Found all of the following from different sources on the net. None of this is my writing.
"The use of ceramic as a substitute blade material for steel is picking up, especially in models targeted at the niche and high-end markets. The heat-processed material's zero-pore surface inhibits buildup of germs on the blades. In addition, it does not react with acid or alkali present in food."
"More importantly, ceramic designs retain their sharpness over a long period of time, are rust-resistant and boast a hardness level of 70HRC. Typically, metal ranges only from 52 to 62HRC."
Kyocera Black and White Ceramic Knives
"A ceramic knife is a knife made out of very hard ceramic, often zirconium oxide (ZrO2). These knives are generally produced by compacting Zirconia powder using high pressure presses which apply a pressure of around 300 tons to produce blade shaped blanks. These blanks are very brittle and fragile which can be shattered by a slight blow and special binders are used to retain the shape of the blank until the firing process."
"Like all ceramics these are consolidated into a dense and strong ceramic by solid state sintering at approximately 1400 degrees centigrade for 5–12 hours in a high temperature furnace. The result is a very hard and blunt blade which needs to be sharpened to get the desired cutting edge. The blades are sharpened by grinding the edges with a diamond dust coated grinding wheel."
"When sharpening is needed, ceramic blades cannot be resharpened the same way as steel blades, which are often sharpened with a ceramic whetstone. To sharpen the edge of a blade a material harder than the one that is being sharpened is required, and ceramic knives are usually sharpened with industrial grade diamond sharpeners.
"Ceramic knives will not rust, leading to their use by SCUBA divers. They are also nonconductive and nonmagnetic, which can be useful for bomb disposal operations. Their chemical inertness to both acids and alkalis and their ability to retain a cutting edge far longer than forged metal knives, makes them a very good culinary tool for slicing and cutting through boneless meat, vegetables and fruits. Since they are very rigid they cannot be used for chopping, cutting bones or frozen foods or prying open things, which may cause the cutting edge to chip off or the blade to break free from the handle."
Obviously, one has to take special care of these knives and they don't come cheap.
This 4 piece set runs about $300
I think that in the long run, however, they would pay for themselves in the kitchen.
