Introduction of PVD coating knowledge

- Mar 06, 2019-

Introduction of PVD coating knowledge


PVD(Physical Vapor Deposition) : the process of transferring an atom or molecule from a source to the substrate surface by using a Physical process. Its role is to make some of the special properties (high strength, wear resistance, heat dissipation, corrosion resistance, etc.) of the particles sprayed on the matrix with lower performance, so that the matrix has better performance. Basic methods of PVD: vacuum evaporation, sputtering, ion plating (hollow cathode ion plating, hot cathode ion plating, arc ion plating, reactive ion plating, rf ion plating, dc discharge ion plating)


PVD technology emerged in the preparation of thin films with high hardness, low friction coefficient, good wear resistance and chemical stability and other advantages. At first, the successful application in the field of high-speed steel tools has attracted great attention from the manufacturing industry all over the world. While developing high performance and high reliability coating equipment, people have also carried out more in-depth research on the coating application in cemented carbide and ceramic tools. Compared with the CVD process, PVD process temperature is low, under 600 when the bending strength of cutting tool materials; The internal stress state of the film is compressive stress, which is more suitable for the coating of cemented carbide precision and complex tools. PVD process has no adverse impact on the environment, in line with the development direction of modern green manufacturing. At present, PVD coating technology has been widely used in the coating treatment of carbide endmill, drill bit, step drill, oil hole drill, reamer, tap, indexable milling cutter, turning blade, special-shaped cutter, welding cutter and so on.


PVD technology not only improves the bonding strength between thin film and tool matrix material, but also develops the coating composition from the first generation TiN to TiC, TiCN, ZrN, CrN, MoS2, TiAlN, TiAlCN, tin-aln, CNx, DLC and ta-c, etc. [2]


Enhanced magnetically controlled cathode arc: cathode arc technology is to complete the deposition of thin film materials under the condition of vacuum by disintegrating the target into the state of ions through low voltage and high current. The enhanced magnetron cathode arc can effectively control the arc on the surface of the target material by using the interaction of the electromagnetic field, so that the ionization rate of the material is higher and the film performance is better.


Filtered cathodic arc: filtered cathodic arc (FCA) electromagnetic filtration system, equipped with high efficient ion source can be produced by the macroscopic particles in plasma and ion mass filter clean, after magnetic filtration of sedimentary particles ionization rate was 100%, and can filter out the larger particles, so the preparation of the film is very compact and smooth, with good corrosion resistance, and the adhesion strength of the body is very strong.


Magnetron sputtering: in a vacuum environment, the target is bombarded by ionized inert gas ions through the combined action of voltage and magnetic field, resulting in the target being ejected in the form of ions, atoms or molecules and deposited on the substrate to form a film. Depending on the ionization source used, both conductor and non-conductor materials can be sputtered as target materials.


Ion beam DLC: hydrocarbon gas is ionized into plasma in the ion source. Under the combined action of electromagnetic field, carbon ion is released from the ion source. The energy of the ion beam is controlled by adjusting the voltage applied to the plasma. The hydrocarbon ion beam is directed to the substrate and the deposition rate is proportional to the ion current density. The ion beam source of the star arc coating is of high voltage, so the ion energy is larger, which makes the film and the substrate have good adhesion. The larger ion current makes the deposition speed of DLC film faster. The main advantage of ion beam technology is that it can deposit ultra-thin and multi-layer structure, the process control precision can reach several angstroms, and the defects caused by particle pollution in the process can be minimized.