tension of highly pure SiC crystal is considered to be fairly small in contrast with the surface energy, and it will not bear important role in the progress of sintering.

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The coordination number of Ge in Na₂O⋅4GeO₂ glass was investigated by means of the Ge-EXAFS (Extended X-ray Absorption Fine Structure) above its K-absorption edge. The Fourier transform method did not provide the correct information for this glass sample. By the parameter fitting method, which utilizes low-quartz type GeO₂ as the reference sample, the average coordination number and the nearest Ge-O distance in Na₂O⋅4GeO₂ glass were determined to be 4.55 and 1.79±0.005Å, respectively. These values agreed with those obtained with the X-ray diffraction method. The results give the proportion of 23±3% for six-coordinated Ge in Na₂O⋅4GeO₂ glass, when we assume that the Ge-O average bonding distances are 1.74Å in case of four-coordinated Ge and 1.90Å in case of six-coordinated Ge.

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The specimen of reaction bonded silicon nitride with chevron notch angle of 120° were fractured by three-point bending with test span of 42mm. The fracture test were carried out under a constant cross-head speed of 0.023mm/min in nitrogen, air or oxygen atmosphere at a elevated temperature of 1400°C. The stress intensity factor (K_I) were calculated from the compliance analysis of load-deflection (time) curves of the stable fracture. And the corresponding crack velosity (V) were also calculated by the comparison of the theoretical compliance of the specimen calculated by using Bluhm's slice method, with the time change of compliance in the measured load-deflection curves. The value of V obtained from the above treatments showed that lower p_O2 atmosphere resulted higher crack velocity, although one expects that higher p_O2 atmosphere may result higher crack velocity from the promotion of stress corrosion by oxygen. The fracture surface in N₂ was intergranular one, and the fracture surfaces in air or O₂ were rather flat one covered with glassy phase including α-cristobalite crystal which was the result of the oxidation of silicon nitride. In the slow crack growth of silicon nitride at high temperature, stress corrosion may become active in higher p_O2 atmosphere by the chemical reaction of oxygen with silicon nitride, but the chemical reaction also must lead the crack blunting at crack tips. v in higher p_O2 atmosphere may be reduced by the blunting effect. In connection with above discussion, a few problems for measuring and evaluating the K_I-V relation of brittle materials such as ceramics are described.

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Density, viscosity and surface tension of melts in the system SiO₂-TiO₂-Al₂O₃ at 1600°C have been measured by means of the Archimedes' method with two spheres, the drawing sphere method and the Wilhelmy's method, respectively. The accuracies of these measurements were confirmed with the molten B₂O₃ in the temperature range from 400° to 1400°C. As the result, density and viscosity of the molten B₂O₃ approximately agreed with values of literatures, but surface tension was affected by viscosity of the melt. However, influence of viscosity of the melt on surface tension could be taken off by a modification of “intermittent lowering”. When the contents of Al₂O₃ in the system SiO₂-TiO₂-Al₂O₃ were in the range from the eutectic composition of the system SiO₂-TiO₂ (89.5wt% SiO₂, 10.5wt% TiO₂) up to about 12.5wt% Al₂O₃, all the values of density, viscosity and surface tension of the melts decreased with increase of Al₂O₃ content. Above 12.5wt% Al₂O₃, these values increased with increase of Al₂O₃ content because of the formation of mullite in the melt.

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The structure of 3B₂O₃⋅Na₂O glass has been investigated by the radial distribution function method based on X-ray scattered intensity data. Peaks in the correlation curve were observed at r=1.40, 2.40, 3.65, 4.15, 4.55, 5.9 and 6.4Å. Each boron atom was surrounded by 3.1 oxygen atoms on the average at a distance of 1.40Å. The reduced intensity S⋅i(S) curve is interpreted by comparison with the calculated S⋅i(S) curves for α-3B₂O₃⋅Na₂O and β-3B₂O₃⋅Na₂O quasi-crystalline models of the glass structure. Both model gave a good agreement between the calculated and observed S⋅i(S) curves in the range 1.5≤S/Å^-1≤15.5, however, relative to the model after β-3B₂O₃⋅Na₂O, the model after α-3B₂O₃⋅Na₂O which consists of pentaborate and diborate groups in equal amounts gave a better agreement. In this model, the coordination number of sodium atom was 5.7 and the estimated value from the second peak area after subtracting the contributions of O-O, O-B and B-B pairs was 6.0.

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Some β-sialons and AlN-sialons were fabricated by hot-pressing of the nitrided compacts made from SiO₂, Al and Si, or SiO₂ and Al in N₂, and their thermal expansions were measured by dilatometric method.
Thermal expansion coefficient of β-sialon (Si_6-zAl_zO_zN_8-z) were measured as 2.86, 3.23, 3.40 and 3.54×10^-6/°C (25°-1000°C) for z=1, 2, 3 and 4 composition, respectively. The values of z=1 and 2 β-sialons were lower than those mesured for hot-pressed Si₃N₄ with 5% Y₂O₃ and 2% Al₂O₃ additives (3.47×10^-6/°C) and reaction-bonded Si₃N₄ (3.31×10^-6/°C). Higer values of z=3 and 4 β-sialons were considered to be due to small amount of X-phase coexisted with β-sialon. Termal expansion coefficient of AlN-sialons were 5.61-5.58×10^-6/°C (25°-1000°C) which are similar to that of hot-pressed AlN.
There were little difference among the different AlN polytype phases. Composite material composed of β and 15 R-AlN-sialons gave the value of 4.56×10^-6/°C which was an intermediate of those of β and 15R-AlN-sialons.

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