n oxide film beneath the passivation film. Sometimes, the tin oxide film and the passivation film are collectively known as the oxidation film. See the following figure for the composition of an ETP.Generally, it is believed that the tin free steel (TFS) is composed of four layers, including steel base, metllic chromium layer, chromium oxide layer and oil film, as shown below.3. Product Feature and ApplicationColor-printed metl, which is bright-colored, shiny and rust-resistance, can be used in