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Materials 2019, 12(7), 1181; https://doi.org/10.3390/ma12071181

Effect of Urchin-Like Mullite Whiskers on the High-Temperature Performance of Porous SiO2-Based Ceramic Molds

1,†, 1,2,*,†, 1, 1, 1,* and 1
1
State Key Laboratory of Manufacturing Systems Engineering, School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
2
Collaborative Innovation Center for Advanced Aero-Engine, XueYuan Road No.37, HaiDian District, Beijing 100191, China
*
Authors to whom correspondence should be addressed.
The two authors contributed equally to this work.
Received: 12 March 2019 / Revised: 5 April 2019 / Accepted: 9 April 2019 / Published: 11 April 2019
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Abstract

Urchin-like mullite whiskers synthesized by the vapor–liquid–solid growth method were used to improve the high-temperature performance of porous gelcast SiO2-based ceramic molds. Aluminum was used to facilitate the synthesis of polycrystal urchin-like mullite whiskers which acted as bridges between particles. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to investigate the microstructures and phase compositions of the sintered ceramic samples, respectively. Urchin-like mullite whiskers with diameters of 0.2~1.0 µm and lengths of 1.0~8.0 µm were successfully synthesized in SiO2-based ceramic. When 15 vol% Al was added, the high-temperature strength at 1200 °C was improved from 8.5 to 27.5 MPa, and the creep deformation was decreased to 0.56 mm. Meanwhile, a sintering shrinkage below 0.3% was obtained, and the de-coring rate was accelerated by 67% compared to that of the pure SiO2-based ceramic. This method showed excellent high-temperature strength and high precision, having remarkable potential in the fabrication of hollow turbine blades. View Full-Text
Keywords: urchin-like mullite whiskers; high-temperature strength; SiO2 ceramic; Al additive; gelcasting urchin-like mullite whiskers; high-temperature strength; SiO2 ceramic; Al additive; gelcasting
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
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Chen, Y.; Lu, Z.; Wan, W.; Li, J.; Miao, K.; Li, D. Effect of Urchin-Like Mullite Whiskers on the High-Temperature Performance of Porous SiO2-Based Ceramic Molds. Materials 2019, 12, 1181.

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