Roadmap for densification in cold sintering: Chemical pathways

Ndayishimiye, Arnaud; Sengul, Mert Y.; Sada, Takao; Dursun, Sinan; Bang, Sun Hwi; Grady, Zane A.; Tsuji, Kosuke; Funahashi, Shuichi; Duin, Adri C. T. van; Randall, Clive A.

doi:10.1016/j.oceram.2020.100019

Cited by 52 publications

(31 citation statements)

References 77 publications

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“…Cold sintering process (CSP) is an innovation for the low‐temperature sintering that has developed rapidly in recent years 1–9 . It takes the advantage of mediate liquid phase with or without pressure to facilitate the densification below 300°C and now has been successfully applied in a wide variety of materials such as BaTiO 3 , SiO 2 , Al 2 O 3 and TiO 2 10–14 .…”

Section: Introductionmentioning

confidence: 99%

The effects of cold sintering parameters on the densification of Na₂WO₄ ceramics using Na₂WO₄·2H₂O dry powders

Hao

Guo

et al. 2022

J Am Ceram Soc.

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Cold sintering process (CSP) combines transient liquid phase and/or external pressure to assist the densification of ceramics, the sintering mechanism of which is typically dominated by the “dissolution–precipitation” process. In this work, Na2WO4·2H2O dry powders without liquid water have been used as the “liquid phase” to realize the densification of Na2WO4 ceramics. The effects of sintering parameters on the CSP of Na2WO4 ceramics using Na2WO4·2H2O dry powders are systematically studied, including sintering temperature, external pressure, sintering process time and the amount of Na2WO4·2H2O phase. It is found that the “liquid phase,” that is, Na2WO4·2H2O is the key factor for controlling the CSP of Na2WO4 ceramics, and Na2WO4·2H2O hydrate shows an advantage of homogeneous dispersion of liquid water. The sintering temperature affects the densification mechanism involved with plastic deformation and the “dissolution–precipitation,” external pressure accelerates the densification process, and enough sintering process time ensures the completion of CSP. Finally, the optimum cold sintering parameters of Na2WO4 ceramics by Na2WO4·2H2O powders are obtained at 150°C and 240 MPa for 60 min with a pretreatment at 150°C for 30 min.

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Section: Introductionmentioning

confidence: 99%

The effects of cold sintering parameters on the densification of Na₂WO₄ ceramics using Na₂WO₄·2H₂O dry powders

Hao

Guo

et al. 2022

J Am Ceram Soc.

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“…Sada et al 35 have shown that by using transient chemistry such as a Ba(OH) 2 octahydrate, the densification of BaTiO 3 by cold sintering can occur at a significantly reduced temperature and time of 225°C and 1 h. Recently, several chemical pathways for cold sintering have been described wherein upon cold sintering, the final product either: (1) retains the chemical composition or phase of the starting powders (e.g., ZnO, magnetite), (2) has a different chemical composition or phase than the starting powders (e.g., α-quartz), or (3) results in a new compound or chemical doping (e.g., BaTiO 3 cold sintered with BaOH 2 •8H 2 O or SrOH 2 •8H 2 O). 36 In this work, lead acetate (PbAc) trihydrate is explored as a sintering aid to densify PZT by CSP. This approach is "water-free" in that only the structural water is used in the densification process.…”

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confidence: 99%

Comparison of different sintering aids in cold sinter‐assisted densification of lead zirconate titanate

et al. 2021

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Various processing methods such as hydrothermal sintering, 1 spark plasma sintering, 2,3 microwave sintering, 4 liquid phase sintering, 5 and cold sintering 6 have been developed in an effort to lower sintering temperatures for bulk ceramics. In many of these approaches, a secondary liquid phase, often called a sintering aid, is used to lower processing temperatures significantly 7-9 via a liquid phase sintering mechanism. For example, compounds such as Cu 2 O/PbO, V 2 O 5 , P 2 O 5 , or LiBiO 2 facilitate densification of lead zirconate titanate (PZT) ceramics at <1000°C; without such liquid phases, PZT is typically sintered at 1200-1300°C. [10][11][12][13] Gutmanas et al. 14 first coined the term "cold sintering" in 1983 to refer to a plastic deformation in metals at low temperatures by utilizing extremely high uniaxial pressure: ~GPa's. Recently, the cold sintering process (CSP) has enabled densification of a number of ceramic materials at temperatures of 25-300°C in the presence of a transient liquid phase and applied uniaxial pressure: ~100 to 500 MPa (in an open system). 15 A broad range of material chemistries and material structures including metal oxides, 16 inorganic salts, 17 composites, 18,19 and multilayer systems 20 have been

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“…The ability to sinter all types of materials to high densities enables unique incorporation of very different material with new types of interfaces, avoiding the chemical decompositions and interactions that lead to deleterious reactions occurring in traditional co-sintering at high temperatures. Cold sintering offers new pathways to integration with careful thought to the appropriate transient chemical phases that drive the transport processes necessary to enable fast and effective densification of different materials [57,58]. In the cold sinter-assisted densification of PZT, Wang et al achieved 89% relative density in the cold sintering step [59].…”

Section: Processingmentioning

confidence: 99%

Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

et al. 2021

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Medical ultrasound and other devices that require transducer arrays are difficult to manufacture, particularly for high frequency devices (>30 MHz). To enable focusing and beam steering, it is necessary to reduce the center-to-center element spacing to half of the acoustic wavelength. Conventional methodologies prevent co-sintering ceramic–polymer composites due to the low decomposition temperatures of the polymer. Moreover, for ultrasound transducer arrays exceeding 30 MHz, methods such as dice-and-fill cannot provide the dimensional tolerances required. Other techniques in which the ceramic is formed in the green state often fail to retain the required dimensions without distortion on firing the ceramic. This paper explores the use of the cold sintering process to produce dense lead zirconate titanate (PZT) ceramics for application in high frequency transducer arrays. PZT–polymer 2-2 composites were fabricated by cold sintering tape cast PZT with Pb nitrate as a sintering aid and ZnO as the sacrificial layer. PZT beams of 35 μm width with ~5.4 μm kerfs were produced by this technique. The ZnO sacrificial layer was also found to serve as a liquid phase sintering aid that led to grain growth in adjacent PZT. This composite produced resonance frequencies of >17 MHz.

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Roadmap for densification in cold sintering: Chemical pathways

Cited by 52 publications

References 77 publications

The effects of cold sintering parameters on the densification of Na₂WO₄ ceramics using Na₂WO₄·2H₂O dry powders

The effects of cold sintering parameters on the densification of Na₂WO₄ ceramics using Na₂WO₄·2H₂O dry powders

Comparison of different sintering aids in cold sinter‐assisted densification of lead zirconate titanate

Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

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Roadmap for densification in cold sintering: Chemical pathways

Cited by 52 publications

References 77 publications

The effects of cold sintering parameters on the densification of Na2WO4 ceramics using Na2WO4·2H2O dry powders

The effects of cold sintering parameters on the densification of Na2WO4 ceramics using Na2WO4·2H2O dry powders

Comparison of different sintering aids in cold sinter‐assisted densification of lead zirconate titanate

Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

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The effects of cold sintering parameters on the densification of Na₂WO₄ ceramics using Na₂WO₄·2H₂O dry powders

The effects of cold sintering parameters on the densification of Na₂WO₄ ceramics using Na₂WO₄·2H₂O dry powders