Floating polished surface characteristics

(1) Surface crystallinity. The function of crystals depends on their crystal structure, and structural damage can lead to a decrease in function. Therefore, the most important quality indicator when processing single crystals is not to damage the surface crystallinity. Reflected Electron diffraction image of sapphire single crystal (1012) surface under 100kV accelerating voltage. The experimental results of polishing the surface of sapphire single crystal (1012) using various methods show that using 8 μ Surface polished with mSiC and applied with 3 μ The crystal characteristics of the surface polished with diamond have been destroyed, while both the floating polishing surface and the chemical polishing surface have obtained obvious Kikuchi lines, indicating that the crystallization of the processed surface remains basically good. Corrosion only results in internal deformation and shrinkage, while machining does not produce deformation and shrinkage, indicating that the floating polishing of single crystal materials does not produce plastic deformation. Polishing Mn Zn ferrite single crystals also achieved the same effect.

(2) Surface magnetic properties. The magnetic properties of magnetic materials are not only sensitive to organizational structure, but also to stress. Once there is residual stress on the machined surface, the magnetic properties will change. After processing the two planes of the Mn Zn ferrite circular workpiece using various methods, it was found that the floating polished surface exhibited the same magnetic properties as the chemically etched surface, indicating that there was no residual stress on its surface. 0.5 below the surface polished with Cr ₂ O Å μ There is compressive residual stress at depth m, which leads to a decrease in the initial permeability at room temperature to around 60% of the base material.

(3) Surface chemical properties. During the polishing process, the particle elements of the polishing agent invade the outermost layer of the workpiece, forming defect points. Due to the invasion of heterogeneous elements, the binding force around them becomes weaker. When polishing sapphire single crystals with different types of polishing agents, surface element analysis was performed using an IMA analyzer, and it was found that 1 μ Within m, the channeling elements containing polishing agents are clearly not a simple physical adsorption phenomenon.

Floating polished surface characteristics

Processing methods cannot remove such small defects. The type of invading elements is related to the material of the polishing agent used; If the material and purity of polishing agent are selected properly, the invasion of heterogeneous elements will not occur. For example, using SiO2 to polish sapphire substrates for SOS, or using Zn0 to polish sapphire substrates for optical waveguide. When polishing artificial crystals or optical glass, to completely avoid pollution during polishing, high-purity Si0: particles should be used as polishing agents.

Chemical corrosion is a distortion free process, but the concentration of elements on the surface of the workpiece after corrosion processing is different from the concentration inside the substrate. The surface element concentration distribution of floating polishing is similar to that of chemical etching. Therefore, it is believed that floating polishing is also a distortion free machining method similar to chemical corrosion.

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