Question

5. What is a ceramic? The mechanical al property data for ceramics show a considerable broad range. What is the cause of this scatter in the data? What is the significance of this in engineering practice and how can this scatter in the properties be reduced? (6 points)

Answer 1

Traditional ceramic is inorganic non-metallic material with high strength, high melting point, oxidation resistance, and refractory material. Advanced ceramics in technical applications must satisfy extremely high demands in terms of their properties.

Ceramic material having different properties based on their atomic structure and composition and also their application

Let’s see the property-

• Property # 1: Physical property
• Property # 2: Mechanical property
• Property #3: Electrical property
• Property #4: Thermal property
• Property # 5: Magnetic property
• Property # 6: Chemical Property
• Property # 7: Dielectric property

Ceramic all basic property

  Property # 1: Physical Property

Physical properties are based on its crystal structure and chemical composition. Generally, Physical properties are identified by simple methods such as odor, color and physical form of the material (solid, liquid, gas). Other physical properties of ceramics are

Physical properties are based by its crystal structure, chemical composition and physical form of the ceramic-like solid, liquid and gas form also it depends upon the odor, color, and structure.

In physical property, we consider the volume, density, heat capacity, melting and boiling point, the porosity of that material. these are a very important parameter of ceramic material

Physical property include that 3 main category

• Density: Ceramics are intermediate in density between polymers (lower) and metals (higher) in the range of 2-6 gms/cm3. Non-crystalline materials are less dense than crystalline ones. Compositions with several ALLOTROPES such as SiO2 will have minor differences in density.

• Melting and Boiling Point: Ceramic having high melting point i.e. 600-4000C and also thermal conductivity is low and the value of thermal expansion are 1-15 ppm/C

• Colour:  Depends on visible light interaction with “ions” or “pigments” (Color from ions [typically 0.2-0.4%] depends on the oxidation state)

  Property # 2: Mechanical Property

Mechanical properties generally describe the strength of the material. It is important in structural and building materials.

The mechanical property of mainly describe two main things i.e.

• Hardness: Evaluating hardness homes depends heavily on the test technique. Knoop hardness is usually used for difficult, brittle substances. It uses a diamond-shaped tool to make a measurable impact on the cloth with a standardized load.

• Flexural Strength: Flexural strength is the effective power of a material under a bending load. The test takes under consideration grain shape and defects within the material and is typically performed on brittle substances. Evaluating flexural strength famous a cloth’s sturdiness as it takes under consideration both compressive and tensile strengths.

Property #3: Electrical Property

Electrical properties are related to how easily electrical energy passes through a material. Electricity effects of the ceramic material application that they used ceramic. The electrical properties of ceramic substrates perform an important task in the operation of electronic circuits.

The main consideration in electrical property are dielectric strength and resistivity

• Dielectric Strength: it is how a good deal electric ability, or voltage, a cloth can hold lower back before breaking down. Eventually, the voltage will become too much, and the material breaks right down to allow the electricity through.
• Electrical Resistivity: The electrical resistivity of a material is a measure of its ability to transport charge under the influence of an applied electric field.

Property #4: Thermal property

Thermal property means the ceramic material reacts to the change in temperature .in thermal properties of ceramic it mainly consists of two main parts i.e. thermal conductivity and coefficient of thermal expansion

• Thermal Conductivity: It measures how well a fabric spreads warmness within itself. Cooking pans have high thermal conductivity permitting calmly distributed heat to pass speedily into the meals. On the opposite hand, insulative gloves are used to address warm objects because their low thermal conductivity prevents warmth from transmitting to sensitive arms.
• Coefficient of Thermal Expansion: On heating, ceramics expand this is generally known as thermal expansion. Thermal expansion is due to the conduction of heat. It defines how a whole lot a fabric expands based on outside temperatures. Most substances swell with the utility of warmth because the power reasons the atoms to move more hastily, stretching their bonds. Ceramics commonly have a low coefficient because of their sturdy interatomic bonds.

  Property # 5: Magnetic Property

The magnetic property of any can be defined by how to respond to the material in the magnetic field. ceramic are refractory material hence they can’t respond for any magnetic field

Property # 6: Chemical Property

Ceramics are bonded together by an ionic or covalent bond. Basically, these bonds result in good chemical resistance but have low thermal expansion, high melting point, and hardness.

Ceramics are chemically inert, allowing them to be used in programs that cause different substances to degrade.

  Property # 7: Dielectric Property

Dielectric properties are directly related to piezoelectric properties. The dielectric constant, which is the ratio of the permittivity of the material to its permittivity to free space, is an indicator of how the material concentrates on electric flux.

Because they can temporarily store electric energy dielectric ceramics serve an important role as a material for manufacturing capacitors, which, in turn, are responsible for properly supplying electric energy and signals to circuits