More Like this

1. Distribution and Cycling of Nickel and Nickel Isotopes in the Pacific Ocean

   https://doi.org/10.1029/2024GL111115  

   Bian, X; Yang, S‐C; Raad, R J; Odendahl, C E; Lanning, N T; Sieber, M; Huang, K‐F; Fitzsimmons, J N; Conway, T M; John, S G (August 2024, Geophysical Research Letters)

   Abstract Nickel stable isotopes (δ⁶⁰Ni) provide insight to Ni biogeochemistry in the modern and past oceans. Here, we present the first Pacific Ocean high‐resolution dissolved Ni concentration and δ⁶⁰Ni data, from the US GEOTRACES GP15 cruise. As in other ocean basins, increases in δ⁶⁰Ni toward the surface ocean are observed across the entire transect, reflecting preferential biological uptake of light Ni isotopes, however the observed magnitude of fractionation is larger in the tropical Pacific than the North Pacific Subtropical Gyre. Such surface ocean fractionation by phytoplankton should accumulate isotopically lighter Ni in the deep Pacific, yet we find that North Pacific deep ocean δ⁶⁰Ni is similar to previously reported values from the deep Atlantic. Finally, we find that seawater dissolved δ⁶⁰Ni in regions with hydrothermal input can be either higher or lower than background deep ocean δ⁶⁰Ni, depending on vent geochemistry and proximity. 

   more » « less
2. The biogeochemical balance of oceanic nickel cycling

   https://doi.org/10.1038/s41561-022-01045-7  

   John, Seth G.; Kelly, Rachel L.; Bian, Xiaopeng; Fu, Feixue; Smith, M. Isabel; Lanning, Nathan T.; Liang, Hengdi; Pasquier, Benoît; Seelen, Emily A.; Holzer, Mark; et al (November 2022, Nature Geoscience)
3. On the Fabrication of Defect-Free Nickel-Rich Nickel–Titanium Parts Using Laser Powder Bed Fusion

   https://doi.org/10.1115/1.4054935  

   Zhang, Chen; Xue, Lei; Atli, Kadri C.; Arróyave, Raymundo; Karaman, Ibrahim; Elwany, Alaa (September 2022, Journal of Manufacturing Science and Engineering)

   Abstract Laser powder bed fusion (L-PBF) additive manufacturing (AM) is an effective method of fabricating nickel–titanium (NiTi) shape memory alloys (SMAs) with complex geometries, unique functional properties, and tailored material compositions. However, with the increase of Ni content in NiTi powder feedstock, the ability to produce high-quality parts is notably reduced due to the emergence of macroscopic defects such as warpage, elevated edge/corner, delamination, and excessive surface roughness. This study explores the printability of a nickel-rich NiTi powder, where printability refers to the ability to fabricate macro-defect-free parts. Specifically, single track experiments were first conducted to select key processing parameter settings for cubic specimen fabrication. Machine learning classification techniques were implemented to predict the printable space. The reliability of the predicted printable space was verified by further cubic specimens fabrication, and the relationship between processing parameters and potential macro-defect modes was investigated. Results indicated that laser power was critical to the printability of high Ni content NiTi powder. In the low laser power setting (P < 100 W), the printable space was relatively wider with delamination as the main macro-defect mode. In the sub-high laser power condition (100 W ≤ P ≤ 200 W), the printable space was narrowed to a low hatch spacing region with macro-defects of warpage, elevated edge/corner, and delamination happened at different scanning speeds and hatch spacing combinations. The rough surface defect emerged when further increasing the laser power (P > 200 W), leading to a further narrowed printable space. 

   more » « less
4. Changing the polarization and mechanical response of flexible PVDF-nickel ferrite films with nickel ferrite additives

   https://doi.org/10.1016/j.mseb.2022.115815  

   Sapkota, Bedanga; Martin, Alix; Lu, Haidong; Mahbub, Rifat; Ahmadi, Zahra; Azadehranjbar, Soodabeh; Mishra, Esha; Shield, Jeffrey E.; Jeelani, Shaik; Rangari, Vijaya (September 2022, Materials Science and Engineering: B)
5. The Role of Carbon Content: A Comparison of the Nickel Particle Size and Magnetic Property of Nickel/Polysiloxane‐Derived Silicon Oxycarbide

   https://doi.org/10.1002/adem.202201453  

   Yang, Ni; Zhang, Xuanyi; Reynolds, Lewis; Kumah, Divine; Xu, Chengying (January 2023, Advanced Engineering Materials)

   A facile and novel processable method to synthesize the Ni nanoparticles (Ni NPs) by tailoring their size in the matrix of the silicon oxycarbide (SiOC) ceramic system is reported. This method is based on polymer‐derived ceramics (PDCs), instead of the conventional powder route. The specific structural characteristics and magnetic properties of the various Ni NPs/SiOC composites as a function of carbon content are systematically investigated. The magnetic properties are experimentally investigated as a function of NP size and measurement temperature. It is demonstrated that the change in the size of Ni NPs (average from ≈4 to ≈ 19 nm) determines the magnetic nature of superparamagnetism. Zero‐field‐cooled (ZFC) and field‐cooled (FC) magnetization studies under magnetic fields of 100 Oe are performed. The saturatedMversusH(M–H) loops (saturation magnetization) increase and the coercivity decreases with the size reduction of Ni NPs. It is an indicator of the presence of superparamagnetic behavior and single‐domain NP for ceramic materials. 

   more » « less