Ceramic knives are built exactly like traditional steel knives. They, however, have a blade made of a very hard kind of ceramic. The ceramic used in the blades on ceramic knives is often zirconium dioxide. Because of the hardness of these types of blades, they stay sharper longer than steel knives do.
The hardness of the material is determined by the Mohs scale, which ranks the mineral hardness of a substance. The Mohs ranking of the type of blade material used in ceramic knives is 8.5. While diamonds, the hardest substances on the earth, rank at 10, steel blades usually only rank at 6 or 6.5.
Although ceramic knives are very sharp, they are also quite delicate and must be handled with care. If they are used improperly, they can shatter or crack. Simply dropping the knife from too high a distance can chip the ceramic blade. Furthermore, ceramic knives cannot be sharpened in the same way that most knives are. A normal sharpening tool will most likely chip or break a ceramic blade.
If you purchase a ceramic knife, it is important to make sure that you also acquire the special sharpening tool that they require if one does not come with your purchase. Even though ceramic knives are brittle in comparison to steel knives, they are not nearly as delicate as most other ceramic materials. This is because of the special type of ceramic material that is used to make them.
Ceramic knives are used by some chefs, but they have important purposes outside of the kitchen. Because ceramic material does not rust in salt water, they are often used by divers who require such underwater tools. Bomb squads also employ ceramic knives because they do not conduct electricity. Therefore, they make the very dangerous job of disassembling a bomb slightly less hazardous. In cooking, ceramic knives can be an important tool to people with certain allergies.
Some security specialists are wary of ceramic knives. As they can be made entirely without metal, the knives are not noted by metal detectors. There are some machines that can detect ceramic knives. These, however, are not in widespread use. Although the military has developed some ceramic knives that are made without an ounce of metal, most commercial manufacturers have been persuaded to include enough metal in the knives so as to set off metal detectors.