Thermal Diffusivity and Thermal Conductivity Questionnaire

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40) Thermal diffusivity and thermal conductivity are interchangeable equivalent terms.
41) Refractory grade silicon carbide is synthesized using the Acheson process.
42) Radiative thermal transfer in fibrous insulations can be reduced by using thicker fibers.
43) Phosphate bonded alumina refractory manufacturing requires sintering at >1200°C.
44) The endpoint of a pyrometric cone is not a function of heating rate.
45) Silica is an important additive to achieve high refractoriness in magnesia-based refractories.
46) A thermopile output is the sum of the EMF’s of individual thermocouples in parallel.
47) Silica additions degrade the hot strength, creep resistance and corrosion resistance of magnesite refractories.
48) Hysteresis in the thermal expansion behavior of zirconia is due to phase transformations.
49) Hysteresis in the thermal expansion behavior of Al,TiO; is due to thermal expansion anisotropy.
50) Silica refractories exhibit low resistance to acidic slags in steelmaking.
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51) The term “flux factor” characterizes the propensity of a silica refractory for dissolving in molten steel.
52) Type A silica refractories are characterized by a “flux factor” greater than 0.5.
53) Deadburned magnesite brick is employed wherever good basic slag resistance is required.
54) Spinel modified magnesite refractories were developed as a substitute for chrome-magnesite.
refractories for use where hot strength and spall resistance are required.
55) Debye determined that Cu = 3 R cal/gram atom-K at 20 K for all materials.
56) Beta-Eucryptite is a “stuffed derivative” of quartz with a small volume thermal expansion coefficient.
57) A good approximation for the molar heat capacity of aluminum oxide at 1300K is 30 cal/mole-K.
58) A good value for the thermal expansion of alumina at 1000 K is 8.9 x 10-6 0C-1.
59) The thermal energy required to raise the temperature of a porous ceramic is lower than
the energy required to heat the same ceramic in a dense form to the same temperature.
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