Refractories, thermal properties

The industrial value of furfuryl alcohol is a consequence of its low viscosity, high reactivity, and the outstanding chemical, mechanical, and thermal properties of its polymers, corrosion resistance, nonburning, low smoke emission, and exceUent char formation. The reactivity profile of furfuryl alcohol and resins is such that final curing can take place at ambient temperature with strong acids or at elevated temperature with latent acids. Major markets for furfuryl alcohol resins include the production of cores and molds for casting metals, corrosion-resistant fiber-reinforced plastics (FRPs), binders for refractories and corrosion-resistant cements and mortars. 

Thermal Properties. Refractories, like most other soHds, expand upon heating, but much less than most metals. The degree of expansion depends on the chemical composition. A diagram of the thermal expansion of the most common refractories is shown in Figure 1. 

Isostatic molding, 18 300 Isostatic refractory pressing, 21 504 Isostearic acid, physical properties, 5 35t Isotachophoresis, 9 738, 742, 748 Isotacticity, of polypropylene, 20 529 Isotactic PB resins, thermal properties of, 20 417... 

Thermal Properties.—The thermal qualities of refractories, specific heat, conductivity and expansion are determined according to the established physical methods. It is evident that these properties are of considerable practical importance. The data available, however, on these subjects are quite meager, especially if it is considered that the structure of the manufactured product, irrespective of its chemical nature, is of paramount importance. Furthermore, these properties are subject to change with temperature and comparatively few constants are at hand to illustrate the character of these relations. It is known that the specific heat and thermal conductivity increase with temperature but the fundamental laws governing these changes have not been established. Furthermore, it must be realized that the structure of all these materials is certain to undergo physical changes which affect the thermal qualities. 

The metal has a hexagonal close-packed lattice and resembles other transition metals such as iron and nickel in being hard, refractory (m.p. 1680°+10°, b.p. 3260°), and a good conductor of heat and electricity. It is, however, quite light in comparison to other metals of similar mechanical and thermal properties and unusually resistant to certain kinds of corrosion and has therefore come into demand for special applications in turbine engines and industrial chemical, aircraft, and marine equipment. 

In the present world, the interest to oxygen-free refractory inorganic materials is growing with respect to the fact that it becomes the basis for various materials. The scientific interest is first related to the nitrides and carbonitrides with a number of unique properties such as high refractoriness, thermal resistance, chemical environment resistance, relatively low density, and so on. 

Table 4.2 Thermal Properties of Group IV Interstitial Carbides and Other Refractory Materials...

Table 8.4 Thermal Properties of Covalent Carbides and Other Refractory Materials at 20 C...

Table 11.2 Thermal Properties of Interstitial Nitrides and Other Refractory Compounds...

Because of these special properties, potential applications of the glass-ceramics are as refractories (thermal stablity at 1600 C), corrosion-resistant material for manufacturing equipment and installations, and as a pore-free material for radwaste containment. Electromelting is the preferred method for producing the base glasses. 

Table 7.1 Composition and Thermal Properties of Some Refractory Materials Used in Rotary Kilns...

These working conditions led to the selection of non-oxide refractory ceramics as fuel coating. Thus, carbides turn out to be great candidates thanks to their remarkable mechanical and thermal properties. However, their behaviour under irradiation has to be studied in more details. 

Addressing topics that include corrosion, applications, thermal properties, and types of refractories. An Introduction to Ceramics and Refractories provides you with a basic knowledge of the fundamentals of refractories and ceramics and presents a clear connection between refractory behavior and ceramic properties to the practicing engineer. 

Typical ceramic refractory materials used in the hearth wearing surface are shown in Table 8. Note that the thermal conductivities of ceramic refractories (insulating) are significantly lower than any carbonaceous refractory. The properties and characteristics of all ceramic refractories depend on the type, quality, and source of the raw materials utilized in their mix and the particle size makeup. 

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