Ceramics: An introduction
Ceramics are encountered in virtually -every facet of industry and everyday life. An understanding of what a ceramic is and what it can do significantly broadens the scope and effectiveness of an engineer, technician or instructor. Ceramic materials have become increasingly important in modern industrial and consumer technology, yet most engineers and technologists receive little or no information in ceramics and are ware to take advantage of their unique properties.
Definition & Chemistry Type
Ceramics can be defined as inorganic, non-metallic materials that are typically produced using clays and other minerals from the earth or chemically processed powders. Ceramics are typically crystalline in nature and are compounds formed between metallic and non-metallic elements such as aluminium and oxygen (alumina, silicon and nitrogen icon nitride, silicon and carbon, etc.
Scope of Ceramics
Most of us when hear the word ceramics, think of art, dinnerware, pottery, tiles, brick and toilets. These products are commonly referred to as traditional silicate-based ceramics. While these traditional products have been and continue to be important to the society, a new class of ceramics has emerged - that most people are not aware of. These advanced or technical or modern or industrial ceramics are being used for applications such as space shuttle tile, engine components, artificial bones and teeth, computers and other electronic components and cutting tools, just to name a few.
Role of Ceramics in Modern World
Since ancient times, the technology and applications of ceramics (including glass) have steadily increased. We often take for granted the major role that ceramics have played in the progress of humankind. Lets look at a few examples of the importance of ceramics in our lives. Just a few questions one may ask oneself, before we uncover the role of Ceramics in modem world.
Can we imagine a world without Steel?
Can we imagine a world without Buildings?
Can we imagine a world without Electricity?
Can we imagine a world without Glass?
Can we imagine a world without Electronics?
Can we imagine a world without Telecommunications?
Can we imagine our body without Bones?
As our body cant stand without bones, no modern world nation can stand without Ceramics.
And even when we imagine the other world, can it be possible to travel there without a space shuttle (duly protected by Ceramic light weight thermal barrier tile)? Let us review the major role of Modern Ceramics to various industries to understand its importance to a modern world nation.
We do not have to imagine a world without Steel, thanks to (Ceramic) Refractories: modern iron, steel and non-ferrous metal production would not be possible without the use of sophisticated refractory materials that are used to line high temperature furnaces, channels and ladles. Metals make automobiles, machinery, planes, buildings and thousands of other useful things possible.
We do not have to imagine a world without Buildings, thanks to (Ceramic) brick, cement, tile and glass: much of the construction industry depends on the use of ceramic materials. This includes brick, cement, tile and glass. Cement is used to make concrete which in turn is used for roadways, dams, buildings and bridges. Uses of glass in the construction industry include various types of windows, glass block and fibres for use in insulation, ceiling panels and roofing tiles. Brick is used for homes and commercial buildings because of its strength, durability and beauty. Brick is the only building product that will not burn, melt, dent, peel, warp, rot, rust or be eaten by termites. Tile is used in applications such as flooring, walls, countertops and Fireplaces. Tile is also a very durable and hygienic construction product that adds beauty to any application.
We do not have to imagine a world without Electricity, thanks to (Ceramic) high-tension insulators: ceramics are excellent insulators. High voltage insulators make it possible to safely carry electricity to houses and businesses.
We do not have to imagine a world without Glass, thanks to (Ceramic) refractories: refractory ceramics are enabling materials for the glass industry and other industries as well. The chemical, petroleum, energy conversion and other ceramic industries all rely on refractory materials.
We do not have to imagine a world without Electronics, thanks to (Ceramic) semiconductors, superconductors and magnets: the electronic industry would not exist without ceramics. Ceramics can be excellent insulators, semiconductors, superconductors and magnets. Its hard to imagine not having mobile phones, computers, television and other consumer electronic products.
We do not have to imagine a world without Telecommunications, thanks to (Ceramic) silica fibres: fibre optic fibres have provided a technological break- through in the area of telecommunications. Information that was once carried electrically through hundreds of copper wires is now being carried through high- quality transparent silica (glass) fibres. Use of this technology has increased the speed and volume of information that can be carried by orders of magnitude over that which is possible using copper cable. The reliability of the transmitted information is also greatly improved with fibre optic fibres. In addition to these benefits, the negative effects of copper mining on the environment are reduced with the use of silica fibres.
We do not have to imagine our body without Bones, thanks to (Ceramic) artificial bones: Orthopaedics has advanced greatly with the aid of Ceramic artificial bones. Surgeons are already using bioceramic materials for repair and replacement of human hips. Knees, shoulders, elbows, fingers, eyes and wrists. Ceramics are also being used to replace diseased heart valves. Dentists are using ceramics for tooth replacement implants.
Role of Ceramics in Pollution Control
After all these human gestures of innovations, when the nature gets polluted - again ceramics comes in role in controlling the pollution. Ceramics play an important role in addressing various environmental needs. Ceramics help decrease pollution, capture toxic materials and encapsulate nuclear waste. Todays catalytic converters in vehicles are made of cellular ceramics and help convert noxious hydrocarbons and carbon monoxide gases into non- toxic carbon dioxide and water. Advanced ceramic components are starting to be used in diesel and automotive engines. Ceramics properties like - light weight, high-temperature resistance and wear resistance results in more efficient combustion and significant fuel savings.
Advantages Over Metals:
Besides their ability to withstand elevated temperatures, modern ceramic have many other advantages over metals.
-Ceramics are usually lighter than metals, sometimes weighing; only about 40 % as much. This is important in aircraft missile and spacecraft applications, where reduced weigh conserves fuel. In a gas turbine engine, a lightweight ceramic rotor accelerates more rapidly than a heavier metallic rotor because it has les inertia.
-They are highly resistant to oxidation and other chemical glue, as well as to corrosion.
-Because of their high temperature resistance, ceramics may prevent the need for cooling equipment, especially in diesel engines.
-Some ceramics are exceptionally hard. The hardest substance known, such as diamond, boron carbide, cubic boron nitride and silicon carbide are ceramics. They can be excellent cutting agents.
-Because of their low coefficient of friction, high compressive strength and wear resistance, some ceramics can be used in bearings and other mechanical parts without requiring lubrication.
- Some modern ceramics can withstand temperatures as high as 1600 degree C, whereas even the best super-alloys can seldom be used above about 1100 C.
Modern ceramics are potentially less expensive than super-alloys. In the years ahead, these ceramics are expected to be much cheaper than super-alloys. Unlike super-alloys ceramics (not require the increasingly expensive strategic metals (viz cobalt, chromium, nickel and tungsten) for high temperature use.