This set of Engineering Materials & Metallurgy Multiple Choice Questions & Answers (MCQs) focuses on “Ceramics – 1”.
1. Which of the following is a property of ceramics?
a) Low strength
b) Low melting point
c) Resistant to corrosion
d) Bad insulation
Explanation: Ceramics are nonmetallic, inorganic solids which are used at high temperatures and therefore have a high melting point. They are good thermal and electrical insulators and possess good resistance to oxidation and corrosion. They are also strong, hard, and brittle.
2. Porcelain is a type of ______ ceramic.
Explanation: Whiteware is a type of ceramic product which contains porcelain, stoneware, china, pottery etc. It is not necessarily white but contains mostly clay, feldspar, and whiting. It finds application is tableware, wall tiles, sanitary ware etc.
3. Diamond and corundum are examples of _____ ceramics.
Explanation: Abrasives are a kind of ceramic materials which are used for making grinding wheels, abrasive cloth and paper. Diamond, carborundum, and corundum are common abrasive materials.
4. Which of the following is not a step in making ceramics?
a) Powder pressing
Explanation: Ceramics are made by pressing a powder into a compact, and then sintering. Some other ceramics are made by gluing the powders together, which is known as vitrification. Some compounds have metallic properties, but they are not alloys.
5. Which material is commonly used in electronic devices?
Explanation: Germanium (Ge) is a metalloid element frequently used in electronic devices. Silicon (Si) is also known to be used in semiconductors and other devices. Alumina is used as an electrical insulator, while Titania and Silica are used as pigment and abrasives respectively.
6. Which of the following carbides are used for cutting tools?
a) Silicon carbide
b) Tungsten carbide
c) Vanadium carbide
d) Chromium carbide
Explanation: Tungsten carbide (WC) belongs to the carbide class of engineering ceramics. It is used for cutting tools. Silicon carbide and boron carbide are used as abrasive, whereas vanadium carbide and tantalum carbide are used as wear-resistant materials. Chromium carbide is used as wear coating.
7. Which class of engineering ceramics generally includes lubricant materials?
Explanation: Molybdenum disulfide (MoS2) and tungsten disulfide (WS2) are common sulfide materials used in lubrication. Metalloid elements like germanium and silicon are used as electronic devices. Intermetallics like Nickel aluminide are used in water coatings.
8. Which of the following is a characteristic of alumina?
a) Excellent hardness
b) Good tensile strength
c) Good toughness
d) Poor wear resistance
Explanation: Aluminum oxide (Al2O3) is regarded as the oldest engineering ceramic. They have excellent hardness and wear resistance. They are stiffer and stronger than steels. Their tensile and toughness properties, however, can be improved by mixing them with zirconium.
9. What is the tensile strength of aluminum oxide?
a) 175 MPa
b) 210 MPa
c) 415 MPa
d) 550 MPa
Explanation: Alumina has a medium tensile strength of 210 MPa and Young’s modulus of 3.86 * 105. Silicon carbide has a tensile strength of 175MPa, which is lower than alumina. The tensile strength of silicon nitride and sialons are 415 MPa and 550 MPa respectively.
10. Which among the following exhibits the highest thermal conductivity?
b) Silicon carbide
c) Silicon nitride
Explanation: Silicon carbide (SiC) has a high thermal conductivity of 83.6 W/m/K. It also has the highest Young’s modulus of 4.14 * 105 among the following. The thermal conductivities of alumina, silicon nitride, and sialon are 8.4, 25, and 21.3 W/m/K in that order.
Sanfoundry Global Education & Learning Series – Engineering Materials & Metallurgy.
To practice all areas of Engineering Materials & Metallurgy, here is complete set of 1000+ Multiple Choice Questions and Answers.