Experimental study on the evolution process of Zr702 microdimple array generated with masked jet electrochemical machining

Zirconium is a prospective metal to replace stainless steel in nuclear energy, aerospace, medicine, and chemical fields owing to its excellent comprehensive properties. However, microfabrication of zirconium metal by existing machining methods suffers from severe tool wear, low machining efficiency, and poor machining quality. Electrochemical machining has advantages for processing zirconium metal microstructures, but related studies have been rarely reported due to superpassivation of zirconium. The aim of this study was to evaluate the feasibility and processing trends of masked jet electrochemical machining of Zr702 sheet microdimple array. The dissolution behavior of Zr702 was analyzed in different concentrations of sodium nitrate and polyaluminum chloride electrolytes. The electrolyte was optimized, and the electrochemical corrosion mechanism of Zr702 was explained. Then, the effect of main processing parameters, including the mask aperture, machining gap, electrolyte pressure, jet scan speed, and pulse voltage, on machining performance was investigated in detail. After optimizing the parameters, a good synthesized quality of microdimple array was obtained with an average diameter of 157.60 μm, an average depth of 79.25 μm, a depth/diameter ratio of 0.503, a lateral corrosion coefficient of 2.043, a diameter variable coefficient of 1.72, and a depth variable coefficient of 2.90.