Particle size effects on the thermal conductivity of ZnO

Bo, Espen Drath; jesen,; So, Martin; ndergaard,; Christensen, Mogens; Iversen, Bo B.

doi:10.1063/1.4731565

Cited by 5 publications

(3 citation statements)

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“…The relative densities of all ZnO ceramics are more than 85%, demonstrating the feasibility of SPS‐TLP in the fabrication of ZnO ceramics. Figure 11C,D shows the densities of ZnO ceramics prepared by different sintering process (SPS‐TLP, FAST/SPS‐with water, SPS, CSP, CSP‐High pressure, and Flashing‐CSP) as functions of sintering temperatures and pressures, respectively 62–71 . Compared with SPS and Flashing‐CSP, SPS‐TLP yields dense ZnO ceramics at lower temperatures, which is lowered by 250–700°C.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 11C,D shows the densities of ZnO ceramics prepared by different sintering process (SPS-TLP, FAST/SPS-with water, SPS, CSP, CSP-High pressure, and Flashing-CSP) as functions of sintering temperatures and pressures, respectively. [62][63][64][65][66][67][68][69][70][71] Compared with SPS and Flashing-CSP, SPS-TLP yields dense ZnO ceramics at lower temperatures, which is lowered by 250-700 • C. Compared with FAST/SPS-with water, CSP, and CSP-high pressure, the applied pressure during SPS-TLP is reduced from several hundred MPa to ≤50 MPa. Hence, SPS-TLP exhibits excellent advantages in fabricating high dense ZnO ceramics at low sintering temperatures (200-300 • C) with low applied pressures of 3.8-50 MPa.…”

Section: Mw-tlp Of Cawo 4 Ceramicsmentioning

confidence: 99%

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Hybrid low‐temperature sintering processes of electro‐ceramics

Li,

Fu,

et al. 2023

J Am Ceram Soc.

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Cold sintering process (CSP) developed recently has attracted much attention due to the ultralow sintering temperatures and high efficiencies with the assist of transient liquid phase (TLP). Based on CSP, we have further established a protocol for low‐temperature sintering processes by combining TLP with other sintering technologies, including hybrid sintering process with microwave and TLP (MW‐TLP), and hybrid sintering process with spark plasma sintering and TLP (SPS‐TLP). Three typical electro‐ceramics (TiO2, CaWO4, and ZnO) are selected, which are highly densified (>97%) with excellent electrical properties at reduced sintering temperatures, applied pressures or holding times, demonstrating the feasibility of MW‐TLP and SPS‐TLP in fabricating electro‐ceramics. Especially, the Q × f value of TiO2 ceramics (38,020 GHz) prepared by MW‐TLP at 1000°C is 46.2% and 23.4% higher than that of microwave and spark plasma sintered samples, respectively, and comparable to traditional thermal sintered (TTS) samples at 1300–1400°C. The dielectric properties of MW‐TLP CaWO4 ceramics sintered at 900°C for 2 h are comparable to TTS samples sintered at 1000–1300°C for 2–5 h. ZnO ceramics can be highly densified (∼98%) by SPS‐TLP with mild sintering conditions (200–300°C and 3.8–50 MPa) compared to SPS (>500°C) and CSP (>100 MPa). The frameworks of fundamental mechanisms are outlined together with the experimental data. It is expected that this work will provide promising sintering methods to fabricate electro‐ceramics and offer inspirations on sintering combinations to develop low‐temperature sintering processes with high efficiencies.

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Section: Resultsmentioning

confidence: 99%

Section: Mw-tlp Of Cawo 4 Ceramicsmentioning

confidence: 99%

Hybrid low‐temperature sintering processes of electro‐ceramics

Li,

Fu,

et al. 2023

J Am Ceram Soc.

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“…Density (Kg/m 3 ) 998.2 999 5,240 [28] 5,460 [29] Viscosity (mPa.s) 1.0005 1.108 N/A N/A Thermal conductivity (W/m.K) 0.6435 [30] 0.8259 [30] 13.55 [31] 23.73 [28] Specific heat (J/Kg.K) 4,181 [32] 4,181.80 [32] 628.3 [29] 495.20 [28]…”

Section: Tap Water Spring Water Fe2o3 Znomentioning

confidence: 99%

Design of Nanofluid-Based Spring Water/Tap Water and Nanoparticles of Fe2O3/ZnO as a Coolant for the Engines

Faisal,

Abdullah Mohammed

2023

DJES

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In this work, an experimental system was established to measure the heat transfer characteristics, including the heat transfer coefficient, overall heat transfer, Nusselt number, and thermal conductivity. The investigation focused on spring water and tap water-based nanofluids containing Fe2O3 and ZnO nanoparticles with particle sizes of 50 nm and 70 nm, respectively. The experiments were conducted inside an automobile engine, studying the effects of varying nanoparticle volume fractions at a constant temperature. Fe2O3 and ZnO concentration in the respective based fluids was verified between 0.02 % and 0.08 % v/v and 0.01 and 0.07 %, respectively. The spring water is not so far used in the previous studies and is much more available in Kurdistan region. Reynolds numbers of nanofluids inside the engine were considered between 1000 to 8000 in a different range as that of the literature review. Reynolds analogy for heat and momentum has been employed in this study. It was observed that the thermo-physio-mechanical properties of nanofluids increased with increase in the concentration of nanoparticles and Reynolds number. However, the friction factor decreased with increasing Reynolds number but increased with an increasing volume concentration of nanoparticles. Generally, the results showed that the enhancement of the effective heat transfer of the nanofluids reached 46%, the overall heat transfer coefficient reached 39%, thermal conductivity reached 21.35% and Nusselt number reached to 38%. at 0.08% volume fraction of Fe2O3/spring water nanofluid. Based on all previous parameters estimated, the designed nanofluids in this study could be classified as a workable nanofluid in many industry applications

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