The international technology group SCHOTT has expanded its range of dielectric materials to include the POWERAMIC® N150 glass-ceramic. POWERAMIC® comprises a family of highly homogeneous and pore-free glass-ceramics for use as dielectrics. These products enable extremely high dielectric breakdown strength compared to other materials.
The energy storage density of POWERAMIC® exceeds that of current capacitor solutions by a factor of up to ten. In high-voltage applications, their excellent dielectric properties allow for significantly smaller, lighter weight passive components, such as capacitors, even at high temperatures.
The advantages of the new POWERAMIC® N150 glass-ceramic include a particularly high constancy of the dielectric properties compared to conventional ceramics, e.g. very low dependence of storage capacity and loss over a significantly broader temperature and frequency range. This opens up potential, especially in pulsed operations with short pulse durations and steep pulse slopes. By that, a variety of new applications in the high-voltage sector, such as transducers in high-voltage networks, but also test, filter and resonant circuit capacitors can be addressed.
“POWERAMIC® N150 glass-ceramic is a highly stable dielectric that builds on the existing material advantages of the POWERAMIC® family and is well-suited for use in applications that involve extremely high frequencies,” explains Tonya Durkin, Product Sales Manager for SCHOTT North America Electronic Packaging. “There are ceramics that have similar material properties on the market. Nevertheless, the more compact designs that new application areas require can only be produced by using glass-ceramics due to their high dielectric breakdown strength.”
The POWERAMIC® material family from SCHOTT is RoHS-compliant and free of lead and halogens.
Capacitors are passive electrical components that store energy in the form of an electrostatic field in the dielectric material between metal contacts. They are commonly used to buffer, stabilize or couple the voltage and power flow in electric power conversion systems. High-voltage capacitors are in ever greater demand; for example, for use in excimer lasers for industrial and medical applications, medical x-ray equipment, high-voltage power supplies (HVPS) for industrial applications, and for renewable energy grids.
However, higher voltages and current densities result in increasing thermal loads. Current capacitor technologies for high-power applications are mostly based on polypropylene (PP) or N4700 ceramics. Both are limited to temperatures below 90° C due to either their loss of capacitance (N4700) or reliability (PP) with rising temperatures. SCHOTT’s latest class of POWERAMIC® materials provides superior performance with respect to energy storage density and dielectric properties for an extended temperature range.
“POWERAMIC® glass-ceramics are highly homogeneous and pore-free, which supports their high dielectric breakdown strength and leads to storage density that exceeds that of current capacitor solutions by a factor of up to ten. This means that smaller and lighter weight capacitors can now be built,” says Durkin. “The nano-sized crystalline structure, which is tightly controlled in a truly amorphous glassy phase, improves the dielectric properties at higher field strength and expands the temperature range compared to ceramic capacitors,” she adds.
SCHOTT is one of the world's leading suppliers of glass-ceramics such as ZERODUR® glass-ceramic with its extremely low thermal expansion for use as mirror substrates in astronomic telescopes, CERAN® glass-ceramic cooktop panels, ROBAX® glass-ceramic viewing windows for fireplaces and stoves and NEXTREMA® glass-ceramic for more demanding industrial applications. By applying the same production method to other chemical compositions, SCHOTT has created a new class of high-performance dielectrics. POWERAMIC® glass-ceramics are titanate-based. As glass-ceramics, they are produced using a two-step process. First, a transparent glass that has a completely amorphous, pore-free structure is melted. In a second step, a well-defined time-temperature profile is applied to grow nano-sized crystals within the glass. Their unique properties are achieved by using highly specified and controlled chemical compositions and processes that allow for narrow tolerances and reliably stable quality.
POWERAMIC® glass-ceramic is supplied as a tested semi-finished product for use in producing capacitors, upon request also in metallized form. It can be used for all commercially available capacitor designs, e.g. doorknob/hockey puck capacitors, SLCs (single layer capacitors), SMD (surface mount device) capacitors, as well as in custom designs to meet individual customer specifications.
POWERAMIC®, ZERODUR®, CERAN®, ROBAX® and NEXTREMA® are registered trademarks of SCHOTT AG.
SCHOTT (schott.com) is a leading international technology group in the areas of specialty glass and glass-ceramics. The company has more than 130 years of outstanding development, materials, and technology expertise and offers a broad portfolio of high-quality products and intelligent solutions. SCHOTT is an innovative enabler for many industries, including the home appliance, pharmaceutical, electronics, optics, automotive, and aviation industries. SCHOTT strives to play an important part of everyone’s life and is committed to innovation and sustainable success. The group maintains a global presence with production sites and sales offices in 35 countries. With its workforce of approximately 15,400 employees, sales of $2.55 billion were generated in fiscal year 2013/2014.