Synthesis, structure stability and magnetic properties of nanocrystalline Ag–Ni alloy

Santhi, K.; Thirumal, E.; Karthick, S.; Kim, Hee-Je; Nidhin, Marimuthu; Narayanan, V.; Stephen, A.

doi:10.1007/s11051-012-0868-7

Cited by 50 publications

(35 citation statements)

References 44 publications

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“…60 An increase in binding energy has been previously observed for small clusters of Pd, Pt, and Au. 63,64 The formation of a Sn/Ag alloy could change the binding energy of the Ag 3d 5/2 peak; 65 however, this appears unlikely due to the lack of a reducing agent for producing Sn from Sn(II). In addition, the formation of a Sn-Ag alloy is not thermodynamically favorable compared to formation of a Sn-Pd alloy in the Pd-based catalysts.…”

Section: Resultsmentioning

confidence: 99%

Electroless Copper Deposition Using Sn/Ag Catalyst on Epoxy Laminates

Uzunlar

Wilson

Kohl

2013

J. Electrochem. Soc.

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Electroless copper deposition was investigated on epoxy laminate substrates (Isola 185HR) using a silver-based catalyst, and a nonroughening surface treatment method based on sulfuric acid. The current challenges in electroless copper deposition include (i) high cost of Pd-based catalysts, (ii) deterioration of electrical performance of deposited metal at high frequency due to electron scattering at the roughened surface, and (iii) limited adhesion strength of electroless layers to substrates. We investigated an electroless copper deposition procedure composed of a H 2 SO 4 surface pretreatment, two-step Sn/Ag nano-colloidal catalyst seeding, and immersion in a traditional formaldehyde-containing electroless copper bath. The H 2 SO 4 pretreatment activated the epoxy surface for electroless deposition. Other strong acids did not lead to deposition. The H 2 SO 4 treatment cleaned the substrate and provided the adhesion of the catalyst and electroless copper without increasing the surface roughness. XPS results showed a decrease in the carbonyl groups (C=O), and acid/ester functionalities (O-C=O) at the surface. Adsorbed sulfate on the substrate from the H 2 SO 4 treatment led to Sn(II) sensitization. The tin-silver activation step resulted in Sn(IV) and Ag(0) products in the form of a Sn/Ag nano-colloidal catalyst. The Sn/Ag colloid acted as a catalyst for electroless copper deposition on the epoxy laminate substrates.

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Section: Resultsmentioning

confidence: 99%

Electroless Copper Deposition Using Sn/Ag Catalyst on Epoxy Laminates

Uzunlar

Wilson

Kohl

2013

J. Electrochem. Soc.

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“…Paramagnetic character for highly dilute solid solutions phase formed between a diamagnetic and ferromagnetic element where the ferromagnetic atom forms the solute has been well observed for bulk miscible systems such as Ni-Cu and Cu-Fe [14]. Paramagnetic character has also been reported for Ag-rich, solid solution AgNi system which is similar to the Ag-Fe system both with respect to the magnetic nature of the component element atoms and with respect to the immiscibility in the bulk state [15].The ferromagnetic component with an extremely low value of the saturation magnetization (∼0.001 emu/g) and coercively (∼30 Oe) can be due to the presence of very small amount of ferromagnetic Ag-oxide impurity on the surface of the Ag-Fe nanoparticles. It has been shown by Jo et al [16] that ∼7 nm sized Ag-Cu nanoparticles with an Ag-core and Cuoxide shell microstructure contain a paramagnetic and a ferromagnetic phase.…”

Section: Resultsmentioning

confidence: 78%

Compositionally Graded Microstructure for Ag-Fe Nanoparticles

Srivastava

Sushma

2012

Nano-Micro Lett.

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Ag-Fe nanoparticles with a highly Ag rich average composition were synthesized by the sonochemical route. Silver-iron system exhibits a wide miscibility gap in the bulk materials. Interestingly, a graded compositional profile along the nanoparticle radius was observed. Regions at and near the surface of the nanoparticle contained both Ag and Fe atoms. The composition got relatively deficient Fe towards the center of the particle with particle core made up of pure Ag. Alloying of Ag and Fe is confirmed by the absence of diffraction signal corresponding to pure Fe phase and presence of a paramagnetic phase in nanoparticles containing a diamagnetic (Ag) and ferromagnetic (Fe) elements.

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“…In the GIXRD of the as-deposited Ni 95 Cr 5 :Ag nanocomposite, Ni 95 Cr 5 -rich particles cannot be seen clearly, due to the formation of very small clusters and the metastable alloying with Ag. Although it is known that at equilibrium conditions the mutual solubility of Ni 95 Cr 5 and Ag is very low, the use of a non-equilibrium deposition process such as sputtering at room temperature allowed a substantial concentration of Ni 95 Cr 5 clusters to dissolve, forming Ni 95 Cr 5 :Ag nanocomposites;26−29 their concentration, however, was reduced after annealing, through an extensive demixing process.…”

Section: Discussionmentioning

confidence: 99%

Control of Surface Segregation in Bimetallic NiCr Nanoalloys Immersed in Ag Matrix

Bohra

Singh

Grammatikopoulos

et al. 2016

Sci Rep

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Cr-surface segregation is a main roadblock encumbering many magneto-biomedical applications of bimetallic M-Cr nanoalloys (where M = Fe, Co and Ni). To overcome this problem, we developed Ni95Cr5:Ag nanocomposite as a model system, consisting of non-interacting Ni95Cr5 nanoalloys (5 ± 1 nm) immersed in non-magnetic Ag matrix by controlled simultaneous co-sputtering of Ni95Cr5 and Ag. We employed Curie temperature (TC) as an indicator of phase purity check of these nanocomposites, which is estimated to be around the bulk Ni95Cr5 value of 320 K. This confirms prevention of Cr-segregation and also entails effective control of surface oxidation. Compared to Cr-segregated Ni95Cr5 nanoalloy films and nanoclusters, we did not observe any unwanted magnetic effects such as presence Cr-antiferromagnetic transition, large non-saturation, exchange bias behavior (if any) or uncompensated higher TC values. These nanocomposites films also lose their unique magnetic properties only at elevated temperatures beyond application requirements (≥800 K), either by showing Ni-type behavior or by a complete conversion into Ni/Cr-oxides in vacuum and air environment, respectively.

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Synthesis, structure stability and magnetic properties of nanocrystalline Ag–Ni alloy

Cited by 50 publications

References 44 publications

Electroless Copper Deposition Using Sn/Ag Catalyst on Epoxy Laminates

Electroless Copper Deposition Using Sn/Ag Catalyst on Epoxy Laminates

Compositionally Graded Microstructure for Ag-Fe Nanoparticles

Control of Surface Segregation in Bimetallic NiCr Nanoalloys Immersed in Ag Matrix

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