Effect of temperature on PVD coating

PVD coating is a complex process, especially the PVD coating applied to tools and dies requires very high performance in all aspects of the coating. In the coating process, there are many factors that will affect the performance of the coating.

1. The growth of the film increases the temperature, which is conducive to improving the structure and properties of the film. At a suitable temperature of 400-600 ℃, TiN, TiAlN and other coatings will obtain better hardness and adhesion.

2. During the PVD coating process, the temperature is not linear with the adhesion, hardness, etc. The temperature is too low, the film growth is insufficient, the surface is rough, and the corrosion resistance and microhardness decrease. If the temperature is too high, coarse columnar crystals are easily formed. It causes the deterioration of the matrix material structure, the decrease of the adhesion and the decline of the film performance.

3. With the increase of substrate temperature, volatile residue can be removed, and the surface diffusion and recrystallization ability can be enhanced. The interface reaction is accelerated and impurities in the bottom layer diffuse. The substrate melts. Increase the size of crystalline particles. The coating temperature required to promote the epitaxial growth of recrystallization interface, reduce internal stress, increase step coverage, and increase the physical and chemical interaction with the substrate depends on the metallographic structure of the workpiece, heat treatment, and workpiece geometry. For example, sharp edges and thin slices are heated rapidly and temperature measurement is very difficult. Arc current, substrate bias voltage and reaction gas pressure also affect the temperature. The coating can be started at 180 ℃. The workpiece shall be coated at a temperature that will not cause physical changes in the material.

4. The PVD coating temperature exceeds the tempering point, making the workpiece soft.

5. For example, the workpiece with less parts surrounding the coating vacuum chamber will gather more plasma, which will lead to higher workpiece temperature and higher deposition rate.