Soil resistant and self-cleaning surfaces of stainless steel with new sol-gel and ALD coatings

Corrosion, fouling and wearing of metal surfaces are the most common problems that are faced in industry as well as in environmental use. In particular, the maintenance of metal products and also the decrease in their value in use can cause major financial losses for example in construction, transportation, process and food industry. During the last ten years there has been a general interest to study the potential of nanoscale inorganic-organic hybrid sol-gel coatings and ALD coatings to improve the properties of metal surfaces. Sol-gel coatings are usually optically transparent reminding of very thin layers of varnish or lacquer. The main difference is that the sol-gel coatings consist of an inorganic network, which forms the backbone of the coating. By changing the organic and inorganic counterparts and varying their amounts, the properties of the coatings can be modified in a wide scale. TiO2-based or -doped coatings can be photocatalytically active and have self-cleaning properties under UV irradiation. This paper shows how the quality of metal products is improved by applying new thin coatings prepared with ALD or sol-gel techniques. TiO2-modified sol-gel and ALD coatings were used on stainless steel substrates (EN 1.4301, (AISI 304)) with the dry-brushed (2J) surface finish to enhance the soil resistance and cleanliness level of the material.