Study on the Influence of Etchant Composition and Etching Process on the Precision of Stainless-Steel Microchannel and Etching Mechanism

The chemical etching method has the advantages of high precision and low cost for the preparation of steel surface microchannel, but the composition of the etching solution and the etching process have a great influence on the precision of the microstructure. In this article, the influence of etching solution composition and the etching time on the etching precision of stainless steel using a mixture of HCl and H2O2 as an etching solution is studied. The reactions and passivation processes that occur during the etching process are analyzed. The etching mechanism is revealed. The sample prepared with HCl:H2O2 = 1:2 can obtain better etching precision and high‐dimensional stability. The amount of lateral erosion and the depth of etching increases with the increase of etching time, resulting in a decrease in the etching factor and precision. Pitting and intergranular corrosion mainly occur during the etching process, and the loss of metal chloride formed in the process forms holes, which become rapid diffusion channels for corrosive Cl and O elements, and promotes the etching process. The etching reaction forms a passivation film on the surface of the substrate, which reduces the rate of the etching reaction.