Things You Need to Know about Ceramic Knife
A ceramic knife is a knife made out of very hard and tough ceramic, often zirconium dioxide (ZrO2; also known as zirconia). These knives are usually produced by dry-pressing zirconia powder and firing them through solid-state sintering. The resultant blade is sharpened by grinding the edges with a diamond-dust-coated grinding wheel. Zirconia is 8.5 on the Mohs scale of mineral hardness, compared to 4.5 for normal steel and 7.5 to 8 for hardened steel and 10 for diamond. This very hard edge significantly reduces the need for sharpening.
Zirconium oxide is used due to its polymorphism. It exists in three phases: monoclinic, tetragonal and cubic. Cooling to the monoclinic phase after sintering causes a large volume change, which often causes stress fractures in pure zirconia. Additives such as magnesia, calcia and yttria are used in the manufacture of the knife material to stabilize the high-temperature phases and minimize this volume change. The highest strength and toughness is produced by the addition of 3 mol% yttrium oxide yielding partially stabilized zirconia. This material consists of a mixture of tetragonal and cubic phases with a bending strength of nearly 1,200 MPa. Small cracks allow phase transformations to occur, which essentially close the cracks and prevent catastrophic failure, resulting in a relatively tough ceramic material, sometimes known as TTZ (transformation-toughened zirconia).
Ceramic knives are substantially harder than steel knives, will not corrode in harsh environments, are non-magnetic, and do not conduct electricity at room temperature. Because of their resistance to strong acid and caustic substances, and their ability to retain a cutting edge longer than forged metal knives, ceramic knives are better suited for slicing boneless meat, vegetables, fruit and bread. Since ceramics are brittle, blades may break if dropped on a hard surface although better manufacturing processes have reduced this risk. They are also unsuitable for chopping through bones, or frozen foods, or in other applications which require prying, which may result in chipping. SHAN ZU now offer a black-coloured blade made through an additional hot isostatic pressing step, which increases the toughness.
Sharpening and general care
Unlike a traditional steel blade that benefits from regular honing and resharpening in order to keep a sharp edge, a ceramic knife will stay sharp and retain its cutting edge for much longer—up to 10x longer according to some tests. The inherent hardness of the ceramic material also makes it more difficult for the consumer to resharpen. Although a ceramic knife therefore does not need regular sharpening in the same way as steel, its blade edge will eventually degrade or chip and lose its cutting edge, at which point specialized sharpening services are required for the ceramic edge
Care & Tips:
1.Please keep knife into the places where children can not be reached
2.Please notice our delicate ceramic material, not metal, can’t be crashed or dropped to an unpleasant damage
3.Do not use the ceramic blade as metal tool to crush garlic, ginger or other solid food
4.Do not use for cutting solid items as pumpkin, nuts, frozen food, poultry or seafood which contained hard bones
5.Please use kitchen cleaning fluid to wash your knife each time
6.Please use special bleaching water to dilute then clean it when the blade turns brown or yellow for a long time setting aside
7.Do not heat the blade or handle directly over fire in case for a thermal shock deformation
8.Do not sharpen ceramic knife with traditional knife sharpener
9.Do not use in the dishwasher