Coating thickness refers to the measurement of how thick a layer of material is applied to a surface. This layer can be made of various substances, such as paint, varnish, or metal coatings, and is important for protecting the underlying material from corrosion, wear, and environmental damage. Measuring coating thickness is essential in industries like automotive and aerospace, where durability and performance are critical. Tools like ultrasonic thickness gauges or magnetic thickness gauges are commonly used to ensure that the coating meets specified standards for quality and effectiveness.