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Zhang D, Yu R, Feng X, Guo X, Yang Y, Xu X. Enhanced Mechanical Properties of Al 2O 3 Nanoceramics via Low Temperature Spark Plasma Sintering of Amorphous Powders. Materials (Basel) 2023; 16:5652. [PMID: 37629943 PMCID: PMC10456409 DOI: 10.3390/ma16165652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/08/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023]
Abstract
In this work, Al2O3 nanoceramics were prepared by spark plasma sintering of amorphous powders and polycrystalline powders with similar particle sizes. Effective comparisons of sintering processes and ultimate products depending on starting powder conditions were explored. To ensure near-full density higher than 98% of the Al2O3 nanoceramics, the threshold temperature in SPS is 1450 °C for polycrystalline Al2O3 powders and 1300 °C for amorphous powders. The low SPS temperature for amorphous powders is attributed to the metastable state with high free energy of amorphous powders. The Al2O3 nanoceramics prepared by amorphous powders display a mean grain size of 170 nm, and superior mechanical properties, including high bending strength of 870 MPa, Vickers hardness of 20.5 GPa and fracture toughness of 4.3 MPa∙m1/2. Furthermore, the Al2O3 nanoceramics prepared by amorphous powders showed a larger dynamic strength and dynamic strain. The toughening mechanism with predominant transgranular fracture is explained based on the separation of quasi-boundaries.
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Affiliation(s)
- Dongjiang Zhang
- Xi’an Modern Control Technology Research Institute, Xi’an 710065, China
| | - Rui Yu
- Xi’an Modern Control Technology Research Institute, Xi’an 710065, China
| | - Xuelei Feng
- Xi’an Modern Control Technology Research Institute, Xi’an 710065, China
| | - Xuncheng Guo
- Xi’an Modern Control Technology Research Institute, Xi’an 710065, China
| | - Yongkang Yang
- School of Materials Science & Engineering, Chang’an University, Xi’an 710061, China
| | - Xiqing Xu
- School of Materials Science & Engineering, Chang’an University, Xi’an 710061, China
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Arıbuğa D, Akkaşoğlu U, Çiçek B, Balcı-Çağıran Ö. Enhanced Sinterability, Thermal Conductivity and Dielectric Constant of Glass-Ceramics with PVA and BN Additions. Materials (Basel) 2022; 15:1685. [PMID: 35268916 DOI: 10.3390/ma15051685] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/11/2022] [Accepted: 02/13/2022] [Indexed: 02/04/2023]
Abstract
With the rapid development of the microelectronics industry, many efforts have been made to improve glass-ceramics' sinterability, thermal conductivity, and dielectric properties, which are essential components of electronic materials. In this study, low-alkali borosilicate glass-ceramics with PVA addition and glass-BN composites were prepared and successfully sintered at 770 °C. The phase composition, density, microstructure, thermal conductivity, and dielectric constant were investigated. It was shown that PVA addition contributes to the densification process of glass-ceramics (~88% relative density, with closed/open pores in the microstructure) and improves the thermal conductivity of glass material from 1.489 to 2.453 W/K.m. On the other hand, increasing BN addition improves microstructures by decreasing porosities and thus increasing relative densities. A glass-12 wt. % BN composite sample exhibited almost full densification after sintering and presented apparent and open pores of 2.6 and 0.08%, respectively. A high thermal conductivity value of 3.955 W/K.m and a low dielectric constant of 3.00 (at 5 MHz) were observed in this material. Overall, the resulting glass-ceramic samples showed dielectric constants in the range of 2.40-4.43, providing a potential candidate for various electronic applications.
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Hsu SLC, Chen YT, Chen ML, Chen IG. Low Sintering Temperature Nano-Silver Pastes with High Bonding Strength by Adding Silver 2-Ethylhexanoate. Materials (Basel) 2021; 14:ma14205941. [PMID: 34683538 PMCID: PMC8537409 DOI: 10.3390/ma14205941] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/05/2021] [Accepted: 10/05/2021] [Indexed: 11/16/2022]
Abstract
A silver precursor (silver 2-ethylhexanoate) and silver nanoparticles were synthesized and used to prepare a low sintering temperature nano-silver paste (PM03). We optimized the amount of silver 2-ethylhexanoate added and the sintering temperature to obtain the best performance of the nano-silver paste. The relationship between the microstructures and properties of the paste was studied. The addition of silver 2-ethylhexanoate resulted in less porosity, leading to lower resistivity and higher shear strength. Thermal compression of the paste PM03 at 250 °C with 10 MPa pressure for 30 min was found to be the proper condition for copper-to-copper bonding. The resistivity was (3.50 ± 0.02) × 10-7 Ω∙m, and the shear strength was 57.48 MPa.
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Holliman PJ, Connell A, Jones EW, Kershaw CP. Metal Oxide Oxidation Catalysts as Scaffolds for Perovskite Solar Cells. Materials (Basel) 2020; 13:ma13040949. [PMID: 32093276 PMCID: PMC7079644 DOI: 10.3390/ma13040949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/15/2020] [Accepted: 02/18/2020] [Indexed: 11/23/2022]
Abstract
Whilst the highest power conversion efficiency (PCE) perovskite solar cell (PSC) devices that have reported to date have been fabricated by high temperature sintering (>500 °C) of mesoporous metal oxide scaffolds, lower temperature processing is desirable for increasing the range of substrates available and also decrease the energy requirements during device manufacture. In this work, titanium dioxide (TiO2) mesoporous scaffolds have been compared with metal oxide oxidation catalysts: cerium dioxide (CeO2) and manganese dioxide (MnO2). For MnO2, to the best of our knowledge, this is the first time a low energy band gap metal oxide has been used as a scaffold in the PSC devices. Thermal gravimetric analysis (TGA) shows that organic binder removal is completed at temperatures of 350 °C and 275 °C for CeO2 and MnO2, respectively. By comparison, the binder removal from TiO2 pastes requires temperatures >500 °C. CH3NH3PbBr3 PSC devices that were fabricated while using MnO2 pastes sintered at 550 °C show slightly improved PCE (η = 3.9%) versus mesoporous TiO2 devices (η = 3.8%) as a result of increased open circuit voltage (Voc). However, the resultant PSC devices showed no efficiency despite apparently complete binder removal during lower temperature (325 °C) sintering using CeO2 or MnO2 pastes.
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Guo J, Legum B, Anasori B, Wang K, Lelyukh P, Gogotsi Y, Randall CA. Cold Sintered Ceramic Nanocomposites of 2D MXene and Zinc Oxide. Adv Mater 2018; 30:e1801846. [PMID: 29944178 DOI: 10.1002/adma.201801846] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/11/2018] [Indexed: 06/08/2023]
Abstract
Nanocomposites containing 2D materials have attracted much attention due to their potential for enhancing electrical, magnetic, optical, mechanical, and thermal properties. However, it has been a challenge to integrate 2D materials into ceramic matrices due to interdiffusion and chemical reactions at high temperatures. A recently reported sintering technique, the cold sintering process (CSP), which densifies ceramics with the assistance of transient aqueous solutions, provides a means to circumvent the aforementioned problems. The efficacious co-sintering of Ti3 C2 Tx (MXene), a 2D transition carbide, with ZnO, an oxide matrix, is reported. Using CSP, the ZnO-Ti3 C2 Tx nanocomposites can be sintered to 92-98% of the theoretical density at 300 °C, while avoiding oxidation or interdiffusion and showing homogeneous distribution of the 2D materials along the ZnO grain boundaries. The electrical conductivity is improved by 1-2 orders of magnitude due to the addition of up to 5 wt% MXene. The hardness and elastic modulus show an increase of 40-50% with 0.5 wt% MXene, and over 150% with 5 wt% of MXene. The successful densification of ZnO-MXene nanocomposite demonstrates that the cold sintering of ceramics with 2D materials is a promising processing route for designing new nanocomposites with a diverse range of applications.
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Affiliation(s)
- Jing Guo
- Materials Research Institute and Department of Materials Science & Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Benjamin Legum
- Department of Materials Science and Engineering and A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA, 19104, USA
| | - Babak Anasori
- Department of Materials Science and Engineering and A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA, 19104, USA
| | - Ke Wang
- Materials Research Institute and Department of Materials Science & Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Pavel Lelyukh
- Department of Materials Science and Engineering and A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA, 19104, USA
| | - Yury Gogotsi
- Department of Materials Science and Engineering and A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia, PA, 19104, USA
| | - Clive A Randall
- Materials Research Institute and Department of Materials Science & Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
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