Tensile Creep Behavior and Thermal Stability of Orthogonal Three-Dimensional Woven TyrannoTM ZMI Fiber/Silicon-Titanium-Carbon-Oxygen Matrix Composites

2004 ◽  
Vol 85 (2) ◽  
pp. 393-400 ◽  
Author(s):  
Toshio Ogasawara ◽  
Takashi Ishikawa ◽  
Yutaka Ohsawa ◽  
Yasuo Ochi ◽  
Shijie Zhu
2021 ◽  
Vol 15 (2) ◽  
pp. 164-169
Author(s):  
Jian Gu ◽  
Sea-Hoon Lee ◽  
Daejong Kim ◽  
Hee-Soo Lee ◽  
Jun-Seop Kim

Improvement of the thermal stability of continuous SiC fiber reinforced SiC ceramic matrix composites (SiCf/SiC CMC) by the pre-treatment of SiC fillers and the suppression of oxidation during polymer impregnation and pyrolysis (PIP) process were investigated. Dense SiCf/SiC CMCs were fabricated using the slurry infiltration and PIP process under a purified argon atmosphere. Structure and mechanical properties of the SiCf/SiC CMC heated at different temperatures were evaluated. The flexural strength of the SiCf/SiC CMC decreased only 15.3%after heating at 1400 ?C, which exhibited a clear improvement compared with the literature data (49.5% loss), where severe thermal deterioration of SiCf/SiC composite occurred at high temperatures by the crystallization and decomposition of the precursor-derived ceramic matrix. The thermal stability of the SiCf/SiC CMC fabricated by PIP process was improved by the pre-treatment of SiC fillers for removing oxides and the strict atmosphere control to prevent oxidation.


2002 ◽  
Vol 2002.1 (0) ◽  
pp. 355-356
Author(s):  
Toshio Ogasawara ◽  
Takashi Ishikawa ◽  
Shi jie Zhu ◽  
Yasuo Ochi ◽  
Yutaka Ohsawa

2015 ◽  
Vol 35 (4) ◽  
pp. 367-376 ◽  
Author(s):  
Nay Win Khun ◽  
Henry Kuo Feng Cheng ◽  
Lin Li ◽  
Erjia Liu

Abstract Polyamide 6 (PA6) matrix composites were prepared by incorporating multiwalled carbon nanotubes (MWCNTs) or by co-incorporating MWCNTs and carbon black (CB) of different contents. The thermal, mechanical and tribological properties of the composites were investigated using thermogravimetric analysis, nano-indentation, ball-on-disc micro-tribological test and micro-scratch test. It was found that a proper carbon filler content in the composites promoted the thermal stability of the composites, but an excessive loading of carbon fillers degraded the thermal stability of the composites. Although the hardness of the composites decreased with increased carbon filler content, the composites filled with mixed MWCNTs and CB had a higher load bearing capacity than the ones without CB. The tribological results indicated that the increased carbon filler content apparently lowered the friction coefficient of the composites due to the lubricating effect of the carbon fillers. It was also observed that the friction coefficients of the PA6-MWCNT-CB composites were consistently higher than those of the PA6-MWCNT composites due to the lower wear resistance of the PA6-MWCNT-CB composites. The scratch resistance of the composites decreased with increased carbon filler content due to the reduced cohesive strength of the composites.


2015 ◽  
Vol 70 (4) ◽  
pp. 215-219 ◽  
Author(s):  
Wei Li ◽  
Chang-Hong Li ◽  
Ying-Qun Yang ◽  
Heng-Feng Li

AbstractA new copper(II) coordination polymer [Cu2(C5H4NCOO)2(C7H5N4)2]n (1) has been synthesized with 4-pyridinecarboxylate and 3-(pyridin-2-yl)-1,2,4-triazolyl ligands. The crystal structure shows that two neighboring copper(II) ions are coordinated with two deprotonated (anionic) 3-(pyridin-2-yl)-1,2,4-triazole ligands to form a binuclear structure. Adjacent binuclear units are linked by 4-pyridinecarboxylate anions to form a three-dimensional network structure. The magnetic, fluorescent, and electrochemical properties and thermal stability of 1 were studied. The results show that 1 exhibits antiferromagnetic interaction, and upon excitation at 318 nm, it has an intense fluorescent emission at approximately 430 nm. The electron transfer of 1 is irreversible in electrode reactions. The thermogravimetric analysis shows that 1 is stable below 240 °C.


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