| Since the end of the 20th century, Material surface treatment and surface modification technology develops rapidly. Vacuum ion plating technology is one of the most advanced and widely used surface treatment technologies. The hard coatings deposited by Multi arc ion plating technology is widely used on account of its excellent structure and mechanical properties. The TiN coating is still the main measures to prevent the surface of high speed cutting tools. But, the oxidation temperature of TiN coating is only 500℃. Polybasic alloy compound coating has been widely researched to improve the oxidation temperature. Compared with TiN, TiAlSiN coatings have higher hardness and oxidation temperature. Besides, the mixed element Si restricts the growth of the columnar crystal in TiAIN coatings. TiAlSiN coatings are expected to become better protective coatings. The deposition technologies mainly include hollow cathode arc ion plating, magnetron sputtered ion platting and multi arc ion plating. Multi arc ion plating technology has many advantages, such as high ionization rate, high coating quality and simple device. There are many parameters in the process of deposition such as deposition temperature, N2 flow and pulse voltage. The spatial distribution of magnetic field affects the distribution of plasma on the surface of the target. Based on above reasons, the influence of deposition temperature, N2 flow and pulse voltage on the properties of TiAlSiN coatings was studied.(1) An orthogonal experiment was designed with the influencing factors of deposition temperature, nitrogen flow and bias. The process parameters were optimized according to the result of orthogonal experiment. The TiAlSiN coating deposited by optimized parameters had better performance. The content of Ti, Al, Si and N atom was 21.31%, 23.51%,4.37% and 50.81%. The ingredient of macroparticles is Ti. The diffusion layer between coating and substrate improved the adhesion of coating. The hardness and adhesion was 39.56GPa and 31.16N.(2) We studied the influences of deposition temperature on the coating performances. With the deposition temperature increased from 200℃ to 400℃, the amount of macroparticles decreased. When the deposition temperature is 300℃, the amount of macroparticles is the least. The adhesion increased with the increase of deposition temperature. The particle reactivity was motivated due to the high deposition temperature. The internal coating crystallization condition was improved which the XRD verifies the result.(3) We studied the influences of N2 flow on the coating performances. With the N2 flow increased from 100sccm to 200sccm, the amount of macroparticles decreased because of the increase of impact between reaction particles. The hardness decreased obviously when the N2 flow greater than 175sccm. The adhesive force decreased with the increase of N2 flow on account of the higher content of N.(4) We studied the influences of pulse bias voltage on the coating performances. With the bias voltage increased from 200V to 600V, the amount of macroparticles decreased obviously. The hardness and adhesive force increased firstly and decreased then. When the voltage was 400V the hardness and adhesive force was 38.60GPa and 30.66N respectively. The crystallized status was promoted with the increase of bias voltage.(5) The pulse magnetic field assist multi arc ion plating was employed to deposit TiAlSiN coatings. When the filed current was 2.5 A and 20Hz, the amount and diameter of macroparticles were decreased obviously. The hardness and adhesive force was 38.56Gpa and 29.80N respectively. The arc presented a series of concentric circles and shaked ceaselessly. The field had a strong constraint effect on the movement of arc spot. |
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