Ceramics MCQ Quiz - Objective Question with Answer for Ceramics - Download Free PDF

Explanation:

Advanced Ceramics

Definition: Advanced ceramics, also known as technical ceramics or engineered ceramics, are a class of materials that exhibit superior mechanical, thermal, electrical, and chemical properties compared to conventional ceramics. These materials are designed for high-performance applications in industries such as aerospace, electronics, automotive, medical devices, and energy. Advanced ceramics are typically made from compounds like oxides, nitrides, carbides, and borides.

Correct Option Analysis:

The correct option is:

Option 2: Nitrides

Nitrides, such as silicon nitride (Si₃N₄), aluminum nitride (AlN), and titanium nitride (TiN), are examples of advanced ceramics. These materials are engineered to possess unique properties, including high temperature resistance, excellent mechanical strength, thermal conductivity, electrical insulation, and chemical stability. These characteristics make nitrides suitable for demanding applications such as cutting tools, turbine components, electronic substrates, and protective coatings.

Examples and Applications:

• Silicon Nitride (Si₃N₄): Used in ball bearings, engine components, and turbine blades due to its high fracture toughness, low thermal expansion, and resistance to high temperatures.
• Aluminum Nitride (AlN): Commonly used in electronics as a substrate material for integrated circuits and heat sinks, owing to its excellent thermal conductivity and electrical insulation properties.
• Titanium Nitride (TiN): Utilized as a hard coating for cutting tools and wear-resistant surfaces due to its exceptional hardness and corrosion resistance.

Advantages of Nitrides:

• High mechanical strength and hardness.
• Excellent thermal and electrical properties.
• Resistance to wear, corrosion, and oxidation.
• Ability to withstand extreme temperatures and harsh environments.

Disadvantages of Nitrides:

• Relatively high production costs compared to conventional ceramics.
• Complex manufacturing processes requiring advanced techniques like sintering and hot pressing.

Conclusion:

Nitrides represent a significant category within advanced ceramics due to their exceptional properties and wide-ranging applications. They are indispensable in industries that require materials capable of performing in extreme conditions while maintaining reliability and durability.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: Cement

Cement is a conventional ceramic material used primarily in construction. It is made from limestone, clay, and other raw materials that are processed to form a binder for concrete and mortar. While cement is an important material, it does not fall under the category of advanced ceramics due to its relatively lower performance characteristics in terms of mechanical strength, thermal stability, and chemical resistance.

Option 3: Clay Products

Clay products, such as bricks, tiles, and pottery, are examples of traditional ceramics. These materials are typically made from natural clay and are used in construction, art, and household applications. Clay products lack the high-performance properties of advanced ceramics and are not suitable for demanding industrial applications.

Option 4: Silicate Glass

Silicate glass is a type of conventional ceramic material made from silica (SiO₂) and other additives. It is widely used in windows, containers, and optical applications. Although silicate glass possesses good transparency and chemical stability, it does not exhibit the advanced mechanical, thermal, and electrical properties characteristic of advanced ceramics like nitrides.

Conclusion:

Advanced ceramics, such as nitrides, are specifically engineered for high-performance applications requiring superior properties. The other options, including cement, clay products, and silicate glass, represent conventional ceramics that lack the specialized characteristics of advanced ceramics. Understanding the distinction between traditional and advanced ceramics is crucial for identifying materials suitable for specific industrial and technological applications.

Ceramics

A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature.

Common examples are earthenware, porcelain, silicate glass, and brick.

Properties of ceramics

• High hardness
• High melting point
• Good Thermal insulator
• Highly electricity resistance
• Low mass density
• Generally, chemically inert
• Brittle in nature
• Zero ductility
• Low tensile strength​

Advantages of ceramics

• Most of them have high hardness hence they are used as abrasive powder and cutting tools
• They have a high melting point which makes them excellent refractory material
• They are good thermal insulators this is another reason to use them as refractory material
• They are high electric resistivity which makes them suitable to be used as an insulator
• They have a low mass density which results in lightweight components
• They are generally chemically inert which makes them durable

• Theoretically, the tensile strength of ceramics is very high but in practice,it is quite low.
• Tensile failures of ceramics are attributed to the stress concentrations at the pores and micro-cracks at grain corners.
• The modulus of elasticity ranges from 7 × 10⁴ to 42 × 10⁴ N/mm²
• Glass fiber's tensile strength of the order of 700 N/mm²

Compressive strength:

• The compressive strength is high and it is usual to use ceramics like clay, cement, and glass products in compression.

Shear strength:

• Ceramics have very high shear strength with resistance to failing in a brittle manner

Transverse strength:

• It is difficult to ascertain and ceramics are not used in the places where such strength is the criteria.

Explanation:

Ceramic Properties

• The properties of ceramic materials, like all materials, are dictated by the types of atoms present, the types of bonding between the atoms, and the way the atoms are packed together.
• The atoms in ceramic materials are held together by a chemical bond.
• The two most common chemical bonds for ceramic materials are covalent and ionic.
• For metals, the chemical bond is called the metallic bond.
• The bonding of atoms together is much stronger in covalent and ionic bonding than in metallic. That is why, generally speaking, metals are ductile and ceramics are brittle.
• Due to ceramic material's wide range of properties, they are used for a multitude of applications.
• In general, most ceramics are:
  • hard
  • wear-resistant
  • brittle
  • refractory
  • thermal insulators
  • electrical insulators
  • nonmagnetic
  • oxidation resistant
  • prone to thermal shock
  • chemically stable

Ceramic materials:

• Ceramics are compounds between metallic and non-metallic elements.
• They are more frequently nitrides, oxides, carbides.
• They are hard & brittle.
• Examples are Mgo, Cds, Al2O3, SiC, BaJiO3, Silica, Soda-lime glass, concrete, cement, ferrites, garnets, some supper conductors.

Metal atoms have outer electrons which are not tied to any one atom.

These electrons can move freely within the structure of a metal when an electric current is applied.

Hence metals are good conductors of heat and electricity. 

Pure metals reflect light but do not transmit it, because they are filled with free electrons. Hence they are not transparent to visible light. 

Ceramics

A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature.

Common examples are earthenware, porcelain, silicate glass, and brick.

Properties of ceramics

• High hardness
• High melting point
• Good Thermal insulator
• Highly electricity resistance
• Low mass density
• Generally, chemically inert
• Brittle in nature
• Zero ductility
• Low tensile strength​

Advantages of ceramics

• Most of them have high hardness hence they are used as abrasive powder and cutting tools
• They have a high melting point which makes them excellent refractory material
• They are good thermal insulators this is another reason to use them as refractory material
• They are high electric resistivity which makes them suitable to be used as an insulator
• They have a low mass density which results in lightweight components
• They are generally chemically inert which makes them durable

• Theoretically, the tensile strength of ceramics is very high but in practice,it is quite low.
• Tensile failures of ceramics are attributed to the stress concentrations at the pores and micro-cracks at grain corners.
• The modulus of elasticity ranges from 7 × 10⁴ to 42 × 10⁴ N/mm²
• Glass fiber's tensile strength of the order of 700 N/mm²

Compressive strength:

• The compressive strength is high and it is usual to use ceramics like clay, cement, and glass products in compression.

Shear strength:

• Ceramics have very high shear strength with resistance to failing in a brittle manner

Transverse strength:

• It is difficult to ascertain and ceramics are not used in the places where such strength is the criteria.

• Ceramic materials are inorganic and non-metallic materials.
• Ceramic materials are relatively stiff and strong.
• These are insulative to both heat and electricity. 
• Ceramic materials are brittle, hard, strong in compression, and weak in shearing and tension.
• Some of the most common ceramics are aluminum oxide, silicon dioxide, silicon carbide, earthenware, porcelain, and brick, etc.

Explanation:

Ceramic Properties

• The properties of ceramic materials, like all materials, are dictated by the types of atoms present, the types of bonding between the atoms, and the way the atoms are packed together.
• The atoms in ceramic materials are held together by a chemical bond.
• The two most common chemical bonds for ceramic materials are covalent and ionic.
• For metals, the chemical bond is called the metallic bond.
• The bonding of atoms together is much stronger in covalent and ionic bonding than in metallic. That is why, generally speaking, metals are ductile and ceramics are brittle.
• Due to ceramic material's wide range of properties, they are used for a multitude of applications.
• In general, most ceramics are:
  • hard
  • wear-resistant
  • brittle
  • refractory
  • thermal insulators
  • electrical insulators
  • nonmagnetic
  • oxidation resistant
  • prone to thermal shock
  • chemically stable

Piezoelectricity:

Piezoelectricity is the electric charge that accumulates in certain solid materials (such as crystals, certain ceramics, and biological matter such as bone, DNA and various proteins) in response to applied mechanical stress.

The word piezoelectricity means electricity resulting from pressure and latent heat.

Piezoelectric ceramics:

Barium titanate (BaTiO₃) - The first piezoelectric ceramic discovered.

Lead titanate (PbTiO₃)

Lead zirconate titanate (PZT) - Currently the most commonly used piezoelectric ceramic.

Potassium niobate (KNbO₃)

Lithium niobate (LiNbO₃)

Lithium tantalate (LiTaO₃)

Ceramics:

• These are the compound between metallic and nonmetallic elements.
• Ceramic materials are relatively stiff and strong.
• These are insulative to both heat and electricity, most common ceramics are aluminum oxide, silicon dioxide, silicon carbide Mica, etc.
• Mica is a naturally occurring non-metallic mineral that is based on a collection of silicates.
• Mica is a very good insulator that has a wide range of applications in the electrical and electronics industry.
• It possesses resistance to a sudden change in temperature and can withstand high voltage.

A substance can be divided into four types based on the conductivity of the electricity:

Insulator:

• The substances that not allow the current to flow through them.
• They don't have any free electrons.
• Example - Cotton, Wood, Glass, ceramics, etc.

Conductors:

• The substances that allow the current to flow through them are known as conductors.
• They have a large number of free electrons.
• Example - Copper, Silver, Iron, Aluminium, etc.

Superconductors:

• This substance has zero resistance at a very low temperature.
• So electricity flows through them rapidly.​
• Example- Mercury below 4.2 K, Lead below 7.25 K acts like superconductors. (K= kelvin)

Semiconductors:

• Some substances that have electrical resistivity between those of conductors and insulators,
• Example - Silicon and germanium. 

All three statement are correct.

Explanation:

Ceramic Properties

• The properties of ceramic materials, like all materials, are dictated by the types of atoms present, the types of bonding between the atoms, and the way the atoms are packed together.
• The atoms in ceramic materials are held together by a chemical bond.
• The two most common chemical bonds for ceramic materials are covalent and ionic.
• For metals, the chemical bond is called the metallic bond.
• The bonding of atoms together is much stronger in covalent and ionic bonding than in metallic. That is why, generally speaking, metals are ductile and ceramics are brittle.
• Due to ceramic materials wide range of properties, they are used for a multitude of applications.
• In general, most ceramics are:
  • hard
  • wear-resistant
  • brittle
  • refractory
  • thermal insulators
  • electrical insulators
  • nonmagnetic
  • oxidation resistant
  • prone to thermal shock
  • chemically stable

Explanation:

Fibre reinforced composite(FRP): 

• These materials consist of fibres of significant strength and stiffness embedded in a matrix with distinct boundaries between them.
• Both fibres and matrix maintain their physical and chemical identities, yet their combination performs a function which cannot be done by each constituent acting singly. It appears obvious that FRP having continuous fibres is indeed more efficient.

According to the matrix used these are

• Polymer matrix composites: these are made of thermoplastic or thermoset resins reinforced with fibres such as glass, carbon or boron and matrix as Epoxy Polyimide, Polyester Thermoplastics & Polysulfone.
• Metal matrix composites: consist of a matrix of metals or alloys reinforced with metal fibres such as boron or carbon and matrix as Aluminium, Magnesium, Titanium & Copper
• Ceramic matrix composites: consist of ceramic matrices reinforced with ceramic fibres such as silicon carbide, alumina or silicon nitride. They are mainly effective for high-temperature applications. Matrix used are Silicon carbide, Alumina, Glass-ceramic & Silicon nitride
• Carbon/carbon composites: consist of graphite carbon matrix reinforced with graphite fibres and matrix used is Carbon. In addition to the above, there are other types of composites as well. The flake composites consist of a matrix reinforced with flakes which may be of different types such as glass flakes, mica flakes and metal flakes. The distribution of the flakes throughout the matrix provides a considerable barrier to moisture, gas and chemical transport. It can suitably be used for obtaining high thermal and electrical resistance or conductivity.

Electrical properties of ceramic materials include:

• Very high electrical resistance at a low temperature which results in low conductivity and it, therefore, behaves as an insulator i.e. non-conductor.
• High dielectric constant
• High dielectric strength
• Low dielectric loss

Hence, option 3 is correct. 

Explanation:

Traditional ceramics: 

• These are usually based on clay and silica. There is sometimes a tendency to equate traditional ceramics with low technology, however, advanced manufacturing techniques are often used.
• Competition among producers has caused processing to become more efficient and cost-effective. Complex tooling and machinery is often used and may be coupled with computer-assisted process control. These include high-volume items such as bricks and tiles, toilet bowls (whitewares), and pottery. Their major component is silicon carbide. 

Advanced ceramics:

• These are also referred to as engineering ceramics. They exhibit superior mechanical properties, corrosion/oxidation resistance, or electrical, optical, and/or magnetic properties. These include newer materials such as laser host materials, piezoelectric ceramics, ceramics for dynamic random access memories (DRAMs), etc., often produced in small quantities with higher prices. Alumina, Titanium carbide and tungsten carbide are some example of these.