sobota 18. června 2011
What is ceramic knive?
Ceramic knives are not something absolutely new and more and more people all over the world are using them in their kitchens every day. Well, even so many people uses them, really only few people knows what ceramic knives really are, what they are made of and how exactly they works.
So what really is the biggest advantage of ceramic knives? This answer is without any doubt quite simple. The main advantage of ceramic knife is that it is extremely hard. The extreme hardness of such knife means that it is extremely durable. In fact ceramic knifes can last many and many years and it will be still very sharp unlike knives from traditional materials like steel.
Now you maybe ask why are these knives so perfect? Well, it is the material they are made of. The material what these knives are made of is usually zirconium dioxide, this material is also known as zirconia. Zirconai is material, that ranks very very high on Mohs scale of mineral hardness. The number zirconia achieved is amazing 8.5 when steel is about six and diamonds are about 10.
When the material is something so unusual for knife as ceramic, the process of creating such knife is extremely complex. Zirconium powder is first under really very huge pressure pressed to the shape of a blade. Such material is still very frangible so there must be another operations, that will make this material much more strong. This process is called sintring and for more than 12 hours under very high temperatures, which are about 1400°C. After this process has ended you have extremely hard blade, but this blade is still very blunt and needs to be sharpened. Well, this is quite a big problem, because it is not possible to sharpen ceramic knives the same way as traditional knifes are sharpened because of the specifics of the ceramic material. Sharpening of this knife is very hard so it must be done with special grindstone with diamond powder and under water, because there is very important quality cooling.