Nuttha Thongyai. Study of stainless steel surface cleanability . Master's Degree(Industrial Chemistry (Material Science)). King Mongkut's Institute of Technology North Bangkok. Central Library. : King Mongkut's Institute of Technology North Bangkok, 2005.
Abstract:
Stainless steel is a common and widely used material with high mechanical
strength and relatively high resistance to chemical corrosion. In addition, it is widely
used for outdoor building structure. In usual environment, cleaning surface of
building material mostly will be taken by the rain fall or water rinsing but in practical,
stainless steel surface cleaning of building material for example: facades, panes and
walls generated many troubles i.e. consumption of energy and chemical detergents
resulted in high expenditure. In this work, stainless steel, AISI 304 RB, surfaces were
treated in various ways, such as chemically cleaned, Ar-plasma treated, coated by
TiO2, coated by SiO2, SiO2+TiO2 (composite) and TiO2/SiO2 (bi-layers), in order to
obtain more hydrophilic surface. If surface has high ability to adhere to water than
contamination it means that this type of surface will enhance wettability and
cleanability. Contact angle measurement was selected to identify cleanability of the
surface because its a simplified method for characterizing the interfacial tension
presented between surface, liquid and vapor phase. A common illustration of surface
cleanability is the behavior of water droplets on clean surface exhibiting flat shape.
The methods for contact angle measurement were done in two ways i.e., one-liquid
and two-liquid methods. The surface energies were calculated from contact angles
data of various surface treatments. Results from one-liquid method showed that
surface treatment affect to surface energy. Newly prepared surface had nearly the
same surface energies but after ageing 2 weeks surface energies for all specimens
were reduced by adsorbed contamination. In contrast, surface coated by composite
can maintained surface energy as the beginning due to acidity and water trapping
effect. While two-liquid method was not successful to determine surface energy of
coated surfaces.