A rotating disk method is used to investigate the dissolution rate of metallic iron, nickel, and their alloys in nitric acid media. Discs 2 cm in diameter made of nickel grade N1 and Armco iron, as well as two samples with an Ni:Fe ratio of 15:85 and 50:50 are used. The effect of temperature, initial nitric acid concentration, disk rotation rate, and process duration on specimen dissolution rate are investigated. The rate is determined by the amount of dissolved metal per unit of time from a disk unit surface. Regression analysis is used to describe the effect of nitric acid concentration on specimen dissolution rate. It is found that the dissolution rate of iron metal is up to 20–60 times faster than nickel metal dissolution rate. The effect of HNO3 temperature and initial concentration when dissolving Ni and Fe alloys in nitric acid is investigated. With an increase in temperature from 303 to 353 K (HNO3 = 0.2 M, Ni:Fe = 50:50) the amount of dissolved Fe and Ni increases by a factor of 8–9. Dissolution of Ni:Fe alloy (15:85) under the same conditions results in an increase in dissolved iron by a factor of four. An increase in nickel concentration in solution occurs within 30 minutes, after which the concentration does not change. In experiments with Ni:Fe alloy = 50:50 the amount of dissolved Fe is 1.8–2.3 times greater than the amount of dissolved Ni depending on the initial acidity.
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机译：采用转盘法研究了金属铁、镍及其合金在硝酸介质中的溶解速率。使用直径 2 厘米的圆盘，由镍级 N1 和 Armco 铁制成，以及两个镍铁比为 15：85 和 50：50 的样品。研究了温度、初始硝酸浓度、圆盘旋转速率和工艺持续时间对试样溶出速率的影响。该速率由磁盘机表面每单位时间内溶解的金属量决定。回归分析用于描述硝酸浓度对试样溶出速率的影响。研究发现，铁金属的溶解速度比镍金属的溶解速度快20-60倍。研究了HNO3温度和初始浓度对Ni和Fe合金在硝酸中溶解的影响。随着温度从 303 K 升高到 353 K（[HNO3] = 0.2 M，Ni：Fe = 50：50），溶解的 Fe 和 Ni 的量增加了 8-9 倍。在相同条件下，Ni：Fe合金（15：85）的溶解导致溶解铁增加四倍。溶液中镍浓度在30分钟内增加，之后浓度不变。在 Ni：Fe 合金 = 50：50 的实验中，溶解的 Fe 量是溶解 Ni 量的 1.8-2.3 倍，具体取决于初始酸度。
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