Principle Of Ion Plating
Ion plating refers to using gas discharge to ionize gases or vaporized materials under vacuum conditions. Evaporation materials or their reactants deposit on the workpiece under the action of ion bombardment of gas ions or vaporized materials. Ion plating can divided into magnetron sputtering ion plating, reactive ion plating, hollow cathode discharge ion plating (hollow cathode evaporation), multi-arc ion plating (cathode arc ion plating) and so on. Ion plating combines glow discharge, plasma technology and vacuum evaporation technology, which not only significantly improves the performance of the coating, but also greatly expands the application of the coating technology. In addition to the advantages vacuum sputtering, it also has the advantages of strong film adhesion, good diffraction, a wide range of materials that can be plated and so on. The basic principle of ion plating is to ionize the vapor of a metal or alloy by means of a glow or arc discharge of an inert gas. Ion plating includes the heating, evaporation, and deposition processes of the coating materials (such as TiN and TiC). Evaporated coating material atoms undergo a small amount of ionization when passing through the glow region, and fly to the workpiece under the action of an electric field, it strike the surface of the workpiece with energy of several thousand electron volts, and can be injected into the substrate to a depth of about several nanometers. Therefore, the binding force of the coating is greatly improved, and the non-ionized vaporized material atoms deposit directly on the workpiece. The sputtering of inert gas ions and coating material ions on the surface of the workpiece can also remove the contaminants to improve the bonding force.
The Advantages Of Ion Plating
1. Strong diffraction ability
In ion plating process, the particles of the evaporating material move in the direction of the power line in the form of charged ions in the electric field. Therefore, any portion where there is an electric field can obtain a good plating layer, which is superior to the ordinary vacuum coating in obtaining the plating in the direct direction. So, this method is very suitable for the coating on inner hole, the groove and the narrow slot in the plated parts. Normal vacuum coating method can only make the direct surface be coated. Evaporation particles can only be moved up like climbing ladder. But ion plating can evenly coat the back and inner holes of parts. Charged ions are able to fly along prescribed routes anywhere within their radius of activity like sitting on the helicopters.
2. High quality coatings
The ion-plated coating is dense, pinhole free, bubble free, and uniform in thickness. Even the facets and grooves can be plated evenly without metallurgy. Parts such as threads can also be plated. This method can also repair defects such as minute cracks and pits on the workpiece surface, which can effectively improve the surface quality and physical and mechanical properties of the parts being plated. Fatigue tests show that if properly handled, the fatigue life of the workpiece can be 20% ~ 30% higher than before plating.
3. Ion plating cleaning process is simplified
Most of the existing coating processes require strict cleaning of the workpiece in advance, which is complicated and costly. However, the ion plating process itself has an ion bombardment cleaning effect, and this effect continues throughout the entire coating process. The cleaning effect is excellent, and the plating can be directly brought close to the substrate, which effectively enhances the adhesion and simplifies a large amount of pre-plating cleaning work.
4. Wide range of materials can be plated
Ion plating method uses high-energy ions to bombard the workpiece surface, so that a large amount of electrical energy is converted into heat energy on the surface of the workpiece, thereby promoting the proliferation chemical reactions of surface tissue. However, the entire workpiece, especially the core of the workpiece is not affected by high temperatures. Therefore, this coating process has a wider range of applications and it is less limited. In general, various metals, alloys, and certain synthetic materials, insulating materials, heat-sensitive materials, and high-melting-point materials can be plated. It can plate non-metal or metal on metal workpieces, or metal or non-metal on non-metal workpiece, and even on plastic, rubber, quartz, ceramics, etc.