Refractron porous ceramics are used for applications that require the wicking and dispersion a finite amount of fluid through the ceramic wicking materials. The precisely controlled porosity and pore size allows components to be custom tailored to the application requirements. In addition to wicks these wicking materials are called applicators, coating rolls, electrodes, atomizers and pads.
The range of Refractron porous ceramics are made by fusing aluminum oxide grains using porcelain bond to form a strong, uniformly porous and homogeneous structure. Refractron's porous ceramic has 40-50% open porosity and is available in pore sizes ranging from 0.25 to 90 microns. Monolithic, single grade, aluminum oxide porous ceramic is available in 6, 15, 30, 50, 60 and 90 micron pore sizes. In addition, Refractron produces a ceramic membrane that uses a medium pore substrate with a thin coating of fine porous ceramic membrane in 0.25, 1, 3 and 6 micron pore sizes.
Aluminum oxide is the standard material and has a maximum operating temperature of 1400 F (800 C). Porous ceramics are resistant to solvents and have good acid resistance with the exception of hydrochloric and phosphoric acids. The advantages of porous ceramics are that they are not only mechanically strong but are also inert and can be cleaned and reused in many process applications. Porous ceramic is used in tough applications to replace porous metal or as an alternative to plastic or fabric media.
Porous ceramic is cleaned and reused using a variety of methods depending on the contaminant to be removed. Specifically tailored techniques include:
- Oven firing
- Dilute acid cleaning
- Solvent cleaning
- Steam and ultrasonic cleaning
The range of porous ceramics includes tubes (from 1/2" to 4" diameter), discs (from 1" to 9" diameter), plates (up to 12" square) and other custom shapes and components made from aluminum oxide where tightly controlled pore size and porosity is critical.
Common uses for porous ceramics for wicking and dispersion include:
- Tube rollers for wicks in printing and photocopying applications, plus critical use ink pads
- Reference electrodes
- Cathodic protection and humidification applications
Other specialty products include a range of adsorbent- filter/drier cores for refrigeration applications, filters, diffusers, vacuum chucks and gas probes.
Porous ceramics are readily machinable using conventional diamond cutters and wheels. Since it is not ductile and the granules are removed the porous ceramic pore structure is not affected by cutting and grinding. Typical diamond tile saws are routinely used to cut porous ceramic tubes and test coupons.