Study On Preparation And Properties Of Nano-micro Coating With High Silicon

TiAlN is a kind of single layer coating which is commercialized and widely used. In the process of application, the coating is easy to peel off by the impact and shock. The most important reason for the coating peeling off is the film structure and the crack propagation path is too short or without barrier. Based on the above defects, TiAlSiN coating was prepared by Si element doping on TiAlN coating by glow discharge and ion sputtering technique. The microstructure of TiAIN and TiAlSiN coatings was analyzed by computer image processing technology. The physical properties of the two coatings were quantitatively described by the experimental method. The cutting performance of the uncoated tool and tools with different coating thickness under the same cutting conditions were analyzed by computer numerical simulation, theoretical calculation and experiment. Milling tests of SUS304 stainless steel with coating tools was carried out, studied the impact failure mechanism of coatings and analyzed the wear failure forms and wear mechanism. The research is of great significance for guiding the production and application of coating. The main results obtained are as follows:(1) The coating surface has droplets, pits and holes, the micro-structure of the coating is compact. The atomic percentage of TiAlSiN coating is Ti (23.58), A1 (25.95), Si (4.21), N(46.26). The doping of Si element changes the phase structure, and promotes the growth of(200) crystal orientation. The micro hardness of TiAlSiN is 37.69GPa with the adhesion strength of HF1, and the peak value of friction coefficient is about 0.36.(2)The cutting force and cutting temperature decrease firstly and then increase with the increase of coating thickness. Under the same condition, the 4?m thickness TiAlSiN coating tool has the minimum cutting force when cutting TC4 and 45 steel, and the 3?m thickness TiAlSiN coating tool has the lowest cutting temperature. The wear depth decreases with the increase of coating thickness, and the wear depth of uncoated tool is about 2-3 times than that of coating.(3) Field cutting experiments show that 4?m thickness of TiAlSiN coating tool cutting 45 steel has the minimum cutting force (498.4N). The cutting force value obtained from the cutting experiment is in agreement with the changing trend of the simulation, the deviation of the cutting test and simulation are less than 13%.(4) Under the high speed cutting condition, the service life of the TiAlSiN coating tool is 1.5 times than that of the TiAIN coating, and 5 times than that of the uncoated tool. The failure mode of the TiAlSiN coating is divided into two stages. The main failure mode of the tool is abrasive wear before the coating on the tool surface is worn out. After the TiAlSiN coating is worn out, the tool wear mode is gradually changed into adhesive wear. TiAlSiN coating is more suitable for cutting stainless steel.