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![Piezoelectric ceramics
♦
Piezoelectricity is a property of certain classes of crystalline
materials including Barium Titanate BaTiO3 and Lead
Zirconate Titanates Pb[ZrxTi1-x]O3(PZT)
.
.
♦
When mechanical pressure is applied to one of these materials,
the crystalline structure produces a voltage proportional to
the pressure. Conversely, when an electric field is applied, the
structure changes shape producing dimensional changes in
the material
.
♦
Use as sensors , actuators and transducers
.](https://image.slidesharecdn.com/advancedceramics-240821192548-2e02c0f1/85/Advanced-Ceramics-for-different-applications-pptx-7-320.jpg)
![Magnetic ceramics
♦
Magnetic ceramics are made of ferrites, which are
crystalline minerals composed of iron oxide in
combination with some other metal. They are given
the general chemical formula M(FexOy), M
representing other metallic elements than iron. The
most familiar ferrite is magnetite, a naturally occurring
ferrous ferrite (Fe[Fe2O4], or Fe3O4) commonly known as
lodestone
.
Ceramic Magnets](https://image.slidesharecdn.com/advancedceramics-240821192548-2e02c0f1/85/Advanced-Ceramics-for-different-applications-pptx-8-320.jpg)
Advanced Ceramics for different applications.pptx
- 1.
- 2. Advanced Ceramics ♦ Advanced ceramicsare ideally suited for industrial applications hat provide a physical interface between different components due to their ability to withstand high temperatures, vibration and mechanical shock . ♦ A type of ceramic exhibiting a high degree of industrial efficiency . ♦ A type of ceramic used in specialized, recently developed applications . ♦ Advanced ceramics often have simple chemical compositions, but they are difficult to manufacture .
- 3. Classification of Advancedceramics Advanced Ceramics Conducting ceramics Structural Ceramics Electronic substrate Ceramic dielectric, piezoelectric Ceramics Magnetic ceramics Electro- ceramics Optical ceramics Automotive Ceramics Aerospace Ceramics Wear resistance Ceramics Cutting tools Bio-Ceramics
- 4. Electroceramics ♦ Is a classof ceramic materials used primarily for their electrical properties . ♦ It includes materials for a wide range of applications (power conversion and storage, communications and electronics) . ♦ The materials for such applications are usually prepared from specifically formulated compositions (typically not found in nature), and processed under strictly controlled conditions . ♦ Further classified to :
- 5. Electronic substrate ♦ Substrate (alsocalled a wafer) is a solid (usually planar) substance onto which a layer of another substance is applied . ♦ An insulator such as silicon oxide or aluminum oxide is used as the substrate . ♦ The advantage of substrate is that the oxide layer can provide superior insulation between adjacent materials .
- 6. Dielectric Ceramics ♦ Dielectric materialsare capable of storing large amounts of electrical charge in relatively small volumes . ♦ Is an electrical insulator that can be polarized by an applied electric field . ♦ Dielectric materials can be solids, liquids, or gases . ♦ Solid dielectrics are perhaps the most commonly used dielectrics in electrical engineering . .
- 7. Piezoelectric ceramics ♦ Piezoelectricity isa property of certain classes of crystalline materials including Barium Titanate BaTiO3 and Lead Zirconate Titanates Pb[ZrxTi1-x]O3(PZT) . . ♦ When mechanical pressure is applied to one of these materials, the crystalline structure produces a voltage proportional to the pressure. Conversely, when an electric field is applied, the structure changes shape producing dimensional changes in the material . ♦ Use as sensors , actuators and transducers .
- 8. Magnetic ceramics ♦ Magnetic ceramicsare made of ferrites, which are crystalline minerals composed of iron oxide in combination with some other metal. They are given the general chemical formula M(FexOy), M representing other metallic elements than iron. The most familiar ferrite is magnetite, a naturally occurring ferrous ferrite (Fe[Fe2O4], or Fe3O4) commonly known as lodestone . Ceramic Magnets
- 9. Optical ceramics ♦ Optical ceramicsare polycrystalline materials produced through controlled crystallization of base glass . ♦ It share many properties with both glasses and ceramics . ♦ Optical ceramics have an amorphous phase and one or more crystalline phases and are produced by a so- called "controlled crystallization" in contrast to a spontaneous crystallization, which is usually not wanted in glass manufacturing . ♦ It has a variety of properties such as, high strength, toughness, transparency, opalescence, low thermal expansion, high temperature stability . .
- 10. Structural Ceramics ♦ Ceramic materialsthat demonstrate enhanced mechanical properties under demanding conditions. Because they serve as structural members, often being subjected to mechanical loading, they are given the name structural ceramics . . ♦ Ordinarily, for structural applications ceramics tend to be expensive replacements for other materials, such as metals, polymers, and composites . . ♦ Further classified to :
- 11. Automotive Ceramics ♦ Automotive ceramicsare materials that are made into components for automobiles. Examples include spark plug insulators, catalysts and catalyst supports for emission control devices, and sensors of various kinds . ♦ Its powerful physical, thermal and electrical properties make it a reliable, highly durable and cost-effective alternative to metal. As the industry faces continued pressure to deliver innovative design, improved safety features and environment-friendly vehicles (while also reducing production costs) . Spark Plug
- 12. Aerospace Ceramics ♦ Aerospace ceramicsare ceramic materials that used in commercial, military aircraft and space shuttles . ♦ These materials are generally lighter than metals and thus, have a low mass, which make them highly appealing to the aerospace industry . ♦ are used in aerospace as Thermal Barrier Coatings (TBCs) in the hot part of the engine .
- 13. Wear resistance Ceramics ♦ Wear-resistantceramics are ceramic materials that are resistant to friction and wear. They are employed in a variety of industrial and domestic applications, including mineral processing and metallurgy . ♦ They are being used today in diverse applications such as tips for ball-point pens, precision instrument bearings .
- 14. Cutting tools Ceramics ♦ Theyretain their hardness at high temperatures and have a relatively low reactivity with steel. Hence they can be used at high cutting speeds without deformation . ♦ In recent years there have been significant developments in ceramic tool materials; there are three categories available, namely pure oxide ceramic, mixed oxide plus carbide & nitride and silicon nitride based material .
- 15. Bio-Ceramics ♦ Ceramic products orcomponents employed in medical and dental applications, mainly as implants and replacements . ♦ Bio-ceramic materials are commonly bio-inert materials, (such as Oxide ceramics, Silica ceramics, Carbon fiber) are non- toxic and non-inflammatory. These materials must be long lasting, structural failure resistant, and corrosion resistant .
- 16. Bio-Ceramics ♦ Ceramics are nowcommonly used in the medical fields as dental, and bone implants. Artificial teeth, and bones are relatively commonplace. Surgical cermets are used regularly. Joint replacements are commonly coated with bio-ceramic materials to reduce wear and inflammatory response . Head of a Hip Prosthesis Hip Prosthesis
- 17. Classification of AdvancedCeramics based on compositions ♦ Nitride Ceramics ♦ Used in ceramics consist of nitrogen atoms bonded to elements such as silicon and aluminum . .
- 18. Silicate Ceramics ♦ Silicates arematerials composed generally of silicon and oxygen. Silicate ceramic components are used in electronics and electrical engineering and act as electrical insulation in fuses, circuit breakers, thermostats . ♦ The ability of silicate ceramic materials to provide thermal insulation is also utilized in heating, environmental and thermal engineering applications .
- 19. Carbide Ceramics ♦ Carbide ceramicsare extremely resistant against high temperature, abrasion and corrosion. They are mainly used in mechanical engineering, chemical, and power engineering, microelectronics as well as space engineering .
- 20. Oxide Ceramics ♦ An oxideis a chemical compound made up of oxygen combined with at least one other element. Most of the Earth’s crust consists of oxides .
- 21. Advanced ceramics VsTraditional Ceramics Raw minerals • Clay • Silica • Feldspar Chemically prepared powders Precipitation, spray drying Light microscopy, X-ray diffraction, electron microscopy, neutron diffraction Visible examination, light microscopy Use in high technology devices and modern application Use in classical application such as pottery, building bricks and glass Uses
- 22. Raw materials oftraditional ceramics ♦ The traditional ceramics industry is largely based on various combinations of clay minerals, feldspar and silica . ♦ The mineral raw materials used in the ceramic industry are mainly inorganic, nonmetallic, crystalline solids formed by complex geological processes . ♦ Oxygen, silicon, and aluminum together account for 90% of the elements in the earth’s crust , These, together with other minerals compounds of oxygen, constitute the greatest bulk of naturally occurring ceramic raw materials .
- 23. Eight Elements thatmake up over 98% of Earth’s Crust - Oxygen (O) - Silicon (Si) - Aluminum (Al) - Iron (Fe) - Calcium (Ca) - Sodium (Na) - Potassium (K) - Magnesium (Mg)
- 24. Field of interestfor clay
- 25. Defination of clay ♦ Definitionof clay depends on discipline : • Geologist: grain size <2mm • Engineer: property of plasticity • Ceramicist: hardening on firing • No chemical definition, but: Most clays are high in aluminum • General: a naturally occurring material composed primarily of fine- grained minerals normally (<2mm) fraction of rocks and soils, which is generally plastic at appropriate water contents and will harden when dried or fired .
- 26. Origin and natureof clay How is clay formed 1 . Melted rock is cooled and solidified into igneous rock (mother rock) which makes up earth’s crust . 2 . Weathering over millions of years breaks down the rock from boulders into stones, to pebbles to fine, small particles . 3 . Erosion aids in moving particles away from the site of origin resulting in clay deposits .
- 27. Origin and natureof clay
- 28. Types of Weathering ♦ Thereare two types of weathering
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- 36. Types of ChemicalWeathering
- 37. Types of ChemicalWeathering
- 38. Types of ChemicalWeathering
- 39. Types of ChemicalWeathering
- 40. Types of ChemicalWeathering
- 41. Common types ofclay ♦ Porcelain clay (china clay), which is approximately pure kaolin, this burns to white or light-cream color . ♦ Plastic clay, which contain more impurities than the porcelain clay it burn to yellow-red color and is used for ordinary earthenware . ♦ Fire clay, these clays approach very close to the porcelain clays in composition however they contain a larger quantity of iron, also more silica and is used for building brick .
- 42. Importance charactersitics ofclay ♦ Clays have the ability to form clay-water composition and to maintain their shape and strength during drying and firing . ♦ They fuse over a temperature range depending on their composition in such a way as to become dense and strong without losing their shape .