The Corrosion Principle of Metals in Etching Machines

Metal in Etching machine The corrosion process in China first involves the dissolution of grains on the surface of metal parts, followed by dissolution at grain boundaries. Generally speaking, grain boundaries dissolve at a rate different from that of grains.

In most polycrystalline structures of metals and alloys, each crystal can adopt almost any orientation of the atomic lattice. The different orientations of grains, the size of grain density, and impurities can all form micro or micro primary cells with the surrounding parent metal. So, for metals in etching solutions, on the one hand, the presence of these primary cells creates a potential difference on the metal surface, temporarily protecting areas with positive potential and preferentially etching areas with negative potential in the etching machine. On the other hand, there are varying atomic spacings on the surface of the component, and the dissolution rate is rapid in areas with wider atomic spacings until an uneven surface is displayed. Then, the dissolution process will cut the tightly packed atomic layers at an almost constant speed, and the surface geometry will continue to change continuously as the grains dissolve. The etching on the grain boundaries will further affect the surface of the parts. The lattice distortion and enriched impurities at grain boundaries often lead to faster etching, which may cause the entire grain to be etched in a pit like manner. The smaller the grain size, the lower the surface roughness after etching, which can also be confirmed in actual production. In production, the more uniform and dense the material, the smoother its surface.

How to achieve a smooth surface of the workpiece during the etching process of the etching machine? Through Huazhou's research, it has been found that if texture etching is to be carried out, it is necessary to strengthen this microscopic local etching phenomenon. For example, controlling the appropriate acidity or alkalinity, and adding some second substances aimed at changing the etching behavior, so that the etched surface presents the desired roughening surface effect. If chemical hollowing is carried out in a corrosion machine, conditions must also be created to enhance the etching ability of the etching solution, making the etching more uniform and achieving a smooth and polished surface effect.