Study On Films Deposited In Internal Holes By Arc Ion Plating

At present, depositing film in internal holes is an important problem in the field of surface engineering, which is needed to be solved immediately. The difficulty in technology is that plasma can't be transported in internal holes efficiently, which results in the small deposition depth and poor film quality. Enhancing the density of plasma in the hole could improve the quality of deposited films. The density of plasma in holes can be efficiently enhanced by pulling plasma into the hole. The film with high quality can be obtained, which could improve the life of the workpieces with internal holes. Plasma is very sensitive to the magnet field. The deposition parameters also greatly influence the plasma behaviors. In this paper, on the basis of external magnet field and the form of pulsed bias, study on the film deposition in internal holes is conducted in order to pulling plasma into holes.Three experiments are designed and carried out. The first one is depositing TiN film in the internal hole of blind tube with the size of 50mm×200mm×5mm. The tube is applied with direct current bias, pulsed bias and pulsed with magnet field respectively. The second experiment is depositing DLC film in the internal hole of square mould with the size of 10mm×10mm×50mm. The mould is applied with pulsed bias and permanent magnet in order to investigate the influence on the film deposition in holes. The last experiment is making a plasma diagnosis. The diagnosis is carried out to identify the influence on the film deposition in internal holes induced by the variation in density of plasma due to the additional magnet fields.The experimental results show that for those TiN films deposited in the internal holes with more than 20GPa hardness, the ratios of depth and diameter reach 1:1,1.4:1 and 2:1 respectively under the condition of direct current bias, pulsed bias and pulsed with magnet field. For those DLC films deposited in the internal holes with no obvious decrease in thickness, the ratio of depth and diameter gets to 2.0 under the condition of additional magnet field, which is enhanced by 30%. The density of plasma in the chamber under the condition of no magnet field is 4.2×1010 cm-3, and the density of plasma increases to 9.2×1010 cm-3 by adding the magnet field. It explains that adopt the optimization of magnetic field and pulsed bias can lead to plasma to improve the coating quality.