Properties and Applications of Ceramics, Fibres and Plastic - Assignment Example

Properties and Applications of Ceramics, Fibres and Plastic Ceramics The term ceramic was originated from the Greek word keramikos, which means burnt stuff. This also tells us that the ceramic materials are manufactured through high heating temperature process, also known as firing. Ceramic materials are inorganic and nonmetallic materials. They belong to the class of materials called oxidant ceramics. Mostly ceramic are compounded between metallic and non-metallic elements with interatomic bonds. They are either totally ionic or predominantly ionic. But they also have some covalent characteristics. Ceramic materials are formed by closed packed crystals of oxides of aluminum or zirconium metals. The basic arrangement of these crystals and the presence of impurities determine the resulting material. The final product has slightly different characteristics. Different Ceramic Materials Following are the five different ceramic materials:- Medical grade ceramic Alumina ceramic Ceramic Pottery Ceramic Tiles Ceramic Braces 1. MEDICAL GRADE CERAMIC Composition: Medical grade ceramics are slid materials composed of pure crystals of aluminum or zirconium oxides. These ceramics are not chemically and biologically reactive (inert) to all materials. Properties: They are stiff, strong and hard in properties. They are resistant to scratches. Ceramics attracts fluids on their surface as they have low frictional resistance. The main disadvantage of medical ceramic materials is that they are fragile. They are resistant to heat. They are able to with stand the heat and retain their shape when subjected to intense heat. However, when the limit of stress exceeds, the ceramic material bursts and explodes into many splinters. Application: Two main types of ceramic materials used in modern ceramic total hip are alumina ceramic and zirconia ceramic. Both these materials have their own advantages and disadvantages. 2. ALUMINA CERAMIC Composition: This is made up of small crystals of aluminum oxide. The impurities within alumina ceramic are less than 0.5% in the material’s volume. The modern ceramic crystals of the aluminum oxide are relatively tiny and densely packed together. This type of close packing of aluminum oxide crystals is achieved through applying Hot Is-static Pressures. The ceramic component is re-heated, and then subjected to intense symmetric pressures. Properties: Most ceramics today are tough and hard. The final product’s strength is dependent on the size of the crystals. The smaller the crystals the purer the materials tend to be. The impurities make the ceramics weak and prone to fracture cracks. The coarse structure and the impurities are the cause of the frequent fractures in the old ceramic components. Application: The modern Alumina ceramic balls are extremely tough in their structure. They are tougher than the metallic stem on which they based. Alumina ceramic ball has the ability to sustain 60 times the weight of the average patient. This is one big reason why it is often used in hospitals. . 3. Ceramic Pottery Composition: This is made through coarse aluminum oxide crystals and clay i.e. silica oxide mixed together and heated on fire. They make the bases of commercial ceramic materials for instance the china cups. The name of the group of these materials has been derived from the Greek term “keramos” that means pottery. Properties: They are hard in touch but are easily breakable. Water cannot pass through them. Application: They are heated into different shapes are used as kitchen utensils and for decoration as well. 4. Ceramic Tiles Composition: Tiles are made using clay minerals such as feldspar. Feldspar is used to lower the firing temperature. Once the raw materials have been processed, various steps are taken to obtain the final product. These steps include: 1. Batching 2. Mixing 3. Spray Drying 4. Forming 5. Drying 6. Glazing 7. Firing Properties: The distinct properties of ceramic tiles include rigidness, harness and fragility to sharp ended objects. Application: They are widely used in domestic and office buildings as flooring. 5. Ceramic Braces: missiles. Later those metal braces were replaced by the same material as they were invisible when viewed from normal distance. Properties: Ceramic braces are non-porous and 99.9 percent pure; it is extremely resistant to staining or discoloration. Application: They are soft and comfortable and can be easily removed. They are easy to maintain oral hygiene. Composition: The reason ceramic braces began to focus was because they are less visible. The transparent polycrystalline alumina (TPA) was originally identified by NASA and by a ceramic company called Ceradyne for helping track heat-seeking Fiber Fiber is a class of materials that is either made by continuous filaments or is in discrete elongated pieces. There are many types of man-made fibers. Fiber Optics: Optical fibers are singled, hair-fine filament drawn from molten silica glass. These fibers are now used as replacements of metal wires. Composition: The fiber optic cables are made of optical fibers connected to data links that contain lasers and light detectors. To transmit information data link converts analog electronic signals into the digital pulses of laser light. Then they travel through the optical fiber to another data link, where a light detector reconverts them into an electronic signal. Properties: They are light weighted, durable and transform high speed signals Application: they are widely used for landline telephones services and for broadband nets. Cellulose Fibers Composition: The component cellulose is an organic in nature with the formula (C6H10O5). In industrial uses cellulose is the major constituent of paper, paperboard, and card stock. Properties: Cellulose is odorless and insoluble in water. They are hand, stiff and light weight in nature. Application: in the plastic like forms they are used to create durable items like helmets. Fiberglass Composition: Fiberglass is from a group of products made from individual glass fibers. According to their geometry glass fibers are divided into two major groups: continuous fibers and discontinuous fibers. Continuous fibers are used in yarns and textiles whereas discontinuous which are shot fibers are used as blankets, or boards for insulation and filtration. Properties: they are safe, light weighted and relatively cheap in price. Application: Fiberglass is mostly formed in yarn much like wool or cotton. Fibre-glass textiles are mostly used replacement to molded and laminated plastics as reinforcement agents. It is also used in thermal insulation and sound absorption because of the thick, fluffy material that makes it. Plastic The plastic is a mixture of various components. They include binder plasticizers, pigments, fillers and additives. The binder is the foundation of a plastic. It gives its main characteristic feature as well as it its name. Thus, polyvinyl chloride is both the name for binder and the name of a plastic into which it is made. Properties: The toughness and flexibility of the plastic is induced by adding binders to the plasticizers. There are different types of fillers which are used and added to improve various properties of plastics; for instance their hardness and resistance to shock. Pigments are used to give the plastic its desired color. Distinct properties of plastic include: 1. Hardness 2. Durability 3. Elasticity and Resistance to cold However plastic is not heat resistant. It gets destroyed in heat. Applications: Plastic is widely used in different areas. The plastic is widely used in industrial and domestic usage. Types of Plastic: The two basic types of plastic are thermosetting, and thermoplastic. Thermosetting cannot be reshaped or softened after being subjected to heat and pressure while thermoplastic can be repeatedly softened and remolded by heat and pressure. When heat and pressure are applied over the thermoplastic binder, the chainlike polymers slide past each other. Different types of plastic include Polystyrene and PVC, Nylon and Rubber. MATERIAL PROPERTIES Ceramic Hard Wear-Proof Shinny Electrical Insulators, Nonmagnetic, Resistant To Oxidants Prone To Thermal Shock, Head resistant fragile Fibers Thin Flexible Hard Insoluble to water Light weighted Cheap in price Plastic Not resistant to heat Not resistant to acid Insulator Shinny Insoluble to water References Patrick P. Pizzo, Professor of Materials Engineering (September 26 2010) Ceramics [Online] available from < http://www.engr.sjsu.edu/WofMatE/ceramics.htm > [Accessed 12th Nov, 2010] TOTAL JOINTS .2007.CERAMICS FOR TOTAL JOINTS [Online] [Accessed 12th Nov, 2010] Ceramics – Structure and Properties. available from [Accessed 12th Nov, 2010] Heeger, A. J.; Schrieffer, J. R.; Su, W. -P.; Su, W. 1988. "Solitons in conducting polymers". Reviews of Modern Physics 60: 781. Burroughes, J. H.; Bradley, D. D. C.; Brown, A. R.; Marks, R. N.; MacKay, K.; Friend, R. H.; Burns, P. L.; Holmes, A. B. .1990. "Light-emitting diodes based on conjugated polymers". 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