How are ceramic knives made? It’s no easy task, but with today’s technology, it seems easy. The process is a mixture of old school techniques combined with a bit of modern technology.
The raw materials (mostly water and ceramic powder), are mixed in a drum, not the musical instrument but something similar to a sealed cement mixer. This part of the process creates uniform particles. The more uniform in size, the harder the material can be pressed. The liquid mixture is then sprayed onto a flat surface and then dried. Once all the liquid is gone, only a fine powder remains. This is the base for the ceramic knife blade.
The fine powder is then poured into a knife shape mold. The mold is then pressed to over 10,000 psi. The pressure turns the powder into a solid piece which will eventually become the ceramic blade.
The blade is then removed from the mold and fired in a kiln at around 1400 degrees celsius. This is a similar process to used to fire traditional ceramics except a more controlled temperature setting is used here. During this process the knife will shrink about 1/4 its original size. The material becomes very dense and super hard.
The edge is then sharpened using a diamond coated sharpening wheel, a handle is attached to the end and you have yourself a ceramic knife.
The differences you will find in the hardness of a ceramic knife is usually due to changes in 2 variables, the amount of pressure that is used and the amount of heat. More pressure and a more precise temperature will result in a higher quality material.
How sharp the knife is boils down to how much time and effort is put in during the sharpening precess. If the ceramic material is of high quality, the manufacturer can sharpen the edge a lot finer without the risk of chipping. If the material is not hard enough, the manufacturer will usually refrain from sharpening it too much due to the risk of lowering its durability.
Although most ceramic knives look the same, they are not all created the same. There are many high quality ceramic knives on the market, but there are also a lot of low quality ceramic knives too.