Ceramic capacitors are used in a variety of electronics, ranging from computers and mobile phones to telecommunications transmitter stations and high voltage laser power supplies. One of the most widely used ceramics in capacitors is lead zirconate titanate, but it is hazardous to health and the environment once it’s disposed of. Scientists are trying to find other less hazardous ceramic materials for use in capacitors.
Perovskite oxynitrides are said to be particularly promising, being cheap and easily fabricated with a distinctive crystalline structure. However, ceramics manufactured from these materials need to be made denser to improve their insulating properties. This is usually done through sintering; however this process can lead to a change in the chemical composition of the material, turning it from an insulator to a conductor.
The researchers sintered the perovskite powder SrTaO2N at a temperature of 1450°C for three hours. They then annealed the material by heating it with flowing ammonia at 950°C for 12 hours and then allowed it to cool.
They found that the surface of the material, but not its interior, after this process displayed a dielectric property called ferroelectricity. The scientists claim that this is the first time a ferroelectric response has been observed on oxynitride perovskite ceramics, making it a suitable dielectric material for multi-layered ceramic capacitors.
KEMET to reveal advanced ceramic capacitor technology at APEC 2016 KEMET is to preview its multilayer ceramic capacitors (MLCCs) featuring its U2J Class-1 dielectric technology at the 2016 IEEE Applied Power Electronics Conference and Exposition (APEC). KEMET’s F862 polypropylene film capacitors are claimed to deliver superior performance in high-humidity or series-coupling applications. It is said that, when used as X2 capacitors in equipment deployed in harsh environments, such as smart meters, the devices can achieve life ratings over 15 years. |
