Effect of sintering atmosphere on the dielectric properties of barium titanate based capacitors

Halder, N. C.; Chattopadhyay, Dipankar; Sharma, Abhijit; Saha, Dipika; Sen, Amarnath; Maiti, Himadri Sekhar

doi:10.1016/s0025-5408(01)00540-2

Cited by 30 publications

(14 citation statements)

References 13 publications

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“…However, for 7 and 10 wt.% boric acid addition, the sintered density decreased. The addition of B 2 O 3 is expected to help in liquid phase sintering [16]. However, for higher amounts of B 2 O 3 , the densification again decreased because there should be an optimum amount of liquid phase above which densification is inhibited due to the formation of a thick coating of the liquid phase around the grains [17].…”

Section: Resultsmentioning

confidence: 99%

Effect of Boron Addition on the Dielectric Properties of Giant Dielectric CaCu₃Ti₄O₁₂

et al. 2005

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Section: Resultsmentioning

confidence: 99%

Effect of Boron Addition on the Dielectric Properties of Giant Dielectric CaCu₃Ti₄O₁₂

et al. 2005

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“…Finally, dioxygen loss at elevated temperatures in low pO 2 atmospheres is expected to generate point defects (oxygen vacancies) in oxide lattices: 39,40 As a number of properties associated with oxidessuch as electrical conductivity and diffusivity of ions -are associated with lattice defects and their concentration in the bulk solid, this occurrence can alter or enhance product features.…”

Section: Sem/eds Investigationsmentioning

confidence: 99%

Synthesis of Fe/Ti oxides from a single source alkoxide precursor under inert atmosphere

Camargo¹,

Nunes²,

Luis³

et al. 2008

J. Braz. Chem. Soc.

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O alcóxido heterometálico [FeCl{Ti 2 (OPr i ) 9 }] (1) foi utilizado como um precursor de fonte única para a preparação de óxidos de Fe/Ti sob atmosfera inerte. Três procedimentos sintéticos distintos foram adotados no processamento de 1, com o emprego de soluções aquosas ácidas (HNO 3 ou HCl), ou na ausência de ácido mineral. Os produtos foram caracterizados por difratometria de raios X (pó), microscopia eletrônica de varredura combinada com espectroscopia de dispersão de raios X (MEV/EDS) e espectroscopias Raman, de ressonância paramagnética eletrônica (RPE) e Mössbauer. Os óxidos produzidos contêm titânio(IV) e ferro(III) (ou ferro(II)), dependendo das condições de reação e das temperaturas de tratamento térmico. Uma interessante redução de ferro(III) a ferro(II), que levou à obtenção de ilmenita (FeTiO 3 ), foi observada a 1000 o C no sistema contendo HNO 3 . Estudos por MEV/EDS revelaram uma distribuição altamente heterogênea dos metais em todos os produtos, possivelmente relacionada com a presença de um conteúdo significativo de carbono e de defeitos estruturais (vacâncias de oxigênio) nos sólidos.The heterometal alkoxide [FeCl{Ti 2 (OPr i ) 9 }] (1) was employed as a single source precursor for the preparation of Fe/Ti oxides under inert atmosphere. Three different synthetic procedures were adopted in the processing of 1, either employing aqueous HNO 3 or HCl solutions, or in the absence of mineral acids. Products were characterised by powder X-ray diffractometry, scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM/EDS) and Raman, electron paramagnetic resonance (EPR) and Mössbauer spectroscopies. Oxide products contained titanium(IV) and either iron(III) or iron(II), depending on reaction conditions and thermal treatment temperatures. An interesting iron(III)→iron(II) reduction was observed at 1000 o C in the HNO 3 -containing system, leading to the detection of ilmenite (FeTiO 3 ). SEM/EDS studies revealed a highly heterogeneous metal distribution in all products, possibly related to the presence of a significant content of carbon and of structural defects (oxygen vacancies) in the solids.Keywords: oxides, sol-gel, single source precursor, inert atmosphere, electron microscopy IntroductionMultimetal oxide systems play an important role in materials science. They have been extensively investigated for the development of high performance ceramics and (nano)composites, aiming at applications in optics, electronics, magnetism and catalysis. The development of structural components, energy conversion devices, sensors and MRI contrast agents has also benefited from heterometal oxide research. [1][2][3][4] Nowadays, the preparation of these oxides is often performed by chemical methods. 3,[5][6][7] In particular, the sol-gel process, either hydrolytic or non-hydrolytic, has been widely employed due to its advantages over conventional solid state methods. These advantages include lower processing temperatures and better control over microstructure, uniformity and stoichiometry o...

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“…For this purpose, smaller sized powders and cheaper base metal (particularly the Ni electrode, which has been used recently to replace Ag-Pd alloys for cost reduction) need to be used as dielectric and electrode materials, respectively. As a result, more attention must be given to the sintering process to control the shrinkage mismatch between the dielectric and electrode layers, as this is the main reason for residual stress resulting in cracking and delamination during fabrication and service [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Shrinkage Behavior and Diffusion in Ni-based Internal Electrodes with Additional Amount and Particle Size of BaTiO[sub 3] Additive

Kang¹,

Joo²,

Jung³

et al. 2008

AIP Conference Proceedings

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The effect of additional amount and particle size of BaTiOs additive on shrinkage behavior and inter-diffusion in Ni-based internal electrodes has been investigated, in order to reduce the large shrinkage mismatch between the internal electrode and the dielectric layer and to control the thermal and/or residual stresses in multilayer ceramic capacitors (MLCCs). Ni powder of 100-500 nm and two kinds of BaTiOs powders of 100 and 200 nm were used as matrix and additive, respectively. The Ni and BaTiOs powders were mixed with volume ratios of 95:5, 90:10, 85:15, respectively, and then cold-isostatic pressed. The shrinkage of starting materials and each composite was measured in a range of 700-1300°C with 150°C interval in H2/Ar atmosphere, using ASTM standard method. Diffusion phenomena at interface of Ni/BaTiOs composites with 85:15 and 90:10 volume ratios were investigated using SEM, EDX, and TEM. The particle size affects the shrinkage behavior in relatively low temperatures below 1000°C, showing a turning point at that temperature. The final shrinkage of composites is matched with that of bulk BaTiOs of smaller particle size, independent of additional amount of BaTiOs additive. A reaction layer of about 1000 nm wide is observed at the interface between the Ni and BaTiOs powders in the composite of 85:15 volume ratio. The quantitative amount of elemental Ni diffused into the BaTiOs is about 9.7 mass% in the composite of 90:10 volume ratio, without another phase seen in the Ni.

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Effect of sintering atmosphere on the dielectric properties of barium titanate based capacitors

Cited by 30 publications

References 13 publications

Effect of Boron Addition on the Dielectric Properties of Giant Dielectric CaCu₃Ti₄O₁₂

Effect of Boron Addition on the Dielectric Properties of Giant Dielectric CaCu₃Ti₄O₁₂

Synthesis of Fe/Ti oxides from a single source alkoxide precursor under inert atmosphere

Shrinkage Behavior and Diffusion in Ni-based Internal Electrodes with Additional Amount and Particle Size of BaTiO[sub 3] Additive

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Effect of sintering atmosphere on the dielectric properties of barium titanate based capacitors

Cited by 30 publications

References 13 publications

Effect of Boron Addition on the Dielectric Properties of Giant Dielectric CaCu3Ti4O12

Effect of Boron Addition on the Dielectric Properties of Giant Dielectric CaCu3Ti4O12

Synthesis of Fe/Ti oxides from a single source alkoxide precursor under inert atmosphere

Shrinkage Behavior and Diffusion in Ni-based Internal Electrodes with Additional Amount and Particle Size of BaTiO[sub 3] Additive

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Effect of Boron Addition on the Dielectric Properties of Giant Dielectric CaCu₃Ti₄O₁₂

Effect of Boron Addition on the Dielectric Properties of Giant Dielectric CaCu₃Ti₄O₁₂