Application to construction and acceleration sensor of a Fe-Ni alloyed stress impedance element by electrodeposition method.

电沉积Fe-Ni合金由于具有较高的磁导率和较小的矫顽力，已被广泛应用于磁记录薄膜磁头。近年来，Fe-Ni合金薄膜在磁致伸缩型应力传感器中的应用前景看好。这种类型的应力传感器通过使用反向磁致伸缩效应来检测加载到对象上的张力、扭矩、应力和重量，即它们的磁特性根据施加在磁性物质上的应变而变化。众所周知，Fe-Ni合金的沉积行为表现出典型的异常共沉积特征，在大多数电镀条件下，电化学非贵金属Fe优先沉积。由于Fe-Ni合金的磁性能随其成分的变化而变化很大，因此必须稳定沉积固定成分的Fe-Ni合金以保持其所需的性能。因此，弄清F-…的异常沉积机制具有重要意义在硫酸盐溶液中进行了不同电镀条件下Fe-Ni合金的沉积，并与锌铁系金属合金的沉积行为进行了比较，结果表明：Fe-Ni合金的沉积行为表现出典型的异常共沉积特征，在大多数电镀条件下，Fe-Ni合金的沉积行为优先于电化学非贵金属Fe的沉积。Fe-Ni合金共沉积过程中的异常共沉积行为明显依赖于溶液的pH缓冲能力。这可能是由于在水合铁族金属离子的多级还原过程中，FeOH+的离解常数比NiOH+的离解常数要小得多，所以FeOH优先吸附在较贵重的Ni的沉积位置上。在延缓FeOHad形成的电镀条件下，FeOH的优先程度降低了。较少

Electrodeposited Fe-Ni alloys have been widely used for the thin film head of magnetic recording because of their high magnetic permeability and small coercive force. In recent years, the application of Fe-Ni alloy films to the stress sensor of magnetostriction type has been expected. This type of stress sensors detect the tension, torque, stress and weight loaded to the subject by using the reverse magnetostrictive effect that their magnetic property changes depending on the strain applied to magnetic substances. It has been well known that the deposition behavior of Fe-Ni alloys showed a typical feature of anomalous codeposition, in which electrochemically less noble Fe deposits preferentially under most plating conditions. Since the magnetic properties of Fe-Ni alloy change greatly depending on its composition, the alloy of fixed con position should be deposited stably to keep the desired properties. Therefore, it is important to make clear the mechanism of anomalous deposition of F … More e-Ni alloys.Deposition of Fe-Ni alloys was performed under various plating conditions in the sulfate solutions and the deposition behavior was compared with that of Zn-iron-group metal alloy, The results obtained are described as follows.The deposition behavior of Fe-Ni alloys showed a typical feature of the anomalous codeposition, in which electrochemically less noble Fe deposits preferentially under most plating conditions. This anomalous codeposition was caused by the suppression of Ni deposition due to the codeposition of Fe.The anomalous codeposition behavior in Fe-Ni alloy deposition was evidently dependent on the pH buffer capacity of the solutions. This can be explained in term of the preferential adsorption of FeOH on the deposition sites of more noble Ni due to the extremely smaller dissociation constant of FeOH+ than NiOH+ in the multi-step reduction process of hydrated iron-group metal ions.The degree of the preferential of less noble Fe was decreased under the plating conditions that the formation of FeOHad retarded.The magnetic coercive force of the deposited alloy films depends remarkably on their chemical composition as well as on their crystal grain size. Less