Cover Image, Volume 100, Issue 11doi: 10.1111/jace.14536pmid: N/A
The YSZ coils/springs fabricated using non solvent‐induced phase inversion based on liquid rope coiling principle. The geometric dimensions and mechanical properties can be controlled and tailored. This method can be used for the large‐scale production of ceramic coils/springs in hundreds of micrometer scale. Top: schematic of the experiment design; Bottom left: Optical images of green YSZ coils and Bottom right: A SEM image of the cross section of sintered YSZ coils. (Photo credits: Xing C, Yi M, Wang G, Guo F, et al. A simple approach to manufacture ceramic coils based on liquid rope coiling effect. https://doi.org/10.1111/jace.15076.)
Poly(methacrylate)‐derived diblock dispersant for TiO2 in aqueous suspensionsLi, Chia‐Chen; Chang, Shinn‐Jen; Wu, Chi‐Wei; Chang, Cha‐Wen
doi: 10.1111/jace.15039pmid: N/A
In this paper, we propose a newly designed dispersant, ammonium poly(methacrylate)‐block‐poly(2‐phenoxyethyl acrylate) (PMA‐b‐PBEA), and our rheological and zeta potential test results verify its superior dispersion efficiency for aqueous suspensions in comparison to the commercial dispersant ammonium polyacrylate (PAA‐NH4). The extremely high dispersion efficiency of PMA‐b‐PBEA correlates closely to its diblock structure, which simultaneously exhibits a less polar anchoring head group and a water‐dissociable stabilizing moiety. The unique structure of PMA‐b‐PBEA accounts for its high powder adsorption effectiveness, which is demonstrated in its adsorption capability being double that of PAA‐NH4.
In‐situ measurements of lattice expansion related to defect generation during flash sinteringLebrun, J.‐M.; Hellberg, C. S.; Jha, S. K.; Kriven, W. M.; Steveson, A.; Seymour, K. C.; Bernstein, N.; Erwin, S. C.; Raj, R.
doi: 10.1111/jace.15071pmid: N/A
We report results from in‐situ measurements of lattice expansion during flash sintering of 3 mol% yttria stabilized tetragonal zirconia taken at the Advanced Photon Source, Argonne National Laboratory. The expansion is anisotropic, with the relative expansion of the a‐lattice constant exceeding that of the c‐lattice constant. The anisotropic expansion cannot be explained by thermal expansion and is consistent with predictions from ab‐initio calculations based upon the generation of vacancy‐interstitial pairs of zirconium and oxygen.
A simple synthesis of the refractory ceramic sulfide CeS by electron beam irradiationPanetta, Riccardo; Latini, Alessandro
doi: 10.1111/jace.15070pmid: N/A
A new, relatively fast and simple synthesis of the refractory sulfide CeS using electron beam irradiation has been developed. Differently from the most common procedures involving highly reactive and/or toxic precursors such as cerium hydride and carbon disulfide, the approach here presented is based on the electron beam irradiation of pellets composed of a mixture of cerium sesquisulfide, cerium dioxide and graphite powders, i.e., nontoxic and nonreactive materials in ambient conditions that do not need any special caution during their use. CeS with a purity ≥98 wt% has been obtained, being Ce2O2S the impurity and whose amount can be lowered by annealing on a graphite surface.
A simple approach to manufacture ceramic coils based on liquid rope coiling effectXing, Chen; Yi, Meiyu; Wang, Guowei; Wang, Xin; Guo, Fangwei; Zhao, Xiaofeng; Xiao, Ping
doi: 10.1111/jace.15076pmid: N/A
A micrometer scale method based on the principle of liquid rope coiling with the assistance of nonsolvent‐induced phase inversion is introduced to fabricate YSZ coils. The YSZ coils with the filament diameter of several hundreds of micrometer exhibit stable spring properties and excellent elongation at failure. With the spring rate in the range from ~2 N/mm to ~21 N/mm and the elongation up to 4.36%, both the two properties can be effectively controlled and tailored since they both strongly depend on the geometric dimensions varied with the process parameters. Besides, the simple method provides an alternative method for the large‐scale production and customization of ceramic coils with diverse applications.
Development of a novel proton conducting fuel cell based on a Ni‐YSZ supportHanifi, Amir R.; Sandhu, Navjot K.; Etsell, Thomas H.; Sarkar, Partha
doi: 10.1111/jace.15084pmid: N/A
A new proton conducting fuel cell design based on the BZCYYb electrolyte is studied in this research. In high‐performance YSZ‐based SOFCs, the Ni‐YSZ support plays a key role in providing required electrical properties and robust mechanical behavior. In this study, this well‐established Ni‐YSZ support is used to maintain the proton conducting fuel cell integrity. The cell is in a Ni‐YSZ (375 μm support)/Ni‐BZCYYb (20 μm anode functional layer)/BZCYYb (10 μm electrolyte)/LSCF‐BZCYYb (25 μm cathode) configuration. Maximum power density values of 166, 218, and 285 mW/cm2 have been obtained at 600°C, 650°C, and 700°C, respectively. AC impedance spectroscopy results show values of 2.17, 1.23, and 0.76 Ω·cm2 at these temperatures where the main resistance contributor above 600°C is ohmic resistance. Very fine NiO and YSZ powders were used to achieve a suitable sintering shrinkage which can enhance the electrolyte sintering. During cosintering of the support and BZCYYb electrolyte layers, the higher shrinkage of the support layer led to compressive stress in the electrolyte, thereby enhancing its densification. The promising results of the current study show that a new generation of proton conducting fuel cells based on the chemically and mechanically robust Ni‐YSZ support can be developed which can improve long‐term performance and reduce fabrication costs of proton conducting fuel cells.
Fabrication of highly homogeneous Al‐doped TiO2 nanotubes by nanolamination of atomic layer depositionSu, Chung‐Yi; Wang, Chih‐Chieh; Hsueh, Yang‐Chih; Gurylev, Vitaly; Kei, Chi‐Chung; Perng, Tsong‐Pyng
doi: 10.1111/jace.15044pmid: N/A
Conformal parallel arrays of Al‐doped TiO2 nanotubes were fabricated by atomic layer deposition. TiO2/Al2O3 bilayered shells were grown on a polycarbonate template by various cyclic sequences of TiO2 and Al2O3. The doping level of Al could be tuned by the fraction of cycle number of Al2O3. From the depth profiles measured by second ion mass spectrometry, Al is uniformly distributed across the thickness, which is also supported by the analyses of X‐ray diffraction, X‐ray photoelectron spectroscopy, and Raman spectroscopy. A uniform bulk solubility of ~7 at.% and the surface concentration of ~18 at.% were observed with the cycle ratio of Al2O3: TiO2 at 0.04.
Splitting upconversion emission and phonon‐assisted population inversion of Ba2Y(BO3)2Cl:Yb3+, Er3+ phosphorHuang, Anjun; Yang, Zhengwen; Yu, Chengye; Qiu, Jianbei; Song, Zhiguo
doi: 10.1111/jace.15094pmid: N/A
Upconversion (UC) peak of 4S3/2→4I15/2 transition of Er3+ is close to that of 2H11/2→4I15/2 transition. The UC emission splitting of Er3+ caused by coordination fields of host results in that it is difficult to confirm which transitions (4S3/2→4I15/2 or 2H11/2→4I15/2) are responsible for the splitting UC emission peaks. In this work, the UC luminescence peaks located at 524, 540, 551, 565, 662, 677, and 683 nm were observed in the Ba2Y(BO3)2Cl:Yb3+, Er3+ phosphor upon the 980 nm excitation. The 524 and 540 nm UC emissions intensity were increased, while the 551 and 565 nm UC emissions intensity were decreased with the temperature increasing from 323 to 573 K, which is attributed to the phonon‐assisted population inversion from the 4S3/2 to 2H11/2 level. The temperature dependence of UC emission spectra demonstrated that the 524 and 540 nm UC emissions are from 2H11/2→4I15/2 transition, and 551 and 565 nm UC emissions are from the 4S3/2→4I15/2 transition. Temperature sensing property was characterized by the UC intensity ratio of the 2H11/2→4I15/2 transition to 4S3/2→4I15/2 transition. The Ba2Y(BO3)2Cl:Yb3+,Er3+ phosphor has potential application as the non‐contact temperature sensor.