Siddhartha Nanda

  You may have heard about tempered glass before, seen it as an advertised feature in gadget specifications or in the form of screen protectors for mobile devices. But what is tempered glass exactly? What makes it different from standard glass or plastic screen protectors? Most importantly, what will tempered glass offer you as a consumer and it is worth the money? The main difference between standard glass and tempered glass – is in the way they are made. Tempered glass is created by heating and then quickly cooling the material – and thus comes with a different structure. One of the main characteristics of tempered glass is that it breaks differently from standard glass. Whereas normally, glass would break into big uneven pieces, tempered glass shatters into small even pieces. This gets rid of the danger of sharp edges and makes it a much safer option should something happen – for this reason, tempered glass is often referred to as “safety glass”. How a tempered glass is better t...

  The first recorded attempt to use ceramics as replacements for teeth was in about 1774, in Paris, France, by a dentist, Nicholas Dubois de Chémant. Before that time, many other materials had been used to replace teeth, including ivory, bone, wood, animal teeth, and even teeth extracted from human donors. These prior tooth replacements weren’t particularly effective, because they quickly became stained and invariably developed a bad odor. Since 1774, and especially during the past 40 years, dental ceramics have been refined to duplicate the color and translucency of natural teeth and to provide higher strength. Ceramics have been used for tooth replacement and for dentures, and new restoration techniques, such as veneers , inlays , and crowns  have also been developed. A veneer consists of a thin layer of ceramic, usually bonded to the visible surface of front teeth. An inlay is a filling. A ceramic inlay provides a natural-colored alternative to repairing a cavity with a s...

  Once scientists began to understand chemistry, they learned that ruby and sapphire are made from a special combination of aluminum and oxygen atoms that is described scientifically as aluminurn oxide (Al203) and usually referred to by ceramists simply as alumina. Chemists found out that ruby is red because it contains a tiny amount of chromium along with its aluminum oxide. There’s a bit of aluminum oxide in the Earth’s crust (called corundum), but we rarely see it as the gem-quality crystals of ruby or sapphire that we so admire.  Our age-old dream of creating In the nineteenth century, researchers tried to change corundum into gems by heating it to a high temperature. They failed. Others tried chemical synthesis-building the gems from scratch. In 1837, the French scientist Marc Antoine Augustin Gaudin heated a chemical compound called ammonium alum (which turns into aluminum oxide when it’s heated) with a high-temperature torch. He actually did produce some small crystals ...

 Good morning! If your world’s anything like mine, ceramics just woke you from a peaceful sleep. Chances are, your clock or clock radio has an alarm buzzer made from an advanced piezoelectric ceramic. This unusual ceramic vibrates with a loud noise when electricity is applied. If your clock has a quartz mechanism, as most clocks and watches now do, a tiny slice of vibrating piezoelectric quartz ceramic is the timekeeper. However, in this case, the vibrations are so rapid and small that you can’t hear them. Most people have never heard of piezoelectric ceramics, but piezoelectrics are the secret behind a wide variety of products ranging from underwater sonar (submarine searchers) to medical ultrasonic scans to “smart” skis. What are Piezoelectric Ceramics?      Piezoelectric ceramics are known for what are called the piezoelectric and reverse piezoelectric effects. The piezoelectric effect causes a crystal to produce an electrical potential when it is subjected to m...

A crack must zig-zag its way through the stacked platelets in the new ceramic. Thanks to a little inspiration from nature, new ceramics could be made from materials that make them stronger and tougher, researchers have discovered. The new ceramics are inspired by a material called nacre, also known as mother-of-pearl. Nacre is much stronger and tougher than common ceramics and is derived from the nacre of abalone, a small, single-shelled marine mollusk. Biomimicry in bulk:  The Berkeley researchers made large pieces of the tough ceramic, while other scientists mimicking tough natural materials have been able to make only thin films. A tough ceramic’s structure mimics that of abalone shells. This scanning electron microscope image (bottom), taken during a stress test, shows one source of the material’s toughness: damage is widely distributed in small, contained cracks. Ceramics, as the flagship brittle materials, have been the centre of focus on toughness improvements. One of the fi...