Ceramic knives are special knives made from very tough and hard ceramic, often known as the zirconium dioxide (ZrO2). These knives are normally produced and manufactured, through the dry pressing of the zirconia powder and afterwards, they are fired through a solid-state of heating without melting. The resulting blade will be sharpened by grinding its edges using a diamond-grinding wheel. The hard material in a ceramic knife is next hardest to diamond.
This material is composed of a combination of cubic and tetragonal phases having a bending strength of 1,200 MPa. Phase transformation is allowed to occur by small cracks. The essential close of the cracks will avoid catastrophic failure, which will result to a significantly tough and hard ceramic material.
Zirconium oxide is often used because of its polymorphism that undergoes three phases: first is the monoclinic, second is the tetragonal, and third is cubic. When cooling happens to its monoclinic phase, right after sintering may cause big volume of change, which can lead to stress fractures in the pure zirconia.
Properties of Ceramic Knives
Ceramic knives are lighter in weight compared to steel knives. They do not corrode in punitive environments. They are also non-magnetic which means they are not good conductors of electricity at a room temperature.
Ceramic knives have strong resistance to caustic substances and strong acids. They have the ability to retain their cutting edge even longer than metal knives which are forged. These type of knives are suited and better for slicing vegetables, boneless meat, bread and fruit.
Ceramic are known to have brittleness but its manufacturing is now more improved, reducing the risk of blades to be broken when dropped on hard surfaces.
Despite the durability of ceramic knives, they also have limitations due to its sharpness and thinness. It is not suitable for chopping of frozen foods or through bones. Forcing to use them on such instances, may cause catastrophic failure.
General Care and Sharpening
Unlike that of metal or steel blade knives, that requires regular re-sharpening and honing to keep the edges sharp, ceramic knives can stay sharp for a longer period, retaining its cutting edge. Some tests show that the cutting edge of ceramic knives can last 10x longer that ordinary knives.
Although this knife doesn’t need too much re-sharpening, its cutting edge may degrade naturally due to environmental factors like storage or if it is not properly protected.
This ceramic material has inherent hardness, which makes re-sharpening difficult. Traditional sharpening or honing may not be effective. However, suppliers are taking various approaches on the how to re-sharpen. Some suggested that ceramic knives can be one of those considerable disposable items but some manufacturers today have included sharpening devices for this kind of knife.
There are additives used in manufacturing of a ceramic knife material such as calcia, magnesia, and yttria. They are used for the purpose of stabilizing the phases of high-temperature and in minimizing the volume of change. Highest toughness and strength produced in the addition of yttria oxide in 3 mol% can partially yield a stabilized zirconia.
By: John Rowe A chef at heart but an avid tinkerer. I have worked in restaurants for the last 17 years and want to give back to my community of foodies like me. I started this site to give more people more accurate info on Advanced Ceramic knives and be the single source for unbiased info on the subject. I only allow researched an academic articles backed by science and facts.
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