Whether mechanical parts or metal components, the most prominent problem is surface wear or corrosion or both. Here is a brief introduction of the coating application guide: 1. Wear-resistant - the largest application field of thermal spraying technology at high and low temperatures. This kind of coating is divided into the following types: (1) Resistance to adhesive wear or scratch - when two surfaces slide relative and debris sticks from one surface to the other, adhesive wear or scratch occurs. Special typical coatings are cobalt-based tungsten carbide and nickel chromium/chromium carbide coatings. (2) Abrasive wear - abrasive wear occurs when a harder surface slides on a softer surface and there is wear between the two surfaces. When the fiber and silk thread pass through the surface at high speed, abrasive wear also occurs. Proprietary typical coatings are cobalt-based nickel-chromium alloy, self-fluxing alloy mixed molybdenum and chromium oxide coatings. (3) Resistance to micro-vibration wear - cyclic stress caused by repeated loading and unloading leads to surface cracking and large area shedding. The special typical coating is aluminum oxide/titanium dioxide coating. (4) Resistance to cavitation wear - liquid flow produces mechanical impact on the surface. The special typical coating is aluminum bronze coating. (5) Erosion wear resistance - Erosion wear occurs when particles carried by gas or liquid impact the surface at high speed. Special typical coatings are aluminum oxide/titanium dioxide and aluminum oxide coatings. 2. High temperature resistance and oxidation resistance - this kind of coating is resistant to chemical or physical decomposition and improves the high temperature performance of parts. This type of coating is divided into the following types: (1) Thermal barrier coating - acts as a thermal barrier between the part and the high temperature environment. Typical coating is zirconia coating stabilized with yttrium oxide. (2) High temperature oxidation resistant coating - protects the substrate against high temperature oxidation. Typical coating is nickel/chromium coating. (3) Anti-corrosion coating - protects the substrate exposed to hot corrosive gases. Typical coating is nickel/chromium coating. 3. Anti-corrosion coating - The selection of this kind of coating is relatively complex, because the parts are in service, the ambient temperature and various media have certain requirements on the coating materials. Generally, cobalt-based alloys, nickel-based alloys and oxide ceramics are used as coating materials to block the penetration of corrosive media by improving the tightness of the coating; Reasonably select the oxidation/reduction potential of the coating material and the part base material to prevent electrochemical corrosion, and apply the sealing agent to inhibit corrosion. 4. Conductive coating or insulating coating - this kind of coating can be divided into the following types: (1) Conductive coating - The special typical coating is copper coating. (2) Insulating coating - The special typical coating is aluminum oxide coating. (3) Shielding coating - The typical coating for electromagnetic interference (EMI) or high frequency interference (RFI) is copper coating. 5. Restored size coating - This kind of coating is mainly used to repair parts that are worn or processed out of tolerance. The selection of coating materials mainly depends on the use requirements of parts.