Answer to Question #199514 in Electrical Engineering for Mary

Question

2. Explain the effects of thermal shock on the behaviour and properties of ceramics

• You should identify specific applications to describe the effects on the ceramic.

• Use relevant diagrams to support your findings.

• Write at least 500 words.

Answer 1

Ceramics derives from the Greek term Queremos, which meaning "potter's clay." However, many substances designated as ceramics now do not include clay.

Modern ceramics can be described as metal and nonmetal composites. Ionic atomic bonding is commonly seen between them.

Insulating materials, glass, refractories, abrasives, and enamels are examples of traditional ceramics.

Metal oxides, carbides, borides, nitrides, and silicates are among them. Tungsten carbide, Silicon carbide, Beryllia, Zirconia, Alumina, and Magnesia are examples.

Because the majority of them have high hardness, they are employed as abrasive powder and cutting tools.

Because of their high melting point, they are good refractory materials.

They are also strong thermal insulators, which is why they are used as a refractory material.

They have high electric resistivity, making them excellent for use as an insulator.

Because of their low mass density, they produce lightweight components.

They have a fragile disposition.

They are practically completely ductile.

Their tensile strength is low.

Even with identical specimens, there is a significant range of variance in strength.

They are challenging to form and manufacture.

Based on their atomic structure, they are classified into two categories.

Ceramics with a crystalline structure

Ceramics that are not crystalline

They can also be divided into three material groups.

Composites of oxides and non-oxides

Ceramic properties

Hardness is quite high.

Extremely high melting point

Thermal insulation of high quality

Electrical resistance is really high.

Mass density is low.

Chemically inert in general Brittle in nature Zero ductility

Tensile strength is low.

Ceramic applications

Because of their lightweight, they are employed in the space industry.

They serve as cutting instruments.

They are refractory materials.

They serve as a thermal insulator.

They serve as electrical insulators.

Ceramics suffer strength deterioration as a result of shock damage when subjected to significant thermal shock. A fracture-damage analysis is provided to investigate the impact of damage on the thermal shock behavior of ceramics. It is believed that following a critical thermal shock, a narrow strip damage zone forms at the tip of an existing crack and that a linear strain-softening constitutive relation may represent the damage behavior. Fracture and damage mechanics are used to predict damage increase and strength deterioration.

The effects of bridging/damage stress, bridging/damage zone fracture energy, and specimen size on thermal shock strength behavior are investigated. Larger fracture energy can improve the residual strength of thermally shocked ceramics, and larger bridging stress is required to decrease strength deterioration for given fracture energy. It is also demonstrated that the thermal shock strength behavior is size-dependent, with a high value of (KIC/Ob)2, where KIC is the intrinsic fracture toughness, and Ob is the bending strength, greatly improving the residual strength.