On stainless steel, aluminum or matt titanium surfaces, fingerprints are visible because those metals have a very reactive surface (high free surface energy), and a great wett-ability which causes a color change in contact with the hydrolipidic film (the wetting substances).
Metal surfaces like titanium or stainless steel are generally difficult to clean and, fingerprints and stains can hardly be removed. This is due to the strong chemical bond that the highly reactive metal surface can produce.
By designing a specific coating based on sol-gel technology, it is possible to control fingerprint stains, to make them less visible and remove them more easily. The optical parameters (reflective index) and specific coating material surface energy are therefore modified to achieve a good anti-fingerprint performance.
The NANOXID sol-gel coating developed by IONICS is a unique product which meets all the requirements regarding (small) thickness of the layer, aesthetics, haptics and/or chemical and mechanical performance.
The product developed and adapted to the specific requirements of major domestic appliances manufacturers is a hybrid, organic/inorganic sol-gel that forms transparent layers ranging from <1 µm to 3 µm. It is possible to tailor the material for different grades of gloss or mattness. Since the chemical composition of the sol-gel is similar to that of glass, the cold metal feel of the substrate is kept while chemical and mechanical resistance is improved.
A major advantage of the selected material is that it can be stored and manipulated at room temperature and has a shelf life of several months. Most sol-gels have to be cooled and used immediately after production.