Siddhartha Nanda

  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...

  CERAMICS IN SPACE The inherent brittleness of ceramics is the main reason why they are unsuitable as structural material for most applications. However, ceramics do stand out in many highly specific aspects, especially when it comes to high temperatures and chemical stability. In this article, we explore the crucial roles of ceramics in spacecraft and how they save the day where metals falter. Thermal protection system in spacecrafts: One of the more common use cases for ceramics in spacecraft is as part of the thermal protection system. To understand why a ceramic material is the ideal candidate for this application, it is important to look closely at the different heat dissipation mechanisms.             When a spacecraft enters any kind of atmosphere at orbital speeds, it experiences significant surface heating through atmospheric drag. This holds even true for the relatively thin Martian atmosphere, which has only 1% of...