Free-standing nanocrystalline (NC) nickel-phosphorous (Ni–P) alloy foils with P content in the range of 0.2–5.0 wt percent are synthesized by pulsed electrodeposition technique. The aim of the present study is to evaluate the effect of P content on the hardness and microstructural evolution in Ni–P alloys during both electrodeposition and thermal treatment. The microstructure, hardness and thermal analysis of the alloys are investigated using electron microscopy, nanoindentation and differential scanning calorimetry (DSC), respectively. This study demonstrates that there is localized structural heterogeneity in conjunction with significant grain refinement in the alloys containing excessive P content beyond its solid solubility. Nanohardness measurements indicate that both the grain refinement and internal strain induced by codeposition of P solute atoms affect the strengthening of Ni matrix. The exothermic peaks observed in the DSC thermograms are found to be strongly dependent on P content in the alloy and these are associated with structural relaxation, formation of metastable and stable nickel phosphide phases along with concurrent grain growth and particle coarsening. The grain growth kinetics study showed that in Ni–P alloys Smith-Zener drag mechanism involving control of grain boundary mobility by Ni₃P nanoparticles overtakes the solute drag effect of P with increasing temperature.

通过脉冲电沉积技术合成了P含量在0.2-5.0 wt％范围内的自立纳米晶（NC）镍-磷（Ni-P）合金箔。本研究的目的是评估电沉积和热处理过程中P含量对Ni-P合金硬度和显微组织演变的影响。分别使用电子显微镜，纳米压痕和差示扫描量热法（DSC）研究了合金的显微组织，硬度和热分析。这项研究表明，在含有超过固溶度的过量P的合金中，存在局部结构异质性和明显的晶粒细化。纳米硬度测量表明，P溶质原子共沉积引起的晶粒细化和内部应变均会影响Ni基体的强化。发现在DSC热分析图中观察到的放热峰强烈依赖于合金中的P含量，这些峰与结构弛豫，亚稳态和稳定的磷化镍相的形成以及同时的晶粒生长和颗粒粗化有关。晶粒生长动力学研究表明，在Ni-P合金中，Smith-Zener阻力机制涉及通过Ni控制晶界迁移率 形成亚稳和稳定的磷化镍相，同时出现晶粒长大和颗粒粗化。晶粒生长动力学研究表明，在Ni-P合金中，Smith-Zener的阻力机制涉及通过Ni控制晶界迁移率 形成亚稳和稳定的磷化镍相，同时出现晶粒长大和颗粒粗化。晶粒生长动力学研究表明，在Ni-P合金中，Smith-Zener的阻力机制涉及通过Ni控制晶界迁移率随着温度的升高，₃ P纳米颗粒超过了P的溶质拖曳效应。