Effect of boron nitride addition on some properties of aluminosilicate refractories

Conclusions An addition of 10–60 wt.% of boron nitride significantly alters the thermal conductivity, thermal expansion, and the elastic modulus of aluminosilicate refractories.As the boron nitride content is increased from 1–60% the strength of specimens heated in a nitrogen atmosphere with an oxygen content of 0.02% decreases.During cyclic heat treatment in an oxidizing atmosphere between 900 and 20°C additional bonds develop between the particles of the aluminosilicate and the oxygen-free additive. As a result the strength of the specimen increases.The thermal shock resistance of the specimens increases with an increase in the amount of boron nitride addition. Specimens with 40–50% boron nitride addition are in practice insensitive to temperature drops in the range 20–2400°C.Aluminosilicate refractories with the addition of 30–40 wt.% of boron nitride can be used as lining material in high temperature systems with brief nonsteady or cyclic work schedules.Translated from Ogneupory, No. 4, pp. 36–39, April, 1968.     

Effect of fillers on the supermolecular structure and properties of polyformaldehyde

The authors studied the effect of fillers (silica and aluminum silicate) of various particle size and shape on the supermolecular structure, hardness, wear resistance, and compressive strength of polyformaldehyde (PFA). It was found that these properties are improved only by small filler additions; at higher filler concentrations the mechanical properties of PFA deteriorate and a change takes place in the character of wear of this material.     

Change in the phase composition of porcelain on cooling

Glass and Ceramics -