| It has become a mature coating technology to plating nitride nano coating by multi arc ion plating.However,it is easy to produce "big particles" with diameter of 0.1 μm-10 μm while realizing high efficiency coating.The "big particle" has a strong inhibition effect on the surface performance of the coating.Reducing the proportion of "big particles" and the average diameter length has become an effective method to optimize the preparation technology of multi arc ion plating.In this paper,shielding device is added between the arc target and the substrate to prevent the deposition of "big particles".The surface morphology,texture and roughness of Ti N/TiAlN coating prepared by multi arc ion plating technology are characterized and analyzed by scanning electron microscope and XRD analyzer.The research can provide a feasible low cost preparation scheme for the optimization technology of filtering "big particles" by shielding device.The research contents are as follows:(1)A movable shield plate was placed between the cathode Ti target and Fe-Cr Based stainless steel substrate to prepare Ti N coating.In the process of changing the distance d between the shielding plate and the substrate from 10 mm to 40 mm,the proportion of coating surface,the average diameter length of large particles and the surface roughness all decrease first and then increase;the preferred orientation of Ti N(111)surface gradually increases;when D is 25 mm,the proportion,average diameter length and surface roughness of Ti N coating are the lowest in the same group,which are 1.07%,0.425 μm and 0.179 μm,respectively The film thickness increases from 2.25 μm to 2.91 μm with the increase of D,but it is significantly lower than the film thickness of 3.37 μm without shield plate,which means that the shielding effect of shield plate will lead to the decrease of deposition efficiency.(2)In order to solve the problem that the shielding plate is difficult to filter "large particles" and ensure the normal deposition efficiency,according to the different repulsive and gravitational characteristics of the negative bias grid sheath to "large particles" and metal ions,the negative bias grid is used to replace the shielding plate,and the influence of the net base spacing L and the mesh size S on the properties of TiAlN coating is explored through experiments.(3)In the experiment of TiAlN(200)multi arc ion plating with screen grid,when the distance L between screen and substrate increases from 5 mm to 45 mm,the surface roughness first decreases and then increases,the proportion and average diameter of "large particles" gradually decrease,and the preferred orientation of TiAlN(200)gradually weakens;in the aspect of filtering out "large particles" to improve the coating performance,the increase of mesh size S is closely related to the increase of distance L between screen and substrate The effect of coating is opposite.TiAlN coating with many excellent surface properties can be obtained by selecting appropriate mesh substrate spacing L and mesh size S.The experimental results show that when L = 35 mm and S = 200 μm × 200 μm,the surface roughness,the proportion of "large particles" and the average diameter of the coating are 19.6nm,6.5% and 0.74 μm,respectively,and the thickness difference between the coating and the coating without grid is less than 3%.The preferred orientation of TiAlN(200)is obvious,and the surface comprehensive properties are better. |
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