Search

Sodium stannate has numerous applications, including electroplating, tin alloy, catalysts, precursor to flame retardants, and also can be used as solid electrolytes and electrode materials in emerging battery systems. The primary method for producing sodium stannate typically involves the reaction between tin metal and sodium hydroxide solution. However, the procedure exhibited several limitations, such as high energy consumption, a long process flow for the production of metallic tin, as well as the release of potentially hazardous gases. Therefore, the present study focused on synthesizing sodium stannate from cassiterite minerals through alkaline pressure leaching, followed by crystallization. The main aim of this study was to examine the effect of various leaching process parameters, such as sodium hydroxide concentration, leaching temperature, and leaching time on the improvement of tin dissolution. The results showed that the alkaline pressure leaching process can successfully produce sodium stannate from the cassiterite mineral. The optimum parameters for alkaline pressure leaching to produce sodium stannate from cassiterite have been determined: temperature of 150°C, sodium hydroxide concentration of 4 mol/L, and duration of 240 minutes. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the composition of cluster ions in samples containing sodium stannate and tin(II) chloride. It has been shown that the composition of mass spectra is influenced by such parameters as the laser radiation energy and the substance content in the sample being studied. Conditions for preparing samples and recording mass spectra using these parameters were optimized. Presumptive identification of peaks in the recorded mass spectra was carried out. It has been shown that many of the ion peaks observed in the mass spectra may correspond to clusters containing tin. In the mass spectra of sodium stannate, ions of the general composition SnxOyNazHm were detected, in which the number of tin atoms reaches eight, and the maximum ion mass-to-charge ratio (m/z) is 1100. In the mass spectra of tin(II) chloride, there are ions of the general composition SnxOyHmClp and SnxCly, where the number of tin atoms reaches 4, and the highest m/z value is 1000. [ABSTRACT FROM AUTHOR]

In this investigation, combination of ammonium sulfamate (AS), sodium stannate (SS) and zinc acetate (ZA) (as external reagent) was applied by simple double bath pad-dry-cure method to acquire fire-retardancy (FR) on cotton woven fabric. This chemical combination is eco-friendly as it neither releases taxic formaldehyde nor produces any bi-hazardous corrosive gases. During preliminary study with an aim to keep total added chemical around 20–30%, optimum FR result obtained at 16%AS + 8%SS + 5%ZA with a synergistic effect. Reaction mechanism showed that proton (H+ ion) developed from AS during heating, dehydrated the cellulose causing increase in char formation and other two chemicals (SS and ZA) formed protective coating on cotton. With this optimum chemical combination, limiting oxygen index value was achieved 38.30 with char length of 6.7 cm at 45° inclined plane flammability test but there was around 30% loss of fabric tenacity. The data obtained from thermo gravimetric analysis showed change in path of pyrolysis by lowering decomposition temperature with almost 29% increase in residual char formation indicating good FR property. Surface topography analysis by SEM, functional groups by analysis of FTIR, element identification by XPS confirmed surface deposition of these chemical compound along with agglomerated precipitation of "Zinc Hydroxy Stannate". During wash stability analysis, it was found that after application of 5% ZA, wash stability was better than without ZA after 10 wash cycles. [ABSTRACT FROM AUTHOR]

Summary: Aqueous zinc batteries (AZBs) hold great promise for advancing applications in next‐generation energy storage devices because of their high safety, high energy density, and low cost. However, zinc metal anodes have greatly impeded the application in AZBs due to their poor cycle performance. Short lifespan, which is caused by dendritic growth, deformation, corrosion, and competing hydrogen evolution, is very tricky. Herein, a stable Sn@Cu foam, prepared by plating tin on copper foam, is reported as the substrate of Zn anodes. We evaluate the quality of plating tin layers, which are prepared by using different tin salt solutions, and Na2SnO3 solution is eventually selected. Electrochemical tests show that Sn@Cu foam can not only inherit the merits of Cu foam but also suppress hydrogen evolution reaction and lower the initial heterogeneous nucleation barrier of deposited Zn. Moreover, in situ observation by optical microscope demonstrates that Zn dendrite growth on Sn layer is suppressed during the plating‐stripping process. As a result, a compact Zn layer on Sn@Cu foam is obtained (Zn/Sn@Cu foam), symmetrical cells display superior cycling life of 1800 h at 1 mA cm−2 for 1 mAh cm−2, and full cells with VO2 cathode deliver remarkably better cycling stability and longer lifespan. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report on the electrochemical performance of Mg‐14Li‐3Al‐1Gd electrodes prepared by the accumulation roll bonding technique in a 0.7 M NaCl solution. To explore the effects of adding different concentrations of Na2SnO3 to 0.7 M NaCl solutions, potentiodynamic polarization, potentiostatic oxidation, electrochemical impedance spectroscopy, and scanning electron microscopy were utilized. The results show that the addition of Na2SnO3 to a 0.7 M NaCl solution increases the corrosion potential of the Mg‐14Li‐3Al‐1Gd electrodes. Samples with 0.1 mM Na2SnO3 retained the highest discharging current density and lowest polarization resistance of all the specimens. Electrodes in an electrolyte solution mixed with 0.1 mM Na2SnO3 presented a larger active reaction area, deeper channels, and higher discharging currents than those with other additive concentrations. In conclusion, to improve the electrochemical behavior of Mg‐14Li‐3Al‐1Gd electrodes in a 0.7 M NaCl solution, the optimal concentration of Na2SnO3 is 0.1 mM. [ABSTRACT FROM AUTHOR]

Abstract In this study, the ternary Ni − Sn − P alloy coatings were prepared on the copper substrate by electroless deposition at a relatively low temperature of 50 °C with a relatively high deposition rate of 9.0 μm·h−1 from a neutral solution by using sodium stannate (Na 2 SnO 3) as the tin source. The coating consisted of 96.02% Ni, 2.82% P, and 1.16% Sn. The effects of Na 2 SnO 3 and other deposition parameters on the deposition rate were investigated. Electrochemical experiments were also carried out to reveal the mechanism of Na 2 SnO 3 influencing the Ni − Sn − P deposition procedure. It was found Na 2 SnO 3 inhibited the anodic oxidation of hypophosphite and accelerated the cathodic reduction of Ni2+ simultaneously. Furthermore, the activation energy of Ni − Sn − P deposition process was estimated to be 42.6 kJ·mol−1. The Ni − Sn − P alloy coating exhibited smoother surface and improved corrosion resistance compared with Ni − P coating. Highlights • An electroless Ni-Sn-P coating was deposited in a neutral bath at 50 °C. • The tin source Na 2 SnO 3 improved the deposition rate. • Ni-Sn-P coating with the thickness of 2.25 μm contains 2.82% P and 1.16% Sn. • The mechanisum and process of low temperature deposition procedure was stated. • Ni-Sn-P coating has smoother surface and better corrosion resistance than Ni P coating. [ABSTRACT FROM AUTHOR]

The production of valuable mono- and dicarboxylic acids from abundant and renewable vegetable oil sources is of great industrial interest. It is demonstrated by a simple and eco-friendly heterogeneous catalytic system for direct oleic acid (OA) cleavage by hydrogen peroxide to produce azelaic acid (AA) and nonanoic acid (NA). Commercially available tungsten oxide was used as a heterogeneous catalyst without any modification or pretreatment, and sodium stannate was used as a H2O2 stabilizer to improve the efficiency of the oxidant. The sodium stannate additive notably improved the product yields and it could be recycled together with the tungsten oxide catalyst. Isolated product yields up to 89% for azelaic acid and 65% for nonanoic acid were achieved from oleic acid in this simple system, which should be among the best results for oleic acid cleavage in heterogeneous systems. This strategy is also applicable for other catalytic systems for the cleavage of OA or its derivatives. This work provides a potential method for the large scale upgrading of oleic acid. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sodium stannate (Na2SnO3) has been successfully prepared by a novel process of roasting cassiterite concentrates and sodium carbonate (Na2CO3) under CO−CO2 atmosphere, namely soda roasting-leaching process. However, more than 22 wt. % tin of the cassiterite was not converted into Na2SnO3 and entered the leach residues. Quartz (SiO2) is the predominant gangue in the cassiterite, and phase evolution of SnO2−SiO2−Na2CO3 system roasted under CO−CO2 atmosphere was still uncertain. In this study, the effect of SiO2 in cassiterite concentrates on preparation of Na2SnO3 was clarified. The results indicated that Na8SnSi6O18 was inevitably formed when cassiterite and Na2CO3 were roasted above 775 °C under CO−CO2 atmosphere via the reaction of SnO2 + 6SiO2 + 4Na2CO3 = Na8SnSi6O18 + 4CO2, and formation of Na8SnSi6O18 would be increased with increasing roasting temperature and Si/Sn mole fraction. In addition, it was found that Na8SnSi6O18 was insoluble in the leachate at pH value range of 1−14, which, therefore, was enriched in the leach residues. The silicon content of the cassiterite concentrates should be controlled as lower as possible to obtain a higher conversion ratio of Na2SnO3.

β-β″-AlO precursor powder was successfully prepared by a solid-phase sintering method with LiCO, NaCO (as the sources of LiO and NaO, respectively) and α-AlO powder as the raw materials. The precursor was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results indicate that the amount of NaO in the raw materials has a great effect on the formation of β″-AlO in the β-β″-AlO precursor. When NaO content is 10 wt%, the content of β″-AlO phase reaches the maximum value of 86.24 wt% in the precursor. The β-β″-AlO ceramic was prepared from β-β″-AlO precursor powder by isostatic pressing and burying sintering process. The conductive property of the β-β″-AlO ceramic was examined by electrochemical impedance spectroscopy (EIS) method, and the density was measured by the Archimedes method. The results reveal that when 10 wt% NaO was added, the sample exhibits the best performance with the lowest resistivity of 4.51 Ω·cm and the highest density of 3.25 g·cm. A solid electrolyte battery of Pt|SnO, NaSnO|β-β″-AlO|NaCrO, CrO|Pt was assembled by the β-β″-AlO electrolyte tube to measure the open potential of the resulting battery, and the formation free energy of sodium stannate was calculated. In the temperature range of 1273-773 K, the relationship between formation free energy of sodium stannate and temperature was generated as follows: $$\Delta G_{{{\text{Na}}_{ 2} {\text{SnO}}_{ 3} }}^{0 } = - 1040.83 + 0.2221T \pm 7.54$$ . [ABSTRACT FROM AUTHOR]

We report crystal growth of several rare-earth stannates RE 2 Sn 2 O 7 (RE=Pr, Tb, Ho, Dy, Yb and Lu) using the flux technique. Different combinations of flux were tried, and a Na 2 B 4 O 7 -NaF (1.2:1) mixture was found to be suitable for crystal growth. X-ray diffraction and thermal characterisation data are presented, as well as some initial measurements of magnetic and thermodynamic properties of the crystals. Little effect was observed with changing oxygen content by Sc substitution for Sn. [ABSTRACT FROM AUTHOR]

ABSTRACT Synthesis of novel amphiphilic biodegradable block copolymers based on ethylene carbonate is reported in this study. Polyethylene glycol monomethyl ether (MeO-PEO) and polyethylene glycol (PEG) of varying molar masses are used as macro-initiator for ring-opening polymerization of ethylene carbonate in the presence of sodium stannate trihydrate as a heterogeneous transesterification catalyst. Earlier elution of block copolymer from macro-initiator in size exclusion chromatography (SEC) indicated the successful synthesis of the block copolymers. Ratios of both types of blocks are varied systematically. Liquid chromatography at critical conditions is used for the analysis of the non-critical individual blocks, and if there are any critical segments that are not attached to the non-critical block. To the best of our knowledge, this is the first report on the synthesis of ethylene carbonate-based amphiphilic block copolymers. Chromatographic critical conditions of the ethylene carbonate polymer are also reported for the first time. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1887-1893 [ABSTRACT FROM AUTHOR]

The reaction of the amido-stannate LiSn(NMe2)3 with the phosphine–borane tBu2PHBH3 gives the SnII hydride [(Me2NH)2Li{BH3P(tBu)2}2Sn(H)]; the first example of a hydridic stannate(ii) that is not supported by transition metal or ligand bonding. [ABSTRACT FROM AUTHOR]

Aqueous aluminum-air batteries have attracted tremendous interest because of their inherent safety and low cost. However, their lifespan is limited by the severe self-corrosion at aluminum anode. Herein, a design strategy is presented to suppress the corrosion by modifying the aluminum/electrolyte interface. Adding hybrid additives (ellagic acid and sodium stannate) can significantly reduce the corrosion rate of aluminum anode (0.7667 mg cm−2 min−1 in the blank electrolyte and 0.3662 mg cm−2 min−1 in the electrolyte with hybrid additives). The aluminum-air full battery can achieve a higher discharge specific capacity of 2439 mAh g−1. Spectral characterization and theoretical calculation confirm that the corrosion inhibition is attributed to a composite protective film formed on the aluminum surface. This strategy has proven to be general in preventing metal corrosion. [ABSTRACT FROM AUTHOR]

In this research, the effect of the different concentrations of NaSnO as the electrolyte additive in 0.7 mol L NaCl solution on the electrochemical performances of the magnesium-8lithium (Mg-8Li) electrode are investigated by methods of potentiodynamic polarization, potentiostatic current-time, electrochemical impedance technique, and scanning electron microscopy (SEM). The corrosion resistance of the Mg-8Li electrode is improved when NaSnO is added into the electrolyte solution. The potentiostatic current-time curves show that the electrochemical behaviors of the Mg-8Li electrode in the electrolyte solution containing 0.20 mmol L NaSnO is the best. The electrochemical impedance spectroscopy results indicate that the polarization resistance of the Mg-8Li electrode decreases in the following order with the concentrations of NaSnO: 0.05 mmol L > 0.00 mmol L > 0.30 mmol L > 0.10 mmol L > 0.20 mmol L. The scanning electron microscopy studies indicate that the electrolyte additive prevents the formation of the dense oxide film on the alloy surface and facilitates the peeling off of the oxidation products. [ABSTRACT FROM AUTHOR]

Abstract: Sodium stannate is widely used in the electroplating and tin alloy industries. The traditional sodium stannate production processes suffer a variety of disadvantages including long flowsheet, high production cost and strict requirements for the equipment. In this study, a novel process for preparing sodium stannate is developed by roasting tin dioxide and sodium carbonate in CO/CO2 mixed gas followed by leaching the intermediate products in a diluted sodium hydroxide solution. The effects of roasting and leaching parameters on the leaching efficiency of Sn were investigated. The Sn leaching efficiency reaches 85.6% under the optimal experimental conditions: roasting temperature of 875°C, CO content of 15%, roasting time of 15min, Na2CO3/SnO2 mole ratio of 1.5, liquid-to-solid ratio of 4cm3/g, leaching temperature of 40°C, leaching time of 60min, and stirring speed of 300rpm. Sodium stannate trihydrate (Na2SnO3 ·3H2O) having a purity of 95.8% is successfully produced from cassiterite concentrates with a SnO2 content of 76.4% through the new process, which is superior to the traditional approach for producing the industrial first-grade stannate. [Copyright &y& Elsevier]

In this contribution, an efficient and simple two-step hybrid electrochemical-thermal route was developed for the synthesis of cubic shaped Zn2SnO4 (ZTO) nanoparticles using aqueous sodium bicarbonate (NaHCSnO3) and sodium stannate (Na2SnO3) electrolyte. The sacrificial Zn was used as anode and cathode in an undivided cell under galvanostatic mode at room temperature. The bath concentration and current density were respectively varied from 30 to 120 and 0.05 to 1.5 A/dm2. The electrochemically generated precursor was calcined for an hour at different range of temperature from 60 to 600 °C. The crystallite sizes in the range of 24-53 nm were calculated based on Debye-Scherrer equation. Scanning electron microscope and transmission electron microscopy results reveal that all the particles have cubic morphology with diameter of 40-50 nm. The as-prepared ZTO samples showed higher catalytic activity towards the degradation of methylene blue (MB) dye, and 90% degradation was found for the sample calcined at 600°C, which is greater than that of commercial TiO2-P25 photocatalysts. The photodegradation efficiency of ZTO samples was found to be a function of exposure time and the dye solution pH value. These results indicate that the ZTO nanoparticles may be employed to remove dyes from wastewater. [ABSTRACT FROM AUTHOR]

Abstract: Stannate post-treatment of as-anodized AZ31 Mg alloy was carried out in 0.4M sodium stannate 3-hydrate (Na2SnO3·3H2O) at 350K. It effectively leveled the porous anodized coating by depositing a SnO2 superficial layer with a thickness of 0.4μm. After the surface sealing, the mass transport impedance at low frequency was controlled by the ideal capacitance dispersion during the initial immersion; thus, slow corrosion kinetics was achieved. This impedance behavior might account for the ideally polarizable cathodic behavior of the electrode with overpotential. As a consequence, the stannate post-treatment afforded higher R p, E corr, and E pit values throughout the immersion in 0.1M NaCl. [Copyright &y& Elsevier]

The development of an eco friendly flame retardant (FR) has been an attractive research area for the scientists in recent years. For this purpose, sodium stannate has been investigated by few researchers as an effective eco friendly FR. In this study, the applicability of flame retardant formulated using sodium stannate (SNFR) was investigated. The SNFR has shown balanced performance properties with minimum effect on physical properties of cotton. Lowest char length of 3cm and highest LOI of 33 with strength loss of cotton in the range of 5-6% as against 10-15% of commercial FR has been achieved. Sodium stannate flame retardant (SNFR) treated cotton also offered satisfactory durability to laundering. Urea and Diammonium phosphate (DAHP) in the formulation played a great role to increase the flame retardancy of cotton however, DAHP has also negative effect on strength of cotton necessitating optimization of the recipe. [ABSTRACT FROM AUTHOR]

Abstract: Aluminum/water reaction system has gained considerable attention for potential hydrogen storage applications. In this paper, we report a new aluminum-based hydrogen generation system that is composed of aluminum/sodium hydroxide/sodium stannate solid mixture and water. This new system is characterized by the features as follows: the combined usage of sodium hydroxide and sodium stannate promoters, the use of solid fuel in a tablet form and the direct use of water as a reaction controlling agent. The factors that influence the hydrogen generation performance of the system were investigated. The optimized system exhibits a favorable combination of high hydrogen generation rate, high fuel conversion, rapid dynamic response, which makes it promising for portable hydrogen source applications. [Copyright &y& Elsevier]

Abstract: It has been shown that sodium stannate with superbasic sites generated on its surface can be obtained through simple thermal treatment of sodium stannate hydrate in pure N2. In this study, we analyzed the as-prepared materials using powder X-ray diffraction, X-ray photoelectron spectroscopy, and N2 physisorption methods. The superbasic sites were characterized by techniques of Hammett indicators and temperature-programmed desorption using CO2 as adsorbate. It was shown that after undergoing calcination at 623K, there are ample superbasic sites on sodium stannate: up to 0.254mmol/g. The superbasicity of the materials was further confirmed by employing the 1-hexene as well as cyclohexa-1,4-diene double bond isomerization reactions. The superbasicity is attributed to the higher electron-donating ability of surface O2−. The sodium stannate samples showed excellent catalytic efficiency towards selected reactions, namely the dehydrogenation of propa-2-nol, Michael addition of electron-deficient olefins, and transesterification of cyclic carbonate with methanol. It was observed that with rise of heat-treatment temperature from 573 to 623K, both superbasicity and catalytic activity increased, reaching a maximum at 623K, and then declined. It is deduced that catalytic efficiency is closely related to superbasicity of the sodium stannate catalysts. [Copyright &y& Elsevier]

Abstract: A solid superbase with H_ above 26.5 has been obtained through thermal treatment of sodium stannate hydrate. It was found to be an efficient catalyst for anti-Markovnikov hydroamination and hydroalkoxylation of electron-deficient olefins under mild conditions. [Copyright &y& Elsevier]

Abstract: A new process to obtain H2 from H2O using Al corrosion in Na2SnO3 solutions is described. Results showed an enhancement of H2 production rates using Na2SnO3 instead of NaOH at the same pH. A side reaction of Al in Na2SnO3 solutions has been found, which consumes Al to produce metallic Sn. H2 yield depends chiefly on Al/Na2SnO3 molar ratio for experiments with Na2SnO3 concentrations above 0.025M, reaching higher yields with higher Al/Na2SnO3 ratios. The maximum H2 production rates are proportional to the initially added Al mass. Two different shrinking core models for examining the kinetics of H2 generation are verified and the activation energy (Ea ) is 73±6 kJ mol−1, confirming a rate control by a chemical step. A mechanism of Al corrosion in Na2SnO3 solutions is proposed and compared with the mechanism in NaOH and NaAlO2 solutions. [Copyright &y& Elsevier]

Aerosol cloud formation may occur when certain tungsten munitions strike hard targets, placing military personnel at increased risk of exposure. Although the pharmacokinetics of various forms of tungsten have been studied in animals following intravenous and oral administration, tungsten disposition following inhalation remains incompletely characterized. The objective of this study was to evaluate the pharmacokinetics of inhaled tungstate (WO4) in rats. Male, 16-wk-old, CD rats ( n = 7 rats/time point) underwent a single, 90-min, nose-only exposure to an aerosol (mass median aerodynamic diameter [MMAD] 1.50 μm ) containing 256 mg W/m3 as radiolabeled sodium tungstate (Na2188WO4). 188W tissue concentrations were determined at 0, 1, 3, 7, and 21 days postexposure by gamma spectrometry. The thyroid and urine had the highest 188W levels postexposure, and urinary excretion was the primary route of 188W elimination. The pharmacokinetics of tungsten in most tissues was best described with a two-compartment pharmacokinetic model with initial phase half-lives of approximately 4 to 6 h and a longer terminal phase with half-lives of approximately 6 to 67 days. The kidney, adrenal, spleen, femur, lymph nodes, and brain continued to accumulate small amounts of tungsten as reflected by tissue:blood activity ratios that increased throughout the 21-day period. At day 21 all tissues except the thyroid, urine, lung, femur, and spleen had only trace levels of 188W. Data from this study can be used for development and refinement of pharmacokinetic models for tungsten inhalation exposure in environmental and occupational settings. [ABSTRACT FROM AUTHOR]

Sodium stannate/phosphate is an ideal eco-friendly flame retardant agent for cotton fabric. Development of this technique is an essential way to overcome some of its disadvantages such as the harsh feeling as a result of using high concentration of sodium stannate. Chitosan is added in the phosphorylation bath as a nitrogen source and to facilitate the phosphorylation process. Incorporation of 1% chitosan could decrease the sodium stannate concentration to the one-third of the amount that is used in the conventional method. Increasing the stannate concentration in the finishing bath from 10 to 30% could enhance the flame retardancy of the cotton fabric. Thermogravimetric analysis of the treated cotton fabric shows an increase in the residual percent of the fabric and decrease in both thermal degradation onset point (TDOP) and maximum degradation rate point as a function of stannate concentration. Increasing diammonium hydrogen phosphate (DAHP) from 2 to 10% in the finishing bath shows an increase in the residue at 500°C to 39.24%. Phosphorus and nitrogen percentages show an increase in their values till reaches to 1.39 and 1.72, respectively. The effect of curing temperature and time, chitosan concentration, and the sequence of treatment are studied in detail. [ABSTRACT FROM AUTHOR]

Abstract: Autocatalytic ternary Ni–Sn–P, Ni–W–P and quaternary Ni–W–Sn–P films were prepared using alkaline citrate-based baths and compared with binary Ni–P coatings. Energy dispersive analysis of X-ray (EDAX) showed that binary Ni–P deposit contained 11.3wt.% of phosphorus. Codeposition of tungsten in Ni–P matrix resulted in ternary Ni–W–P with 5wt.% P and 7.8wt.% of tungsten. Incorporation of tin led to ternary Ni–Sn–P deposit containing 0.4wt.% Sn and 10.3wt.% P. Presence of both sodium tungstate and sodium stannate in the basic bath had resulted in quaternary coating with 6.9wt.% W, traces of Sn and 6.4wt.% P. X-ray diffraction patterns of all the deposits revealed a single, broad peak which showed the nanocrystalline nature of the deposits. For the first time in related literature, the presence of a metastable phase Ni12P5 in ternary deposits is reported in the present study. Metallographic cross-sections of all the deposits revealed the banded/lamellar structure. Scanning electron microscopy (SEM) studies of the deposits showed smooth nodules for ternary deposits, but coarse and well-defined nodules for quaternary deposits. DSC studies of phase transformation behavior of the ternary Ni–Sn–P deposit revealed a single sharp exothermic peak at 365°C. However, ternary Ni–W–P and quaternary Ni–W–Sn–P deposits exhibited a low temperature peak at 300°C, a split type high temperature peak at 405 and 440°C and a very high temperature peak at 550°C. Higher activation energy values were obtained for W-based alloy deposits. Presence of W and Sn has helped to retain high microhardness values even at higher temperatures indicating an improved thermal stability. [Copyright &y& Elsevier]