Thin-film deposition

thin-film deposition is regularly happen in petroleum industry, air-conditioning system and many more. for example, we boil water in kettle. and we don't know if there is any particle inside the water. after the water was boiled, put the water into a glass and clear jug and left it for 5 or 6 hours to cooldown the water. after 5 or 6 hours, we look to the bottom of the jug. if the water condition is clean, we cannot see the thin-film deposition. if the boiled water contains corrosion or anyting else, we can see the thin-film deposition. almostly, thin-film deposition happen because an excessive molecul or composite which mix with fluid.