Coatings with functional effects are often highly regulated by standards such as BA, ASTM, DIN, ISO, QUALICOAT, QUALINOD, etc. As mentioned in the paragraph above [Functional Coatings], there is a need for regulation of coatings that perform specific functions. In the case of TiN coatings in engines, the coatings are applied to tight tolerances. Above specified limits, the coating can impede the function of engine components, while below these limits, components can fail without adequate protection from the frictional stresses applied to them. When components are manufactured, coatings are inspected to ensure they are within these parameters; alternatively, coatings can be measured at various intervals over the life of the component to ensure they have not been worn. Abrasion of the coating can lead to corrosion of the substrate, which can lead to catastrophic failure, especially if the component is used in the automotive, aerospace, rail or marine industries.
A second reason to measure coatings strictly from a financial perspective. For example, current prices for gold, platinum and silver mean that companies that manufacture components with these coatings could lose money if they added too much coating to their components. An example is silver plating on copper wire used in wiring in aerospace. To ensure that the wire meets the strict standards of the field, more silver is often applied to the copper wire to ensure the wire is within specification. For the manufacturer, this translates to a cumulative cost of $250,000 per year just to over-deposit the silver coating. Another example is the painting and painting of car bodies by the automotive industry. By saving 1µm of overpaint/clearcoat, manufacturers can save £1 per car. Around 2.3 million cars were registered in the UK in 2019, suggesting an annual saving of £2.3 million (Institution of Motor Manufacturers and Traders, 2020). Therefore, the necessity of measuring coatings becomes clear.
