Depending on the application, the properties of the materials must meet special requirements that go beyond their general performance profile like, for example, high electrical insulation as machine and plant components, as well as high mechanical strength and reliability over long periods. For decades now, in imaging diagnostic processes, for example in angiography as electrically insulating casing components of an X-ray image intensifier, the technical properties of high-grade Al 2 O 3 ceramics have enabled image quality with exceptionally high detail resolution combined with minimized local exposure to radiation for the patient.

In the application of an open magnet resonance imager for surgical interventions, the magnetizability of the instruments used plays an important role. In equipment for therapy with heavy ions, today synchrotrons can be used, which at certain positions of the accelerator ring are equipped with high-vacuum-tight tubes made of Al 2 O 3 ceramics brazed to metal parts. Implant products made of monolithic ceramic materials, for example hip joints, exhibit other properties as a precondition for their usability:.

1. Ceramics in Biology and Medicine.
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5. Bioceramic - Wikipedia.
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For dental applications, aesthetic aspects must also be considered insofar as the visible part of the teeth is concerned. Looking at medical engineering overall, it is foreseeable that the use of products and components made of high-quality technical oxide ceramics and presumably non-oxide ceramics will continue to increase considerably in line with growing life expectancy. Ceramics generally start with a clay-based material dug from the ground that's mixed with water to make it soft and flexible and other materials, squashed into shape, then fired at high-temperature in a large industrial oven called a kiln.

Firing is what most ceramics have in common; the very word "ceramic" originally comes from Sanskrit and means "to burn. Photo: Ceramic tiles get their hardness from being fired.

Although that makes them extremely durable, it also means they're relatively fragile and brittle: they crack quite easily. The US Geological Survey lists six types of clay mined in the United States: common clay, kaolin China clay , bentonite, ball clay, fuller's Earth, and fire clay, and each has a number of different uses:. Each one of these also has numerous different grades and qualities, so it's probably more accurate to talk about China clays or Ball clays in the plural.

Ball clay, for example, is used to make things like fine porcelain tableware and bathroom suites, but even within a single ball clay mine, different grades of clay will be simultaneously excavated from different areas and kept separate or blended in various ways for different end uses.

Ceramics in Biology and Medicine

Before they're fired, raw ceramics can be shaped in all kinds of ways; different manufacturing processes are used for different end products. So pipes, for example, are made by extrusion squeezing clay through a hole, a bit like toothpaste from a tube. Glass is made by blowing, molding, or being floated on top of water the float-glass process by which large, flat windows are made. Bricks, on the other hand, are almost always made in molds to ensure they're a consistent size and shape for stacking into walls. While a great deal of modern pottery is molded, some is still thrown by hand, on a foot-powered wheel, in the traditional way.

Other ceramic processes include pressing squeezing powder into a mold , casting, and jiggering laying raw material into a rotating mold. Advanced engineering ceramics are often made in more advanced ways. For example, the silicon nitride used in cutting tools is made by reaction bonding, in which silicon powder is squashed into shape and heated with nitrogen gas.

Bioceramic - Wikipedia

What's the easiest way to build a house or a wall? With bricks, of course! They're simple to use, inexpensive, attractive to look at, and they can last hundreds of years. Some of the most famous constructions in history have been made from brick, including parts of the Great Wall of China and many of the structures built during the Roman Empire.

Photo: Most bricks are this distinctive red-brown color because of the iron they contain. This brick pattern is an example of what's called runner bond: all the bricks are pointing the same way but the bricks in one course run over the joins in the course beneath. Stone is a natural building material you can use the moment you dig it out of the ground. Bricks, on the other hand, have to be made from clay before we can build with them.

As we've already seen above, clay is a naturally occurring ceramic based on the chemical elements aluminum , silicon, and oxygen. If you've ever dug wet, clay-rich soil, you know it's very thick and sticky. Bricks are popular as building materials for several reasons. First, clay is available throughout the world in large quantities and brickmaking is a fairly simple process, so bricks themselves are relatively inexpensive. Building bricks are much lighter and easier to work with than stone and sometimes last longer.

They're attractive to look at, weatherproof, and—like other ceramics—very good at resisting high temperatures. By using different clays, it's possible to make bricks in different colors.

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Traditional red bricks take their color from iron in their clay, while yellow bricks have a greater quantity of lime or chalk. Brickworks brickmaking plants are built in places where there are large supplies of clay available nearby. The first stage in making bricks involves digging the clay from pits in the ground. Raw clay isn't immediately usable as it is: rocks and other impurities have to be removed first by screening and filtering. The clay is then mixed with water and kneaded in machines that resemble giant food mixers or modern breadmaking machines.

The now-soft clay mixture is squeezed out through a rectangular-shaped hole imagine toothpaste squeezing from a tube with a square-shaped hole in a process called extrusion. Building bricks often have holes bored into them, partly to make them lighter and less expensive but also so the mortar penetrates inside them and holds them more securely. Wires cut the lengths of clay into separate bricks, which are then stacked up on trucks and moved into drying rooms where the moisture they contain is allowed to evaporate over a period of about a day or so. Once that process is complete, the trucks are moved again into giant kilns the ovens that turn the soft clay into hardened bricks ready for building , some of which are over m ft long!

The firing time and temperature vary according to the type of clay being used and the type of end-product required. Although much more efficient, this process—digging the clay, shaping it, and heating it to harden it—is essentially the way bricks have been made for at least years.

Traditionally, bricks were shaped by hand and left to fire in the sun. Sun-dried adobe bricks are still made this way. Refractory bricks also called fire bricks and fireclay bricks are made by a slightly different process. Since they need to withstand much higher temperatures than ordinary building bricks, the clay they're made from is compressed by hydraulic rams to make a much more dense mass, before the bricks are shaped and loaded into the kiln.

That's why refractory bricks and much heavier than ordinary building bricks of roughly the same size.

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Bricks—a closer look What's the easiest way to build a house or a wall? What is brick? There are essentially two kinds of bricks: ordinary building bricks and refractory bricks: Building bricks are made to a standard size typically 20—22cm long, 9—11cm wide, and 5—7cm high approx 8—8. They're made from higher grades of clay and finished on at least one side face so they look attractive on houses and walls. Refractory bricks are made for high-temperature use for lining such things as industrial smokestacks chimneys and household fireplaces, so they tend to be made more crudely and less attractively finished.

Unlike ordinary bricks, they're typically made using such raw minerals as fireclay, alumina aluminum oxide , silica silicon oxide , and dolomite calcium magnesium carbonate. How are bricks made? Campbell and Will Pryce. A fascinating, comprehensive history of how humans have used brick from neolithic times to the present day.

Lavishly illustrated.

Materials in Medicine

John Wiley and Sons, An unusual book that explores the use of brick, as a traditional material, for hard landscaping in gardens and other outdoor areas. Bricks and Brickmaking by Martin Hammond. Shire, A short page booklet explaining why bricks have been so popular for so long. Focuses mainly on British architecture. Nile Valley of Egypt. Mid-late s: Development of effective glass and ceramic insulators for telegraphs and electric power distribution.

Sponsored links. Find out more On this website Composites composite materials and laminates Glass Materials science On other sites The American Ceramic Society : The Resources section has some useful educational materials.