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Surface modification is the act of modifying the surface of a material by bringing physical, chemical or biological characteristics different from the ones originally found on the surface of a material. [1] This modification is usually made to solid materials, but it is possible to find examples of the modification to the surface of specific ...
A coating is a covering that is applied to the surface of an object, or substrate. [1] The purpose of applying the coating may be decorative, functional, or both. [ 2 ] Coatings may be applied as liquids , gases or solids e.g. powder coatings .
The desired coating material is typically dissolved or suspended into a precursor solution or slurry (sometimes referred to as "ink") and delivered onto the surface of the substrate through a precise coating head known as a slot-die. The slot-die has a high aspect ratio outlet controlling the final delivery of the coating liquid onto the substrate.
In general, the lower the surface tension of a liquid coating, the easier it will be to form a satisfactory wet film from it. The difference between the surface tension of a coating and the surface energy of a solid substrate to which a coating is applied affects how the liquid coating flows out over the substrate.
Thermal spraying techniques are coating processes in which melted (or heated) materials are sprayed onto a surface. The "feedstock" (coating precursor) is heated by electrical (plasma or arc) or chemical means (combustion flame).
Some of the surface modification techniques listed above are particularly used for certain functions or kinds of materials. One of the advantages of plasma immersion ion implantation is its ability to treat most materials. Ion implantation is an effective surface treatment technique that be used to enhance the surface properties of biomaterials.
Polymeric coatings are another area of applied grafting techniques. In the formulation of water-borne paint, latex particles are often surface modified to control particle dispersion and thus coating characteristics such as viscosity , film formation, and environmental stability ( UV exposure and temperature variations).
Detonation spraying produces coatings of very high chemical bond strength and hardness. Coatings are of low porosity, oxygen content and have a low to medium surface roughness. This is achieved due to the extremely high temperatures and velocities produced by the detonation gun during surface coating application. [6]