The passivation behavior of a medium-entropy alloy (MEA) CoCrNiZr_x (x = 0.1, 0.2 and 0.3) in 0.1 M H₂SO₄ solution was investigated. The roles of Zr in alteration of microstructure, electrochemical characteristics, and passive film chemistry of CoCrNi alloy were evaluated. With the addition of Zr element, the phase structure changes from a single face-centered cubic (FCC) phase to a two-phase structure, with the appearance of Zr-rich HCP phase. The addition of Zr accelerates the degradation process of MEAs in 0.1 M H₂SO₄, resulting in the increase of anodic current and carrier density and decrease of the film resistance as determined by the electrochemical impedance spectroscopy and Mott-Schottky results. The preferential dissolution of the Zr-rich phase (high thermodynamic activity), the weak compactness of the Zr oxides, the depletion of the Cr oxides, and the increase in carrier density are responsible for the degradation of the Zr-alloying CoCrNi alloy in 0.1 M H₂SO₄.

研究了中等熵合金 (MEA) CoCrNiZr _x ( x  = 0.1、0.2 和 0.3) 在 0.1 MH ₂ SO ₄溶液中的钝化行为。评估了 Zr 在改变 CoCrNi 合金的微观结构、电化学特性和钝化膜化学方面的作用。随着Zr元素的加入，相结构从单一的面心立方（FCC）相转变为两相结构，并出现了富Zr的HCP相。Zr的加入加速了MEA在0.1 MH ₂ SO _{4 中}的降解过程，导致阳极电流和载流子密度的增加以及由电化学阻抗谱和莫特-肖特基结果确定的薄膜电阻的降低。富Zr相的优先溶解（高热力学活性）、Zr氧化物的弱致密性、Cr氧化物的消耗以及载流子密度的增加是Zr合金CoCrNi合金在0.1时降解的原因MH ₂ SO ₄。