Low-temperature reactive hot-pressing of cerium-doped titanate composite ceramics and their aqueous stability

Teng, Yan; Wang, Shanlin; Huang, Yi; Zhang, Kuibao

doi:10.1016/j.jeurceramsoc.2013.10.020

Cited by 37 publications

(15 citation statements)

References 30 publications

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“…The tendency of Ce to take on both tri- and tetravalent states leads to the formation of ancillary phases when targeting a single phase, such as perovskite and cerianite 19 and sphene and perovskite 20 .…”

Section: Introductionmentioning

confidence: 99%

Polymorphic Transitions in Cerium-Substituted Zirconolite (CaZrTi2O7)

Clark

Sundaram

Misture

2017

Sci Rep

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Compounds with the formulae CaZr1−xCexTi2O7 with x = 0.1–0.5 were synthesized by solid state reaction. Cerium was used as a surrogate for actinide elements. A transition from the 2M polymorph to the 4M polymorph (expanded unit cell due to cation ordering) in zirconolite was observed with increasing cerium content. The presence of both tri- and tetravalent Ce, contrary to formulation, was confirmed using X-ray absorption near edge spectroscopy, suggesting substitution on both Ca and Zr sites. Sintering was carried out via spark plasma sintering, during which the perovskite phase (Ca0.4Ce0.4TiO3) was stabilized due to the reducing conditions of this technique. Scanning electron microscopy and energy dispersive spectrometry revealed that the 2M polymorph was dilute in Ce content in comparison to the 4M-zirconolite. High temperature X-ray diffraction was used to detail the kinetics of perovskite to zirconolite transition. It was found that CaCeTi2O7 (cubic pyrochlore) formed as an intermediate phase during the transition. Our results show that a transition from 2M- to 4M-zirconolite occurs with increasing Ce content and can be controlled by adjusting the PO2 and the heat treatment temperature.

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Section: Introductionmentioning

confidence: 99%

Polymorphic Transitions in Cerium-Substituted Zirconolite (CaZrTi2O7)

Clark

Sundaram

Misture

2017

Sci Rep

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“…Some research results show that sintering temperature can greatly inuence the phase composition, microstructure, and properties of RHP products. 11,12) The present study explores its speci c effect on Ti(C,N)-TiB 2 -Co cermets.…”

Section: Introductionmentioning

confidence: 99%

Effect of Sintering Temperature on the Microstructure and Properties of Ultra-Fine Ti(C,N)-Based Cermets

Zhao

Zuo

et al. 2016

Mater. Trans.

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Ultra-ne Ti(C,N)-TiB 2 -Co cermets were fabricated from Co, Ti, C, and BN powder mixtures via a reactive hot pressing (RHP) process, and the effect of sintering temperature on their microstructure and properties was explored. An elevated temperature was conducive to the full conversion of Ti(C,N) phase, thus leading to microstructure homogenization and the production of cermets with a high relative density and purity. With increasing temperature, the relative density, hardness, and fracture toughness rst increased, and then decreased. A sample sintered at 1150 C therefore displayed the best overall performance in terms of its maximum relative density and ultra-ne particle size, with relative density, hardness, and fracture toughness of 99.9%, 1947 HV10 and 6.6 MPa.m 1/2 , respectively. Compared with P10 cemented carbide, Ti(C,N)-TiB 2 -Co displayed superior wear resistance because of its higher hardness, as well as the formation of an oxidation layer on the worn surface during dry sliding friction and wear.

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“…These monazite ceramic waste-forms were generally sintered by the conventional pressureless sintering (PLS) process, the sintering temperature is relatively high (1300-1450 1C) and holding time is relatively long (4-10 h). However, the hot-press sintering (HPS) offers several advantages over conventional methods, primarily the very low-temperature required for densification [34][35][36]. Teng et al [35] prepared Ce IV -doped titanate ceramics with relative densities over 99% by HPS at temperature as low as 1150 1C for 1-4 h and under the pressure of 30 MPa.…”

Section: Introductionmentioning

confidence: 99%

“…However, the hot-press sintering (HPS) offers several advantages over conventional methods, primarily the very low-temperature required for densification [34][35][36]. Teng et al [35] prepared Ce IV -doped titanate ceramics with relative densities over 99% by HPS at temperature as low as 1150 1C for 1-4 h and under the pressure of 30 MPa. Aloy et al [27] once prepared the 241 Am-doped monazite-(La) powder using the wet-chemistry method and investigated the incorporation of minor actinide Am (the specific activity of 2.1 Â 10 7 Bq/g) in monazite-(La) ceramic waste-forms by the HPS process.…”

Section: Introductionmentioning

confidence: 99%