Simultaneous Enhancement of Mechanical and Magnetic Properties in Extremely-Fine Nanograined Ni-P Alloys

Abstract

Exploring structural effects that influence both the mechanics and magnetism in nanocrystalline materials, particularly extremely-fine nanograined ones with grain sizes down to several nanometers, is of high interest for developing multifunctional materials combining superior mechanical and magnetic performances. We found in this work that electrodeposited extremely-fine nanograined Ni-P alloys exhibit a significant enhancement of magnetization, simultaneously along with an increase in hardness, after low-temperature annealing. The relaxation of non-equilibrium structures, precipitation of the second phase and the segregation of P atoms to grain boundaries (GBs) during annealing have then been sequentially evidenced. By systematically comparing the variations in macroscopic and microstructural investigation results among several Ni-P alloys with different P contents, we suggest that the second phase has little effect on magnetization enhancement, and essentially both the structural relaxation and GB segregation can play important roles in hardening by governing GB stability, and in the improvement of magnetization by enhancing Ni–Ni atom exchange interactions.

Study of adsorption of Congo red on ferric oxide@straw magnetic composites

“…The maximum adsorption rate of Congo red by MMCS and MCS reached the maximum adsorption rate at the initial concentration of 10 mg/L of Congo red dye, respectively. When the concentration of Congo red continued to increase, the active sites were fully occupied and thus no longer adsorbed excess Congo red ions[9], resulting in a lower adsorption rate. Therefore, both MCS and MMCS are suitable for the adsorption of Congo red solution with lower concentration, and 40 mg/L of Congo red solution was selected because the change in the removal rate of Congo red solution after the initial concentration of 30 mg/L was small.…”