Oxide melts binary systems

BaO—Si02 55). At equimolar compositions above 20 mole-% metal oxides, the expansivity is in the descending order of K, Na, Li, Ba, Sr, Ca, and Mg and is inversely proportional to the so-called ion-oxygen attraction defined as I = 2ze /r2 where z is the cationic valence, e is the electronic charge, and r is the separation between the metal and oxygen ions 55). The ionic nature of these melts is further confirmed. Relationships were also obtained between the cationic radii and molar volumes which suggest that the volumes of the silicon-oxygen anions at any composition are comparable for all the binary systems 55). 

E. Peligot said that after being melted, the peroxide requires a much lower temp, for its solidification, for at —16° the compound remains liquid, and J. Fritzsche said that it can be re-solidified only at —30° because a little nitric acid has been formed, and this also accounts for the turbidity of the cooling liquid. For the fusion curve with nitric oxide, vide supra, nitrogen trioxide. P. Pascal studied the f.p. of binary systems of nitrogen peroxide with bromoform, chloroform, carbon tetrachloride, bromobenzene, methyl iodide, chloropicrin, and camphor. 

The Hf-B-C system presents a situation that falls somewhat between the Ti and Zr systems [60]. Although the HfB phase is stable in the Hf-B binary system, it melts at 2100°C, below the melting point of the Hf parent metal (2227°C). During a directed metal oxidation reaction of molten Hf with B4C at just above the melting point of Hf, e.g., 2400°C, the Hf-B-C isothermal ternary cross section (Fig. 18) indicates that the molten metal is... 

Abstract Aluminates form in binary systems with alkali, alkaline earth or rare-earth oxides and share the high melting point and resistance to chemical attack of the pure A1203 end-member. This means that these ceramics have a variety of applications as cements, castable ceramics, bioceramics, and electroceramics. Calcium aluminate cements are used for example in specialist applications as diverse as lining sewers and as dental restoratives. 

The K2Cr207 is known to melt at 397.5 °C [114], and hence the chloride melt-K2Cr207 system may be considered as a binary liquid one. Subsequent heating of molten potassium dichromate causes its decomposition with the formation of Cr compounds in lower oxidation states according to the reference data [138], this begins at 600 °C. Nevertheless, diluted solutions of K2Cr207 are stable enough even at 700 °C. 

In conclusion, in this study the sol-gel synthesis of ZnO nanoclusters embedded in silica has been faced by the gel-derived binary system ZnO-Si02. As compared to oxide mixtures prepared by conventional solid-state reactions, in gel-derived systems the formation of ceramic silicate compounds is observed at lower temperatures than expected for traditional melting processing [173]. Through XPS it was possible to evidenee the importance of the choice of proper precursor compounds and proper annealing conditions to produce stable ZnO guest clusters dispersed into the host silica glassy matrix. 

In the binary glass-forming systems of alkali metal borates, it is possible to observe change in the trend of a number of physico-chemical properties in the concentration range of approximately 20 mole % of alkali metal oxide. This phenomenon is known in the literature as boric acid anomaly , and it is due to the change in the structure of the B2O3 melt caused by the alkali metal oxide addition and is related to the ability of boron to change its coordination number. 

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