Effect of Passivation on the Sintering Behavior of Submicron Nickel Powder Compacts for MLCC Application

Jo, Gi-Young; Lee, Kwi-Jong; Kang, Suk–Joong L.

doi:10.4150/kpmi.2013.20.6.405

Cited by 9 publications

(2 citation statements)

References 16 publications

(14 reference statements)

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“…So obviously there was a need to assess the conductivity of Ni foils after a real sintering process. Based on the other studies on sintering Ni particles [47][48][49][50], the heating schedule of 1020 °C for 4 min was selected, and then it was confirmed that Ni particles could be successfully sintered with it. This heat treatment would be used as a criterion to evaluate the merit of the ALD coatings to preserve Ni conductivity during the sintering of Ni particles.…”

Section: Methodsmentioning

confidence: 99%

Study on the behavior of atomic layer deposition coatings on a nickel substrate at high temperature

Heidary

Randall

2016

Nanotechnology

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Although many techniques have been applied to protect nickel (Ni) alloys from oxidation at intermediate and high temperatures, the potential of atomic layer deposition (ALD) coatings has not been fully explored. In this paper, the application of ALD coatings (HfO2, Al2O3, SnO2, and ZnO) on Ni foils has been evaluated by electrical characterization and transmission electron microscopy analyses in order to assess their merit to increase Ni oxidation resistance; particular consideration was given to preserving Ni electrical conductivity at high temperatures. The results suggested that as long as the temperature was below 850 °C, the ALD coatings provided a physical barrier between outside oxygen and Ni metal and hindered the oxygen diffusion. It was illustrated that the barrier power of ALD coatings depends on their robustness, thicknesses, and heating rate. Among the tested ALD coatings, Al2O3 showed the maximum protection below 900 °C. However, above that temperature, the ALD coatings dissolved in the Ni substrate. As a result, they could not offer any physical barrier. The dissolution of ALD coatings doped on the NiO film, formed on the top of the Ni foils. As found by the electron energy loss spectroscopy (EELS), this doping affected the electronic transport process, through manipulating the Ni(3+)/Ni(2+) ratio in the NiO films and the chance of polaron hopping. It was demonstrated that by using the ZnO coating, one would be able to decrease the electrical resistance of Ni foils by two orders of magnitude after exposure to 1020 °C for 4 min. In contrast, the Al2O3 coating increased the resistance of the uncoated foil by one order of magnitude, mainly due to the decrease in the ratio of Ni(3+)/Ni(2+).

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Section: Methodsmentioning

confidence: 99%

Study on the behavior of atomic layer deposition coatings on a nickel substrate at high temperature

Heidary

Randall

2016

Nanotechnology

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“…The nickel and BaTiO 3 multilayers, and especially the Ni electrode itself, − have been studied in detail. As mentioned above, one common practice is to reduce the amount of oxygen vacancies by post-reoxidation process.…”

Section: Introductionmentioning

confidence: 99%

Redesigning Multilayer Ceramic Capacitors by Preservation of Electrode Conductivity and Localized Doping

Heidary

Randall

2016

ACS Appl. Mater. Interfaces

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Both LiCO-coated nickel particles and fast firing technique were utilized in the manufacturing of MLCCs. They preserved the conductivity of Ni electrodes and provided the possibility of sintering the devices in oxidizing atmospheres. By using our method, the partial pressure of oxygen increased from 10 atm in conventional methods to 10 atm. The oxidizing atmosphere reduced the oxygen vacancy concentration as illustrated by the color change of the samples, and the results of EELS (electron energy loss spectroscopy). A systematic test with variable parameters, LiCO coating, the sintering schedule, and the oxygen flow during sintering were executed, and the dissipation factor and the capacitance of the MLCCs were documented. Three type of MLCCs were studied: Conventional (fired with the conventional technique), Uncoated (fast fired with uncoated Ni particles), and Coated (fast fired with the coated Ni particles). The maximum oxygen activity during sintering (i.e., pO = 1.2 × 10 atm) was obtained for coated samples, and due to the minimum V concentration, their dissipation factor decreased up to 60% relative to the Conventional ones. In addition, the impedance spectroscopy, together with the map of Li ion distribution, suggested that Li ions accumulated around the electrode-dielectric interface and amplified the activation energy at these interfaces. This eventually caused the coated MLCCs to show higher capacitance than their uncoated counterparts. As a conclusion, it is shown that the manufacturing process described in this paper can provide a better MLCC with higher capacitance, and lower dissipation factor and leakage current.

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Synthesis of Ni@MgO core–shell ultrafine particles for the fabrication of thick film electrodes

Shi,

Deng,

Chen

et al. 2024

Advanced Powder Technology

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Effect of Passivation on the Sintering Behavior of Submicron Nickel Powder Compacts for MLCC Application

Cited by 9 publications

References 16 publications

Study on the behavior of atomic layer deposition coatings on a nickel substrate at high temperature

Study on the behavior of atomic layer deposition coatings on a nickel substrate at high temperature

Redesigning Multilayer Ceramic Capacitors by Preservation of Electrode Conductivity and Localized Doping

Synthesis of Ni@MgO core–shell ultrafine particles for the fabrication of thick film electrodes

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