| Introduction | | | | could withstand the high-frequency electromagnetic |
| Have you ever wondered about the myriad materials | | | | fields. As a result, electro-ceramics such as steatite |
| from which stuff is made that we come across in | | | | were developed. Subsequently, other |
| our daily life? The numerous materials which have | | | | electro-ceramics such as magnetic ceramics (ferrites) |
| unique characteristics and which are used for making | | | | were developed, followed by capacitor ceramics |
| various articles used in everyday life- these materials | | | | (titanates) and electro-mechanical ceramics |
| attract the attention of the young inquisitive minds in | | | | (piezoelectric ceramics). In the later part of the 20th |
| engineering classrooms all over the world. | | | | century, the need for protecting tiny transistors and |
| Today, let me introduce you to the world of | | | | ICs from ambient conditions led to the development |
| "CERAMICS". | | | | of ceramic packaging materials which facilitated |
| "Ceramics" are the materials which are often | | | | further miniaturization. |
| misunderstood as materials used merely for pottery | | | | Concurrent with the development of |
| and decorative objects. Even though the word | | | | electro-ceramics, another sub-class of advanced |
| ceramic is derived from the Greek word "Keramos", | | | | ceramics which came to be called structural ceramics |
| meaning potter's clay or pottery, what many people | | | | progressed, which had high structural and chemical |
| don't realize is that ceramics play an important role | | | | integrity characterized by properties such as |
| almost everywhere you see and many times in | | | | extremely high hardness, stiffness, and heat and |
| places that you can't. | | | | chemical resistance. These structural ceramics found |
| Besides the everyday objects of glassware and floor | | | | applications in various industries, for example in the |
| tiles, the ceramics of today are critical in helping | | | | space industry as heat and wear resistant tiles and |
| computers and other electronic devices operate, in | | | | nose cones on space shuttles, in the aerospace |
| medical devices for improving people's health in | | | | industry as bearings and turbine rotors, in the |
| various ways, in providing global telecommunications, | | | | chemical industry as chemical resistant seals and |
| and in protecting soldiers and vehicles during combat. | | | | conduits, in the defence industry as bullet-proof vests |
| Ceramics are generally defined as inorganic, | | | | and armor plates for vehicles, in the biomedical |
| non-metallic materials that are made from powdered | | | | industry as hip-joints, knee-joints and orbital implants, |
| chemicals. They are typically crystalline in nature (their | | | | and so on. |
| atoms are arranged in a systematic manner) and are | | | | Further Developments |
| compounds formed between metallic and non-metallic | | | | As ceramic technology has rapidly progressed over |
| elements such as aluminum and oxygen (alumina, | | | | time, the definition of advanced ceramics has |
| Al2O3), calcium and oxygen (calcia, CaO), silicon and | | | | expanded to include a much wider range of |
| nitrogen (silicon nitride, Si3N4), and so on. | | | | compositions used in a large variety of applications. In |
| Various "advanced ceramic" products are | | | | broader terms advanced ceramics also include glass |
| manufactured by combining high-purity chemicals into | | | | (which has a non-crystalline or amorphous random |
| desired shapes and then heating them to very high | | | | atomic structure), enamel (a type of glassy coating), |
| temperatures. The shaped ceramic products thus | | | | glass-ceramics (a glass which is partly crystallized), |
| made can have many desirable properties such as | | | | and inorganic cement-type materials (cement, |
| heat resistance, hardness, strength, low electrical | | | | concrete, plaster and lime). |
| conductivity, and unique electro-mechanical | | | | Advanced ceramics include yet another sub-class of |
| characteristics. Thus advanced ceramics are ceramics | | | | ceramics called refractories. Refractories are critical |
| which are made by tightly controlled methods and | | | | materials which reduce heat losses from industrial |
| therefore they exemplify an "advancement" over the | | | | ovens, also called kilns, and at the same time they |
| general definition. As a consequence of these refined | | | | resist very aggressive conditions including chemical |
| methods, a new class of ceramics called "advanced | | | | and acid attack, very high temperatures (up to |
| ceramics" is born. | | | | 3200°F), abrasion, mechanical impact, and more. |
| Long lasting and harder than steel, advanced ceramics | | | | These refractory ceramics enable manufacturers of |
| may be found in aircraft engines, automotive engines, | | | | commodities such as metals, alloys, cement, glass, |
| cutting tools used for making metal products, the | | | | etc to operate efficiently and profitably. Thus they |
| skin of space shuttles, knives, bullet proof armor, | | | | play a very important role in growing the global |
| artificial hip-joints, computers and microelectronics. | | | | economy. |
| History | | | | Advanced ceramics continue to be developed even |
| One of the first uses of advanced ceramics was for | | | | further; new ceramics and their combinations are |
| corrosion-resistant stoneware vessels in the chemical | | | | constantly being improved and newer products are |
| industry as early as the 1750s.Then came porcelain, | | | | continually being introduced in various industries. |
| which was first used in dentistry in the 1850s. With | | | | The progress in advanced ceramics is so rapid that |
| the invention of electric light in the 19th century, | | | | the advanced ceramics of today are strikingly |
| ceramic materials based on porcelain for electrical | | | | different from those made even a few years ago. |
| insulation were developed. | | | | Ceramic engineers eagerly anticipate further rapid |
| This was followed by the blooming of the radio and | | | | developments of newer ceramic materials and their |
| television broadcasting industry in the 20th century, | | | | combinations that will find even more exciting |
| which needed special heat resistant materials that | | | | applications in the future. |