Effect of Mg substitution on microstructure and electrical properties of Mn1.25Ni0.75Co1.0−x Mg x O4(0 ≤ x ≤ 1) NTC ceramics

et al. 2021

J Adv Ceram

Self Cite

The Mn1.95−xCo0.21Ni0.84SrxO4 (MCNS) (0 ≼ x ≼ 0.15) based negative temperature coefficient (NTC) materials are prepared by co-precipitation method. The replacement of Mn by Sr plays a critical role in controlling the lattice parameter, relative density, microstructure, and electrical properties. The lattice parameter and relative density increase with the increase of Sr content. A small amount of Sr restrains the grain growth and increases the bulk density. Moreover, the room resistivity ρ25, material constant B25/50, activation energy Ea, and temperature coefficient α values of MCNS ceramics are influenced by the Sr content and ranged in 1535.0–2053.6 Ω·cm, 3654–3709 K, 0.3149–0.3197 eV, and (−4.173%)–(−4.111%), respectively. The X-ray photoelectron spectroscopy (XPS) results explain the transformation of MCNS ceramics from n- to p-type semiconductors. The conduction could arise from the hopping polaron between Mn3+/Mn4+ and Co2+/Co3+ in the octahedral sites. The impedance data analysis also discusses the conduction mechanism of the MCNS ceramic, whereas grain resistance dominates the whole resistance of the samples. Furthermore, the aging coefficient (ΔR/R) of MCNS ceramics is found to be < 0.2%, which indicates the stable distribution of cations in the spinel. Finally, the MCNS ceramics demonstrate excellent thermal durability with < 1.3% of resistance shift after100 thermal shock cycles.

Section: Aging Performance and Thermal Shock Cyclingmentioning

confidence: 99%

Enhanced aging and thermal shock performance of Mn1.95−xCO0.21Ni0.84SrxO4 NTC ceramics

et al. 2021

J Adv Ceram

Self Cite

“…The addition of Sr forms the oxygen vacancies and decreases the concentration of cationic vacancies at the grain boundaries. Consequently, the inhibition of cationic vacancies diffusion significantly improves aging performance [48,49]. XRD patterns of A0 ceramic have been recorded during aging after 0 h, 1000 h and 100 thermal shock cycles.…”

Section: R R /  = mentioning

confidence: 99%

Enhanced aging and thermal shock performance of Mn1.95-xCo0.21Ni0.84SrxO4 NTC ceramics

et al. 2020

Preprint

Self Cite

Herein, the Mn1.95-xCo0.21Ni0.84SrxO4 (MCNS) (0 ≤ x ≤ 0.15) based negative temperature coefficient (NTC) materials are prepared by co-precipitation method. The replacement of Mn by Sr plays a critical role in controlling the lattice parameter, relative density, microstructure and electrical properties. The lattice parameter and relative density increase with the increase of Sr content. A small amount of Sr restrains the grain growth and increases the bulk density. Moreover, the ρ25, B25/50, Ea and α values of MCNS ceramics are influenced by the Sr content and ranged from 1535.0-2053.6 Ω·cm, 3654-3709 K, 0.3149-0.3197 eV and -4.111--4.173%, respectively. The XPS results explain the transformation of MCNS ceramics from n- to p-type semiconductors. The conduction could arise from the hopping polaron between Mn3+/Mn4+ and Co2+/Co3+ in the octahedral sites. Furthermore, the aging coefficient (△R/R) of MCNS ceramics is found to be < 0.2%, which indicates the stable distribution of cations in the spinel. Finally, the MCNS ceramics demonstrate excellent thermal durability with <1.3% of resistance shift after 100 thermal shock cycles.

“…The addition of Sr decreases the concentration of cationic vacancies at the grain boundaries. Consequently, the inhibition of cationic vacancies diffusion significantly improves aging performance [50,51]. XRD patterns of A0 ceramic have been recorded during aging after 0 h, 1000 h and 100 thermal shock cycles.…”

Section: R R /  = mentioning

confidence: 99%

Enhanced aging and thermal shock performance of Mn1.95-xCo0.21Ni0.84SrxO4 NTC ceramics

et al. 2020

Preprint

Self Cite

Herein, the Mn1.95-xCo0.21Ni0.84SrxO4 (MCNS) (0 ≤ x ≤ 0.15) based negative temperature coefficient (NTC) materials are prepared by co-precipitation method. The replacement of Mn by Sr plays a critical role in controlling the lattice parameter, relative density, microstructure and electrical properties. The lattice parameter and relative density increase with the increase of Sr content. A small amount of Sr restrains the grain growth and increases the bulk density. Moreover, the ρ25, B25/50, Ea and α values of MCNS ceramics are influenced by the Sr content and ranged from 1535.0-2053.6 Ω·cm, 3654-3709 K, 0.3149-0.3197 eV and -4.111--4.173%, respectively. The XPS results explain the transformation of MCNS ceramics from n- to p-type semiconductors. The conduction could arise from the hopping polaron between Mn3+/Mn4+ and Co2+/Co3+ in the octahedral sites. The impedance data analysis also discussed the conduction mechanism of the MCNS ceramic, while grain resistance dominates the whole resistance of the samples. Furthermore, the aging coefficient (△R/R) of MCNS ceramics is found to be < 0.2%, which indicates the stable distribution of cations in the spinel. Finally, the MCNS ceramics demonstrate excellent thermal durability with <1.3% of resistance shift after 100 thermal shock cycles.