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通过在化学转化溶液中加入纳米Al_2O_3颗粒、SiO_2颗粒及SiO_2溶胶,利用化学转化的方法在35CrMnSi钢表面形成一层化学转化膜,研究纳米硬质相对转化膜微观结构的影响。结果表明,纳米硬质相的加入对化学转化膜的微观结构有明显的影响,纳米Al_2O_3的加入使磷酸锌由片状晶体变成球形或椭圆形的晶粒,晶粒尺寸减小,转化膜的结构更加致密;纳米SiO_2显著影响了磷酸锌晶体的生长取向,使其由垂直或倾斜于基体表面的片状晶体变成了平行于基体生长的扇形晶体。另外,通过在转化溶液中加入SiO_2溶胶引入SiO_2硬质相的方法克服了传统纳米颗粒在转化液中易团聚、难分散的问题。
By adding nano Al 2 O 3 particles, SiO 2 particles and SiO 2 sol to the chemical conversion solution, a chemical conversion coating is formed on the surface of 35CrMnSi steel by chemical conversion to study the influence of the nano-hardness on the microstructure of the conversion coating. The results show that the addition of nano-hard phase has a significant influence on the microstructure of the chemical conversion coating. The addition of nano-Al 2 O 3 transformed the zinc phosphate into a spherical or oval grain from the lamellar crystal, The structure of nanocrystalline SiO 2 has a significant influence on the growth orientation of zinc phosphate crystals, and the nanocrystalline SiO 2 crystals change from sheet crystals perpendicular or inclined to the substrate surface to fan crystals parallel to the substrate growth. In addition, the method of introducing the SiO 2 sol into the conversion solution by introducing the SiO 2 hard phase overcomes the problem that the traditional nanoparticles are easily aggregated and difficult to disperse in the conversion solution.