Silicides of all the elements belonging to IV a, V a and VI a groups of the periodic table are electrically conductive and have high melting point and oxidizing resistivity. By the utilization of MoSi₂ which has the highest oxidizing resistivity among these suicides, a new heating element. has been developed It can be used at temperatures up to 1, 700°C in air.
Powdered MoSi₂ including polyvinyle-alcohol as binder was molded in rod through extrusion and then sintered at 1, 600°C in hydrogen atmosphere. The diameter of the heating element was made smaller at its main part and larger at its terminal parts where it was connected with a current-supply conductor, so that heat was mainly generated in the main part. Such construction was realized by manufacturing the main (heat generating) and the terminal parts separately and then welding them at 1900°C.
The flexural strength of the heating rod was 30kg/mm² at the heating part and still higher at the terminal parts. The electrical resistivity was 3×10^-5Ωcm a room temperature, and 5×10^-4Ωcm at 1, 700°C. The surface density of electric power to keep the surface temperature at 1, 700°C was 60W/cm² in the open air and reduced below one third in a closed room. The expansion coefficient was 8×10^-6°C^-1 at 1, 000°C. The coefficient varied almost linearly with temperature but had a point of inflextion at about 250°C, hence it is necessary for its cooling to be conducted slowly. At the temperature of about 1, 800°C it manifested plasticity and was able to be bent in any shape. This heat element is applicable in any atmosphere of oxidizing and reducing gases, nitrogen or vacuum.

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Most commercial products of ferrites are made by firing preformed powder mixtures of raw materials. This conventional method, however, is not adapted for obtaining products of the special shapes such as fiber and film. In this study we undertook to examine the possibility of obtaining magnetic materials from melted silicates containing Fe₂O₃ and MnO and of forming the melts into desired shapes by the ordinary glass-forming technique.
The compositions of the melts studied were of 7.5-20% Fe₂O₃, 7.5-20% MnO (or CoO and NiO), 0-5% Li₂O (or Na₂O and K₂O), 0-15% Al₂O₃, and 55-70% SiO₂(mole). The raw materials were ferrous oxalate, manganese dioxide, cobaltic oxide, nickel oxide, lithium-, sodium- and potassium carbonates, aluminium hydroxide and potter's flint powders. Their mixtures to yield about 50 gram of melts were heated in sintered-alumina crucibles in an electric furnace at temperatures from 1300° to 1400°C. Their melting behaviors and the workability of their melts into shapes of fiber or plate during cooling were investigated. X-ray diffraction analysis and magnetic measurement were made on materials quenched in air.
The results obtained are as follows:
1) The melts of the compositions, 7.5-15% Fe₂O₃, 7.5-20% MnO, 0-5% Li₂O (or Na₂O and K₂O), 5-15% Al₂O₃, 55-70% SiO₂ (mole) were fluid at temperatures 1300°-1400°C, and were able to be formed into desired shapes during cooling.
2) The intensity of magnetization of quenched specimens reached up to 18 gauss/g at the field of 10, 000 oersteds. Magnetization increased with increasing the content of Fe₂O₃ or Fe₂O₃+MnO, and decreased with increasing the content of Al₂O₃. The specimens of high Fe₂O₃ content saturated magnetically at a fairly weak magnetic field whereas the specimens of Fe₂O₃ content less than 15mole% did not saturate even at the field as strong as 5, 000-10, 000 oersteds. The followings are some examples of the composition which showed high magnetization and magnetic saturation at a weak magnetic field.
3) Separation of fine crystallites of spinel-type ferrites was confirmed by X-ray analysis in some of quenched specimens containing high amount of Fe₂O₃. The average size of the crystallites estimated from the broadening of X-ray diffraction peaks was 60-150Å.
4) Reheating quenched specimen generally increased the intensity of magnetization and also accelarated magnetic saturation at weak magnetic field.

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