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.
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
The benefit of the sandwiching structure is to strike a balance both the harder & sharper edge and better durability of the entire blade
The most simple multi-layer blades have a three layer structure, made of a hard steel core that is sandwiched by soft (resilient) steel so that the hard core is exposed only at the cutting edge. That realizes better durability or chip-resistance.
* Hard steel core is generally easier to be chipped, that’s why the sandwich structure can be a good solution.
One of the applied approach of the multi-layer blades eventually leads to a Damascus pattern. Therefore, such a multi-layer structure can not simply be said ‘no meaning’ from a view of strength and durability. Many sandwich outer layers covering the center core realize the unique damascus pattern for each knife. You can get only one design of the blade in the world. Therefore damascus knives are much recommended as a gift as well as just for better cooking or hunting experience. One demerit of the damascus knives is the cost because of additional production process. It takes the best and worst qualities of different kinds of steel and uses them to create a stronger, more durable knife. All of this series are made as described above, hence the higher pricing. It takes countless hours of labor to produce one single blade, but a lifetime guarantee can ensure that your money is well spent. If you have yet to own a well made, hand crafted super knife we urge you to order today. We will make sure you are satisfied in every way possible
Selecting the proper coarseness for your bench stone is an important first step in sharpening your knife. Not every knife needs to start at the coarsest stone you have, on the other hand a very dull knife can not be sharpened on only your finest stone. Starting with the proper coarseness will ensure that you achieve the edge you need quickly. If your knife is very dull or has a nicked blade, start with your coarsest stone. The coarse stone removes material quickly so a poor edge can be refined quickly. However, the coarse stone must be followed up with your finer stone to refine the edge. If your knife is only slightly dull and just needs a quick touch up, starting at a medium or fine stone can save you time. Starting on a fine stone requires fewer steps but must only be used on an edge requiring little work.
Selecting the right sharpening angle is the next step in sharpening. For more detailed instructions on selecting the right angle. Regardless of the method of sharpening, a bevel angle should be selected. This angle doesn't need to be exact but following some general guidelines is a good idea. Most knife manufacturers recommend a roughly 20 degree angle. Depending on the use of your knife, you can move up or down from that angle. A fillet knife is never used on anything hard so an angle a few degrees less will produce a sharper edge. On the other hand, a survival knife with various uses can benefit from a more durable edge a few degrees larger.
Some stones need water, while other stones need oil for floating the swarf (small metal filings created when sharpening) away. Simply apply a few drops of either oil or water directly to the stone. (We recommend using an inexpensive spray bottle for applying the water.) The lubricant you need is determined by the type of stone you are using. Water stones and diamond stones require water. Oil stones such as India, Crystolon and Arkansas stones use oil for a lubricant.
Starting with the coarsest stone needed for your knife, you will progress through each finer stone until you have reached the desired level of sharpness.
Rest your knife on the stone at your chosen bevel angle. An easy method for determining the angle by eye is to visualize a 45 degree angle and then take half that amount. That will give you a ballpark estimate of the angle and then you can adjust accordingly up or down. With a slicing action bring the length of the knife across the stone with a motion that starts with the heel of the knife on the stone and ends with the point of the knife. The motion should resemble a sweeping arc pattern across your stone. Be very careful to maintain the angle of the knife on the stone. Longer curved knives provide additional challenges but as long as you can maintain the angle you will be sharpening very effectively. Repeat this process on the other side of the knife and continue repeating until you have sharpened your knife though all your stone grits.