Few people today, except experts, understand exactly what is hidden under the name “ceramic coating”: what it is, whether it really consists only of natural materials, as they say in the ads.
Let’s turn to the process itself. Ceramic products are made by sintering clay and their mixtures with mineral additives, as well as oxides and other inorganic compounds. The sintering temperature is about 1000°C.
It is impossible to put a natural ceramic coating on aluminum cookware. Aluminum begins to melt at about 600 ° C. Therefore, the coating is applied using a special technology called “sol-gel technology,” which reduces the sintering temperature.
This technology involves taking an ash and turning it into a gel. In the case of “ceramic” coatings, these sols are made from organosilicon compounds. Different coating manufacturers use different “bricks” for coating. The starting substance is obtained through a chemical process – the combination of silicon with chlorine. Thus, the number of chemical transformations, which goes through the source material, is so great that suggests one answer – we can not speak about any natural “ceramic” coatings.
Manufacturers claim that the composition of coatings made of ceramics contains only natural materials. Of course, there is silicon and oxygen. But it is impossible to form a “ceramic” coating without adding catalysts and hardeners to the base. There can be several of these components in one coating layer, and the number of layers can be different.
Catalysts are chemically extremely active organic components, but without them the process of formation of a ceramic coating will be very slow. Without hardeners, this process is not possible at all. Because of the low sintering temperatures (180-250 °C) of the “ceramic” coating, the organic components of the original materials may remain in the coating. Since the sintering temperatures coincide with the operating temperatures of the cookware, the organic components not removed from the coating can be released into the food and the environment.
Many consumers of cookware with ceramic coating complain about the rapid loss of non-stick properties, while the coating may not change in appearance. This is because the organic substituents of the coating collect on the surface in the form of “little umbrellas” covering the inner silicon-oxygen structure. It is these organic substituents that give “ceramic” coatings their non-stick properties. However, they easily volatilize when heated, which means that the lifetime of the “ceramic” coating as non-stick is very short. In addition, these organic substitutes have a chemical base, which reduces the safety of cookware.
It turns out that ceramics can be dangerous to health, even if made from natural materials without harmful impurities. The reason is the radioactivity of raw materials. Clays may contain naturally occurring radionuclides, which, when decomposed into isotopes, irradiate humans. During burning, their concentration increases significantly, sometimes several times.
Ceramic cups and plates pose a particular danger in this regard, because the radionuclides they contain get inside the human body together with the food. The result is that the body is exposed to internal beta radiation that is far more dangerous than external sources of radiation. The relevant studies have found that a daily hour and a half of contact with “contaminated” dishes for a year turns out to have a total radiation dose a hundred times higher than the norm of 0.1 mSv/year established for the population.