Carolyn Aita, a professor at the University of Wisconsin–Milwaukee (UWM) has developed a coating material that can be applied to arrest fractures on almost any material from metal to glass or silicon. The coatings also prevent further degradation and can work in adverse environments, such as in salt spray, oil and high humidity where the tiny crystals in the layers transform to surround and contain the defect. The thin film is grown in layers so that the growth of tiny crystals within a layer is stopped at a particular size and it is the arrangements of the molecules in the tiny crystals embedded in a layer that ultimately determine film characteristics. The substrate is coated in ultra-thin layers by bysputter deposition. For example stainless steel used in artificial bone joints, heart valves to preventing implant rejection or failure or holes in artificial joints, other optical products and biomedical devices can be treated with the coating. Hafnia, zirconia and alumina are used in the smart ceramic coatings for metal.