The basic principle of PVD coating is to evaporate or sputter a solid target material using physical means in a vacuum environment, and then deposit the evaporated atoms or ions onto the substrate surface to form a thin film. By heating or bombarding, the source material (usually a metal or alloy) is converted into gaseous atoms or molecules. This can be achieved through various methods, such as resistance heating, electron beam heating, or plasma bombardment, where evaporated or sputtered atoms or molecules move in vapor phase within a vacuum chamber. The vacuum environment reduces the collision of gas molecules, allowing atoms or molecules to move freely and reach the surface of the substrate. PVD coating technology has the characteristics of pollution-free, energy-saving, and high efficiency, and is widely used in fields such as automotive, aerospace, electronics, and optics. By selecting different target materials such as metals, alloys, ceramics, etc., coatings with different performance characteristics can be obtained to meet various application requirements