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-Ternary S3 electroless deposit: (a) DSC curves; (b) apparent crystallization activation energy of the first exothermic peak; (c) apparent crystallization activation energy of the second exothermic peak.
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Amorphous Ni–3.81 wt.%W–12.40 wt.%P deposit showed two crystallization exothermic peaks while amorphous Ni–12.35 wt.%P deposit presented one. Formation of the two exothermic peaks and the related influencing factors were investigated through TEM, DSC and XRD. The solid solution and pinning effect of W affected the binding of P and Ni, which induced...
Citations
... The specific heat capacity of the sample is calculated according to equation (1) [29]: From the experimentally obtained heat capacity and with use of Kirchhoff's law [30], enthalpy change was calculated. The heat of fusion was obtained in two ways. ...
Three model alloys based on Fe-C-Ni were studied containing carbon between 0.338 and 0.382 wt. % and nickel between 1.084 and 4.478 wt. %. Phase transition temperatures, heat capacity, enthalpy change, heat of fusion, coefficient of thermal expansion, and density were experimentally and theoretically determined in the high-temperature area from 1000 °C to 1595 °C. A number of techniques, namely differential thermal analysis (DTA), differential scanning calorimetry (DSC), and dilatometry, were used in this study, and the heat of fusion was determined by two approaches, that is, from the DSC peak area and from the enthalpy change. The experimental data were compared and discussed with the calculation results obtained using SW IDS, JMatPro, and Thermo-Calc operating with the commercially available TCFE8 thermodynamic database. The obtained experimental results show that the liquidus temperature and the coefficient of thermal expansion decrease with increasing nickel content. On the contrary, the density and heat of fusion values derived from the DSC peak increase with increasing nickel content. Furthermore, an ambiguous influence of nickel on the change in solidus temperature, heat capacity, enthalpy change, and heat of fusion obtained from the enthalpy change was observed.
... Electroless nickel-phosphorus (Ni-P) coatings are broadly applied to various metallic substrates to modify their surface properties, such as electrochemical behavior and hardness. This type of coating is frequently used in multiple fields, including chemical electronics, aerospace, mechanical, and oil-gas industries [1][2][3][4][5][6][7]. It has been reported that Ni-P coatings express practical anticorrosion features, wear resistance, uniformity of deposit, and high abrasion [8,9]. ...
The nickel-phosphorus (Ni-P) and nickel-phosphorus-nanodiamond (Ni-P-ND)
coatings were deposited on mild steel via electroless plating without ultrasound and
under ultrasonic agitation with different frequencies of 25, 50, 75, 100, and 150
kHz. The as-prepared coatings were characterized using scanning electron
microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray
diffraction (XRD). The corrosion performance of the fabricated layers was
evaluated in 3.5 wt% NaCl solution by electrochemical impedance spectroscopy
(EIS) and potentiodynamic polarization. Results of the corrosion tests demonstrated
that deposition under ultrasonic power provided coatings with higher stability in
the corrosive environment. The corrosion rate decreased with increasing ultrasound
frequency from 25 to 75 kHz but increased with further increase in frequency. This
introduced 75 kHz as the optimum ultrasound frequency for electroless plating of
Ni-P. It was also observed that the corrosion resistance of the proposed coating was
improved through the incorporation of 40 ppm nanodiamond into the Ni-P matrix.
... This could be explained by the formation of more than one crystalline phase. A similar curve shape was shown in the study of Ni-P-(W) coating [51]. At high heating rate, addition of W element increased the number of exothermic peaks that was explained by the crystallization of intermediate phases and the formation of stable crystal phases. ...
Thin film represents a promising alternative for the protection of metallic structures against hydrogen embrittlement and corrosion degradation. Al-Ti-W coatings were deposited by magnetron sputtering technique using three pure metallic targets. Tungsten was incorporated in Al-Ti amorphous coating with different contents ranging from 0 to 17 at% by keeping a constant Ti/Al ratio at an average of 0.8. The deposition rate was calculated in order to obtain 4 µm as an uniform film thickness. XRD, DSC and TEM analyses were performed to confirm the amorphous state of the coatings and to determine the glass transition temperature (Tg) and crystallization temperature peak (Tp). These temperatures were increased respectively from 423°C and 595°C to 490°C and 665°C with the increase of W concentration up to 17 at%. Corrosion resistance in a saline solution decreased with the increase of W content.The incorporation of W element induced an increase of the thin film hardness (H) and Young’s modulus (Er) from 9 GPa to 9.35 GPa and from 117 GPa to 131,79 GPa, respectively. The surface roughness varied with the incorporation of W that strongly influenced the coatings’ corrosion behavior. Chemical and electrochemical hydrogen charging techniques were performed to expose coated steels to hydrogen sources. W addition in the binary Al-Ti coatings strongly enhanced their resistance to hydrogen absorption. The estimated total hydrogen content trapped in the coated steel during a cathodic polarization decreased with the incorporation of W.
... Electrodeposited Ni and some of its alloys are used as model FCC materials to study the thermal stability and deformation behavior at different length scales [4][5][6][7][8][9][10][11][16][17][18][19]. There is ample literature available on electrodeposited Ni-P coatings and films [2,[20][21][22][23][24][25][26][27][28][29][30][31][32][33]. However, the effect of P content on evolution of microstructure in NC Ni under electrodeposition and thermal treatment conditions was limitedly explored. ...
... It is well established that the grain size of Ni-P electrodeposits strongly depends on the P content [3]. It has been reported that the amorphous Ni-P alloy can be produced by electrodeposition and the final structure can be a two-phase with some amorphous pockets along with the fine crystalline grains [21,[27][28][29]. However, there is some ambiguity on the critical P content required for amorphization in Ni-P electrodeposits [21,27,28]. ...
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.
... Ni, P and Mo in the obtained electroless deposit were originated from nickel sulfate, sodium hypophosphite and sodium molybdate, respectively. The two electroless plating solutions composition and plating condition were shown in Tables 1 and 2 [28]. Then, some of the deposits were heat treated in an argon atmosphere at 200 for 1 h, 8 h, 16 h, 24 h, 32 h and 48 h, at 300°C for 1 h, 4 h, 8 h and 12 h, at 400°C for 1 h, 2 h and 4 h, respectively. ...
... Solution compositions and plating conditions of amorphous Ni-P deposit[28]. ...
Amorphous Ni-4.31 wt. % Mo-12.89 wt.% P deposit and amorphous Ni-12.35 wt.% P deposit were produced by electroless deposition. The different structures were obtained by low temperature heat treatment. Effect of element Mo on microstructure evolution, thermal stability and corrosion resistance was studied by XRD and its corresponding pair density function, DSC, electrochemical examination and XPS. Results showed that adding element Mo could improve the thermal stability and amorphous tissues stability of Ni-P deposit. Furthermore, the Ni-Mo-P deposit had better corrosion resistance than the Ni-P deposit because the oxides and compounds formed by adding element Mo could effectively resist the perforation corrosion of chloride ions. The annealed Ni-Mo-P deposits with amorphous structure could form stable passivation films in neutral sodium chloride solution due to the more uniform distribution of oxides and compounds of element Mo.
... Meantime, Ni atoms could dissolve into the Cu 6 Sn 5 lattice and replace positions of Cu because of the similar diameter between Ni and Cu atoms [33]. Notably, there was a dark line detected in the IMC layer, which was suggested to be a thin Ni 2 SnP layer in previous literatures [34,35]. Typically, as reported by Zhang et al., during the aging duration, mono Ni(P) plating decomposed rapidly and transformed into Ni 2 SnP layer, and this layer was suggested porous and penetrable, thus could not suppress atomic diffusion [22]. ...
To enhance the effects of electroless Ni–P plating on inhibiting atom diffusion in Sn-58Bi joint systems, adding nano-sized metals into coating was regarded as an efficient method. Therefore, Cu nanoparticles were chosen as the additive in current study, and the interfacial microstructure evolution of solder joints by doping Cu nanoparticles into Ni(P) electroless plating were investigated. Experimental results revealed that growth rates of IMCs at the joint interface remarkably decreased with increasing content of Cu nanoparticles. In the Ni(P)–0.8 g/L Cu based joint, transformation from (Ni,Cu)3Sn4 to (Cu,Ni)6Sn5 occurred since more Cu atoms supplied by the coating participated in the interfacial reaction between solder and coating. Meantime, sizes of IMC grains at each isothermal aging stage decreased with increasing content of Cu nanoparticles, which could be attributed to introduction of potent nuclei. The IMC growth was mainly volume diffusion-controlled and followed parabolic laws. Diffusion coefficients were analyzed to be 1.18 × 10–2 μm²/h, 2.89 × 10–4 μm²/h and 2.56 × 10–4 μm²/h in Ni(P), Ni(P)–0.4 g/L Cu and Ni(P)–0.8 g/L Cu-based joint systems, respectively, suggesting that diffusion coefficient gradually decreased with increasing content of Cu nanoparticles.
... The introduction of the third elements and compounds, including Al [8], Cr [9], Mo [10], Cu [11][12][13], Al 2 O 3 [14,15], CNTs [16,17], etc., are frequently proposed to further enhance its mechanical, thermal, and chemical properties. For instance, the thermal stability of the Ni-P layer could be improved by the introduction of a third element with high melting point like W [18,19]. The addition of W atoms, even at a low level of 3 at.%, ...
Nickel–ruthenium–phosphorus, Ni–Ru–P, alloy coatings were fabricated by magnetron dual-gun co-sputtering from Ni–P alloy and Ru source targets. The composition variation and related microstructure evolution of the coatings were manipulated by the input power modulation. The as-prepared Ni–Ru–P alloy coatings with a Ru content less than 12.2 at.% are amorphous/nanocrystalline, while that with a high Ru content of 52.7 at.% shows a feature of crystallized Ni, Ru, and Ru2P mixed phases in the as-deposited state. The crystallized phases for high Ru content Ni–Ru–P coatings are stable against annealing process up to 600 °C. By contrast, the amorphous/nanocrystalline Ni–Ru–P thin films withstand a heat-treated temperature up to 475 °C and then transform into Ni(Ru) and NixPy crystallized phases at an annealing temperature over 500 °C. The surface hardness of the Ni–Ru–P films ranges from 7.2 to 12.1 GPa and increases with the Ru content and the annealing temperatures. A highest surface hardness is found for the 550 °C annealed Ni–Ru–P with a high Ru content of 52.7 at.%. The Ecorr values of the heat-treated amorphous/nanocrystalline Ni–Ru–P coatings become more negative, while with a high Ru content over 27.3 at.% the Ni–Ru–P films show more negative Ecorr values after annealing process. The pitting corrosion feature is observed for the amorphous/nanocrystalline Ni–Ru–P coatings when tested in a 3.5M NaCl solution. Severer pitting corrosion is found for the 550 °C annealed Ni–Ru–P coatings. The development of Ni(Ru) and NixPy crystallized phases during annealing is responsible for the degeneration of corrosion resistance.
Four Ti53-xZr20Nb10Cu5Be12Agx (x = 0, 1, 3 and 5 at.%) bulk metallic glass composites (BMGCs) with various size, volume fraction and morphology of in-situ crystal phase were prepared by the arc-melting method. The shear bands extensions under strain of 5% and 20% were observed to explore the contributions of in-situ crystal phase on the deformation behaviors. The results showed that addition of Ag element significantly increased the glass forming ability. When Ag addition increased from 0 to 5 at.%, the volume fraction of in-situ crystal phase decreased from 74.5% to 38.3%, the morphology transformed from the dense cluster to the spotted shape, resulting in the decrease of dendrites span length (L) and the increase of dendritic arm spacing (DAS). The size, volume fraction and morphology of in-situ crystal phase had great influence on the initiation and extensions of shear bands. In the in-situ BMGCs, the crystal phases with the appropriate size, volume fraction and morphology were conducive to the initiation of multiple shear bands and could effectively restrain the expansion of single shear band, improving the plasticity, and the in-situ BMGCs with Ag element of 3 at.% exhibited the highest plasticity of 17.9%.
A comprehensive study on the fabrication and characteristics of electroless Ni-B-W-SiC composite coating is presented. The role of tungsten in NiB matrix in improving mechanical and tribological performances is well-known. Here, the composite is formed with the incorporation of silicon carbide in Ni-B-W alloy matrix and is systematically investigated in reference to two electroless binary (NiB) and ternary (Ni-B-W) alloy coatings and Ni-B-SiC composite deposited in similar route. All coated specimens are characterized with SEM, EDS, XRD, ICP-AES, and HRTEM analyses in order to draw conclusions in comparative studies concerning morphological features, compositions, and phase structures. These coatings are also subjected to heat treatment at 450 °C for further observations. Raman spectroscopy is used to confirm the presence of SiC particles in coatings' matrix. Tribological evaluations based on results obtained from multi-pass scratch tests provided insights into characteristics evolved in the developed electroless coatings. Silicon carbide reinforcements in electroless alloy matrices (NiB, and Ni-B-W) show noticeable enhancements in microhardness, fracture toughness, and scratch resistance and those further improve on heat treatment due to the formation of harder nickel boride (Ni3B, and Ni2B) phases within crystalline coatings' matrices. Heat-treated Ni-B-W-SiC coating evolved as characteristically superior in terms of average microhardness (1141 HV0.1) and is closely followed by heat-treated Ni-B-SiC, Ni-B-W, and NiB coatings. Under different load values, heat-treated Ni-B-W-SiC composite coating exhibits higher values of scratch hardness and fracture toughness lying within a range of 10.59–10.92GPa and 4.60–4.99 MPam0.5, respectively. These values are significantly higher than all as-plated alloy and composite coatings studied here. Frictional characteristics of all developed coatings are evaluated through both progressive and multi-pass scratch tests by observing failure mechanisms observed on scratch tracks. In this study, heat-treated Ni-B-W-SiC composite coating evolved as superior in terms of mechanical and tribological characteristics.
