Blast glass

a group of researchers from the Central Glass and Ceramic Research Institute, Kolkata, has developed a process to obtain glass ceramic material from the blast furnace slag generated in iron and steel plants. The innovation holds good potential for the cookware industry as the new class of materials has an ultra-low thermal expansion coefficient and uses low cost raw materials.

Safe fibres

fine ceramic fibres have been in use in a variety of forms since a long time. Finer fabrics are strong, flexible and, unlike coarser fibres, they do not irritate the skin. But in recent times, the question of ceramic fibre use has returned to haunt us as a major health issue. Ceramic fibres finer than 1 micron in diameter are known to be carcinogenic and fibres finer than 3 microns can be inhaled.

Ceramic wonder

Japanese workers have developed the first neodymium-doped yttrium-aluminium-garnet (Nd:YAG) laser, based on ceramics. Nd:YAG lasers are used for micro fabrication and in medical work. Normally, lasers are made from monocrystalline material. The size and power of these is limited by the size of single crystals that can be grown. However, growing large crystals can take over a month and defects often crop in during growth.

Clean ceramics

the smooth, white surface of your bathroom sink hides the fact that the process of making it is a notoriously dirty and polluting one. Aluminium oxide ceramics which find applications in a range of products (from sinks to lasers) are made by dissolving aluminium oxide powder in organic solvents and using many other chemicals in the process.

Shrinking ceramic

GENERALLY, the laws of physics are very rigid, but this one is found to be rather flexible. It is a well established theory that a material expands on heating. The reason for this thermal expansion is the violent increase registered in the vibrations of atoms or molecules of the material due to extra energy. The more the heat supplied, the more the atoms vibrate and take up more space. Or so it is with most materials.

Bending ceramic

Malleable and bendable ceramic materials have been developed in Saarbrucken, Germany. Deutchland (No I 9/10). Scientists at the Saarbrucken's Institute for New Industrial Material have recently developed what they refer to as 'nano powder'. It consists of almost unimaginably small ceramic particles, billions of which would fit on the head of a pin. The ceramic particles are surrounded by an extremely thin lubricating fIlm which ensures that the individual particles do not stick to one another and are able to move freely. This produces rather

Shaping better

German researchers from the Fraunhofer Institute For Ceramic Technologies, have developed a 'hot moulding' technique for moulding thermoplastics. According to the scientists, this technology is simpler and cheaper than injection mould- ing. The technique involves mixing ceramic powder with waxes and paraffins that melt at low temperatures. The concoction is then warmed slightly and pressed into the mould at low pressure. After the mixture hardens, the binding agent is removed by evaporation and later fired at high temperatures.

Material in, metal out

Researchers from Calcutta have managed to develop a new ceramic that boasts of properties which could ultimately mean the replacement of conventional metallic parts used in refractories and engines. The material which is called 'sialon' ceramic', has been developed by a team of scientists led by Siddartha Bandopadhyay from the Calcutta-based Central Glass and Ceramics Research Institute using - such as clay - as the starting material and a novel sintering technique. The researchers claim that the sialon ceramic has superior mechanical, chemical

Return to glaze

Traditional Indian potters fig" 14 extinction today due to their ig rance of improved technology ceramics and poor financial cod tion. However, now any good op, lity clay available to potters all co the country at throw-away o could be used to produce glazed 0 tery that bears a huge market val Changing Villages (Vol 14, lamnO March, 1995) reports that in L with this objective, at the insistel of Rural Technology Instin Gandhinagar, Gujarat, a sponW project was taken up to develop appropriate technology for the duction of glazed pottery fn Balasinor common