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Tantalum electrolytic capacitors have performance advantages of long life, high temperature stability, and high energy storage capacity and are essential micro-energy storage devices in many pieces of military mechatronic equipment, including penetration weapons. The latter are high-value ammunition used to strike strategic targets, and precision in their blast point is ensured through the use of penetration fuzes as control systems. However, the extreme dynamic impact that occurs during penetration causes a surge in the leakage current of tantalum capacitors, resulting in a loss of ignition energy, which can lead to ammunition half-burst or even sometimes misfire. To address the urgent need for a reliable design of tantalum capacitor for penetration fuzes, in this study, the maximum acceptable leakage current of a tantalum capacitor during impact is calculated, and two different types of tantalum capacitors are tested using a machete hammer. It is found that the leakage current of tantalum capacitors increases sharply under extreme impact, causing functional failure. Considering the piezoresistive effect of the tantalum capacitor dielectric and the changes in the contact area between the dielectric and the negative electrode under pressure, a force–electric simulation model at the microscale is established in COMSOL software. The simulation results align favorably with the experimental results, and it is anticipated that the leakage current of a tantalum capacitor will experience exponential growth with increasing pressure, ultimately culminating in complete failure according to this model. Finally, the morphological changes in tantalum capacitor sintered cells both without pressure and under pressure are characterized by electron microscopy. Broken particles of Ta–Ta2O5 sintered molecular clusters are observed under pressure, together with cracks in the MnO2 negative base, proving that large stresses and strains are generated at the micrometer scale. ARTICLE HIGHLIGHTS: HIGHLIGHTS • The failure phenomenon of a notable surge in leakage current in two commonly used tantalum capacitors under dynamic impact is investigated. • A mechanical–electrical model for tantalum capacitor electrodes is established at the microscale, and we the complete failure of tantalum capacitors under higher impacts is anticipated. • Morphological changes in tantalum capacitor sintered cells both without pressure and under pressure are characterized by electron microscopy, and it is proved that large stresses and strains are generated at the micrometer scale. [ABSTRACT FROM AUTHOR]

Glass properties play crucial roles in ensuring the safety and reliability of electronic packaging. However, challenges, such as thermal expansion and resistance to acid corrosion, pose long-term service difficulties. This study investigated the impact of the microstructure on acid resistance by adjusting the glass composition. A glass material with excellent acid resistance was obtained by achieving a similar coefficient of thermal expansion to tantalum; it exhibited a weight loss rate of less than 0.03% when submerged in 38% sulfuric acid at 85 °C for 200 h. Theoretically, this glass can be used to seal wet Ta electrolytic capacitors. Differential scanning calorimetry (DSC) was used to analyze the glass transition temperature and thermal stability of borosilicate glasses. X-ray diffractometry (XRD), scanning electron microscopy (SEM), and Raman spectroscopy were used to study the microstructure of the amorphous phase of the borosilicate glass, which revealed a close relationship between the degree of network phase separation in the borosilicate glass and the degree of polymerization (isomorphic polyhedron value, IP) of the glass matrix. The IP value decreased from 3.82 to 1.98 with an increasing degree of phase separation. Boron transitions from [BO4] to [BO3] within the glass network structure with increasing boron oxide content, which diminishes the availability of free oxygen provided by alkaline oxide, resulting in a lower acid resistance. Notably, the glass exhibited optimal acid resistance at boron trioxide and mixed alkaline oxide contents of 15% and 6%, respectively. Raman experiments revealed how the distributions of various bridging oxygen atoms (Qn) affect the structural phase separation of the glass network. Additionally, Raman spectroscopy revealed the depolymerization of Q4 into Q3, thereby promoting high-temperature phase separation and highlighting the unique advantages of Raman spectroscopy for phase recognition.

Glass properties play crucial roles in ensuring the safety and reliability of electronic packaging. However, challenges, such as thermal expansion and resistance to acid corrosion, pose long-term service difficulties. This study investigated the impact of the microstructure on acid resistance by adjusting the glass composition. A glass material with excellent acid resistance was obtained by achieving a similar coefficient of thermal expansion to tantalum; it exhibited a weight loss rate of less than 0.03% when submerged in 38% sulfuric acid at 85 °C for 200 h. Theoretically, this glass can be used to seal wet Ta electrolytic capacitors. Differential scanning calorimetry (DSC) was used to analyze the glass transition temperature and thermal stability of borosilicate glasses. X-ray diffractometry (XRD), scanning electron microscopy (SEM), and Raman spectroscopy were used to study the microstructure of the amorphous phase of the borosilicate glass, which revealed a close relationship between the degree of network phase separation in the borosilicate glass and the degree of polymerization (isomorphic polyhedron value, IP) of the glass matrix. The IP value decreased from 3.82 to 1.98 with an increasing degree of phase separation. Boron transitions from [BO4] to [BO3] within the glass network structure with increasing boron oxide content, which diminishes the availability of free oxygen provided by alkaline oxide, resulting in a lower acid resistance. Notably, the glass exhibited optimal acid resistance at boron trioxide and mixed alkaline oxide contents of 15% and 6%, respectively. Raman experiments revealed how the distributions of various bridging oxygen atoms (Qn) affect the structural phase separation of the glass network. Additionally, Raman spectroscopy revealed the depolymerization of Q4 into Q3, thereby promoting high-temperature phase separation and highlighting the unique advantages of Raman spectroscopy for phase recognition. [ABSTRACT FROM AUTHOR]

The necessity for urban mining of metals has arisen due to the growing demand for metals brought about by technological innovation, the depletion of natural resources, and the exponential growth in e-waste generation. However, to be industrially adaptable, any recycling process must be economically profitable. Therefore, in this article, an economic feasibility study was conducted to determine the profitability of the proposed recycling process for recovering valuable metals from waste tantalum capacitors. Firstly, an integrated process was developed for the recovery of almost all economically and strategically significant metals. A detailed elemental and metallurgical balance followed this to determine the mass flow of metals during various stages of treatment. Lastly, the economic feasibility analysis has been done by estimating various cost components from capital and operating costs (utilizing Indian cost as foundation for calculation) to evaluate the profit that might be made by operating the suggested recycling facility for a month. Sensitivity and scenario analysis further investigated the impact of the most significant cost component on the percentage profit. The findings of this study support the notion that the suggested recycling method has a great deal of potential value and is commercially feasible with an ample profit margin. [ABSTRACT FROM AUTHOR]

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The major advantage of Polymer Tantalum capacitors over other types of tantalum capacitors is their low equivalent series resistance (ESR), providing a higher capacitance stability with frequency and ripple current capability. When Polymer Tantalum capacitors were introduced to the market in mid 1990s, they were low voltage, leaky, and unreliable, which limited their applications to commercial electronics. Today, some types of polymer tantalum capacitors demonstrate the highest working voltage, lowest DC leakage, and highest reliability ever achieved in tantalum capacitors. These Polymer Tantalum capacitors combine outstanding performance and reliability with superior volumetric charge efficiency, which makes them cost effective and attractive for numerous applications, including mission critical ones. This paper is dedicated to the major technological breakthroughs and scientific discoveries that enabled the radical evolution of Polymer Tantalum capacitors. [ABSTRACT FROM AUTHOR]

In this work, different types of polymer and MnO2 cathode capacitors are tested for scintillation breakdown using a constant current stress (CCS) technique modified to allow detection of amplitudes and duration of current spikes. Monitoring of leakage currents with time under bias is used to assess the effect of scintillations. The appearance and composition of damaged sites are examined after deprocessing and cross-sectioning. Thermal processes during scintillations are analyzed, a mechanism of breakdown based on growth of conductive filaments in the dielectric is suggested, and self-healing processes in polymer and MnO2 cathode capacitors is discussed. [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.)

The performance degradation trend of a tantalum capacitor has different characteristics in different degradation regimes with different temperatures and humidity. Clustering method and degradation trend analysis can be useful for early warning of life. In this paper, according to the degradation characteristics of the capacitance and the dissipation factor with different temperature and humidity, the experiment is designed, and the failure mechanisms of different degeneration regimes are analyzed. After the ordered clustering method is introduced, using the natural property and the change rate α(k) of the slope β(k) of the error function δ[p(m,k)], the determination method of the optimization clustering number is put forward. The Davies‐Bouldin Index is proposed as the evaluation method of the ordered clustering result, and the validation of the evaluation method was verified by the degradation data with other stresses. For the stable degradation regime, the degradation trend analysis is completed. The error result shows that the degradation fitting functions can be a good fit for the degradation trend with different stress. According to the degradation fitting analysis, the degradation prediction method is described to find the relationship between prediction life and different temperature and humidity to realize the failure time prediction with different stresses using the early degradation data. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [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.)

The major advantage of Polymer Tantalum capacitors over other types of tantalum capacitors is their low equivalent series resistance (ESR), providing a higher capacitance stability with frequency and ripple current capability. When Polymer Tantalum capacitors were introduced to the market in mid 1990s, they were low voltage, leaky, and unreliable, which limited their applications to commercial electronics. Today, some types of polymer tantalum capacitors demonstrate the highest working voltage, lowest DC leakage, and highest reliability ever achieved in tantalum capacitors. These Polymer Tantalum capacitors combine outstanding performance and reliability with superior volumetric charge efficiency, which makes them cost effective and attractive for numerous applications, including mission critical ones. This paper is dedicated to the major technological breakthroughs and scientific discoveries that enabled the radical evolution of Polymer Tantalum capacitors.

Contrary to conventional tantalum capacitors with MnO2 cathodes, chip polymer tantalum capacitors (CPTCs) might degrade in both high humidity and dry environments. A better understanding of the kinetics of moisture content variations in CPTCs is necessary to determine bake-out conditions for the parts before soldering to avoid pop-corning failures and to select adequate preconditioning before reliability and qualification testing. In this paper, ac characteristics in different types of CPTCs have been studied with time during moisture sorption and desorption at temperatures from room to 125 °C. Capacitance increased with moisture content from minimal to maximal values reproducibly. This allowed using tantalum slugs as humidity sensors and measurements of capacitance variations with time to describe processes of moisture diffusion. A model that relates characteristic times of capacitance variations with the size of the case and moisture characteristics of polymer materials has been developed. Temperature dependencies of the characteristic times follow Arrhenius law with activation energy in the range from 0.4 to 0.5 eV. The equivalent series resistance (ESR) remained relatively stable during environmental testing, but dissipation factors (DFs), reached maximum and increased more than 10 times at characteristic times of moisture accumulation or release. The phenomena have been explained by changes in the charge absorption processes caused by variations of the barrier at the conductive polymer/Ta2O5 interface with moisture content. [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.)

The article discusses the accelerated method of analysis the electrolytic tantalum capacitors quality on the basis of the change equivalent series resistance forecast while conducting the STRESS TEST.

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.)

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.)

Tantalum capacitor demand is rapidly growing, primarily from the electronic and superalloy industries. Indeed, the global tantalum market is anticipated to boost at a compound annual growth rate of around 6% over the next decade. With increasing technological advancements, electronics' obsolescence rate has also increased. The obsolete capacitors from these electronics are a rich secondary resource for recycling strategically and economically significant metals. In this article, we have developed an environment-friendly hydrometallurgical route for recovery of manganese and nickel from the tantalum capacitors. Firstly, silica-free tantalum capacitor procured after pre-processing was leached using hydrochloric acid (1–3 M) for preferred dissolution of manganese and nickel, to facilitate a tantalum-rich residue. Manganese was then selectively separated from leach liquor using solvent extraction with D2EHPA and CYANEX272, with the extraction efficiency of each reagent compared. Quantitative dissolution of both manganese (99.9%) and nickel (98.9%), with no tantalum dissolution, was witnessed under the optimized leaching condition of 3 M HCl, 50 g/l pulp density, 60 °C, and 120 min. Kinetic data for manganese and nickel in the temperature range of 30–60 °C demonstrated the leaching reaction at the surface to be the rate controlling step. D2EHPA and CYANEX272 each showed excellent selectivity for manganese under the optimized conditions. However, CYANEX272 proved to be a better extractant in light of higher extraction efficiency in single-stage extraction (∼75%), than D2EHPA (∼40%), with less organic consumption. Above 99% manganese was selectively extracted with predicted 2-stages extraction by McCabe-Thiele plot using CYANEX272 under the optimized condition. [Display omitted] • An effective and cleaner method for Mn and Ni recovery from Ta capacitors, isolating Ta into the residue, is presented. • 3 M HCl, 60 °C, 120 min, 50 g/l pulp density is optimal parameters for quantitative Mn and Ni dissolution with no Ta loss. • Kinetic data for Mn and Ni demonstrated the leaching reaction at the surface to be the rate controlling step. • CYNAX272 found to be a better extractant than D2EHPA with better extraction efficiency (>99%) of Mn in 2-stage extraction. [ABSTRACT FROM AUTHOR]

Previous study has demonstrated that field crystallization of anodic tantalum oxide (ATO) films is associated with large in-plane compressive stresses that evolve in several characteristic stages. The mechanism(s) associated with this stress evolution are not well defined, and the impact of these stresses on the field crystallization process requires further understanding. This work reports investigations of the stress evolution that are designed to evaluate contributions from hydration of the amorphous Ta oxide (ATO), electrostriction and crystal growth. Stresses were monitored in situ with a multi-beam optical technique, to elucidate these different contributions. Measurements were conducted during exposure to the acid electrolyte with and without an applied field, and also during different growth stages. The stress evolution mechanisms include contributions from reactions with the electrolyte (hydration), electrostriction and growth of amorphous and crystalline oxides. In addition, a strong linear correlation between stress evolution and crystal growth was established during longer exposure to electric field. [ABSTRACT FROM AUTHOR]

Abstract: Amorphous, anodically grown tantalum pentoxide serves as a dielectric layer in capacitors using anodes constructed from tantalum. These capacitors are extensively used in demanding high-reliability applications such as military, aerospace and medical systems. One of the degradation mechanisms in this oxide layer is crystallization induced by applied electric fields. Previous studies have described many attributes of this process. However, the role of stress and strain in the crystallization process has not been explicitly studied to date. The purpose of the present study is to directly monitor the stress evolution and understand its role in the field-induced crystallization of anodic tantalum oxide (ATO). To this end, tantalum was deposited onto quartz substrates by electron beam evaporation and subsequently anodized in acidic electrolytes. A multi-beam optical technique was then used for the in situ measurement of stress evolution in the anodic thin films during the application of electric fields whose strengths are on the order of 5.5×106 V/cm. The salient features of field-driven crystallization in acidic electrolytes were additionally tracked using microscopy. The results indicate that field-induced crystallization of ATO is associated with compressive stresses. The methods used in the present study offer a promising new approach for a detailed mechanistic understanding of the stresses associated with the field crystallization process in ATO. [Copyright &y& Elsevier]

The effect of compressive mechanical stresses on chip solid tantalum capacitors is investigated by monitoring the characteristics of different part types under axial and hydrostatic stresses. An exponential increase of leakage currents was observed when stresses exceeded a critical value, which varied on average from 10 to 40 MPa depending on the part type. For the first time, reversible variations of leakage currents (up to two orders of magnitude) with stress have been demonstrated. Mechanical stresses did not cause significant changes of ac characteristics of the capacitors, whereas breakdown voltages measured during the surge-current testing decreased substantially, indicating an increased probability of failures of stressed capacitors in low-impedance applications. Variations of leakage currents are explained by a combination of two mechanisms: stress-induced scintillations and stress-induced generation of electron traps in the tantalum pentoxide dielectric. [ABSTRACT FROM PUBLISHER]

Tantalum electrolytic capacitors have been on the market for more than half a century, in a range of applications. However, the most common design uses MnO 2 as the electrolyte, which can be thermodynamically unstable and, upon failure, can damage the circuit. To mitigate this risk, an alternative to the MnO 2 electrolyte was developed using conductive polymers. Compared to MnO 2 , polymer Ta capacitors are more resilient to surge current, have a lower equivalent series resistance, and are ignition-free. However, polymer electrolytes are susceptible to degradation at high temperature and humidity. This paper presents an experimental study of polymer Ta capacitors from two different manufacturers, tested under six different environmental conditions, and characterized electrically at intervals during those tests. A time-to-failure model was developed to predict the degradation as a function of temperature and humidity. • The primary failure modes for polymer Ta capacitors under elevated temperature and humidity conditions were studied. • The effect of bias with the life of polymer Ta capacitors under different environmental conditions was studied. • A life model that correlates the effects of temperature and relative humidity was developed. [ABSTRACT FROM AUTHOR]