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  • Question
  • Spalling resistance of a refractory can not be increased by


  • Options
  • A. increasing its porosity.
  • B. using a coarser grog during its manufacture.
  • C. decreasing its thermal co-efficient of expansion.
  • D. making it denser.

  • Correct Answer
  • making it denser. 


  • Refractory Technology problems


    Search Results


    • 1. Chromite refractories are

    • Options
    • A. acidic refractory.
    • B. neutral refractory.
    • C. basic refractory.
    • D. fired at a temperature of 600°C only.
    • Discuss
    • 2. 'Super refractories' are made from pure

    • Options
    • A. carbides
    • B. oxides
    • C. borides
    • D. nitrides
    • Discuss
    • 3. Fireclay refractories have

    • Options
    • A. low co-efficient of thermal expansion.
    • B. poor thermal spalling resistance.
    • C. tendency to expand unduly high during firing.
    • D. very high cost.
    • Discuss
    • 4. Which of the following is not an acidic refractory?

    • Options
    • A. Silica bricks
    • B. Fireclay bricks
    • C. Bauxite bricks
    • D. Magnesia bricks
    • Discuss
    • 5. Which is the most stable crystalline form of silica at room temperature?

    • Options
    • A. Quartz
    • B. Cristobalite
    • C. Tridymite
    • D. None of these
    • Discuss
    • 6. Alumina-graphite bricks are used for lining the

    • Options
    • A. slide gate in teeming laddies.
    • B. continuous casting systems.
    • C. both (a) and (b).
    • D. neither (a) nor (b).
    • Discuss
    • 7. Zirconia refractory

    • Options
    • A. does not react with basic slags.
    • B. is produced from baddeleyite.
    • C. can not be used as an insulator.
    • D. has poor electrical conductivity at high temperature.
    • Discuss
    • 8. With increasing alumina content, the fusion point of high alumina refractories

    • Options
    • A. increases.
    • B. decreases.
    • C. remains constant.
    • D. may increase or decrease ; depends on its alumina content.
    • Discuss
    • 9. Which of the following does not occur during firing/burning of refractories?

    • Options
    • A. Removal of water of hydration.
    • B. Vitrification.
    • C. Decrease in crushing strength.
    • D. Development of stable mineral form.
    • Discuss
    • 10. Cermets are

    • Options
    • A. composite material containing both ceramic & metallic constituents.
    • B. having high strength & resistance to high temperature.
    • C. used in space vehicles, missiles & nuclear energy plants.
    • D. all (a), (b) and (c).
    • Discuss


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