Effect of Crack Length on Strength Recovery of Silicon-Carbide-Whisker-Reinforced Silicon Nitride Upon Healing Treatment

2019 ◽  
Vol 11 (12) ◽  
pp. 1723-1730 ◽  
Author(s):  
Jun Feng Hu ◽  
Xi Deng ◽  
Yong Yang ◽  
Zhou Chen
Keyword(s):  
Heat Treatment ◽  
Silicon Carbide ◽  
Silicon Nitride ◽  
Heating Temperature ◽  
Complete Healing ◽  
Treatment Temperature ◽  
Aluminosilicate Glass ◽  
Crack Healing ◽  
Silicon Carbide Whisker ◽  
Strength Recovery

A silicon carbide whisker (SiCw) reinforced silicon nitride (Si3N4) composite ceramic was selected to study the crack-healing performance. Pre-cracks of various length were introduced on the tensile side of specimens by Vickers hardness tester. The crack-healing performance as a function of heating temperature and crack dimension, as well as the crack-healing mechanism were investigated. The optimal heat treatment temperature for crack-healing of Si3N4/SiCw is 1200–1300 °C. The treatment allows complete healing of a crack of 200 μm after heat treated at 1300 °C, and achievement of a substantial strength recovery for pre-cracked specimens even with much longer cracks (1200 μm). Crack closure and strength recovery of the pre-cracked specimen were considered to be triggered by the creation of SiO2, liquid aluminosilicate glass and silicon yttrium oxide by the oxidation reaction as filling mechanism during heat treatment.

Analysis Of Oxygen Distribution In Interfaces In SiC Whisker Reinforced Si3 N4-Based Composites.

1991 ◽  
Vol 238 ◽  
Author(s):  
K. Das Chowdihury ◽  
R. W. Carpenter ◽  
W. Braue
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
High Resolution ◽  
Grain Boundary ◽  
Oxygen Distribution ◽  
Interfacial Layers ◽  
Silicon Carbide Whisker ◽  
Resolution Electron ◽  
Analytical Microscopy ◽  
Electron Imaging

ABSTRACTDiscontinuous and continuous interfacial layers at the whisker/matrix and grain boundary interfaces in silicon carbide whisker reinforced silicon nitride based composites were investigated by high resolution electron imaging and analytical microscopy. Wide differences in chemical and structural widths of the interfaces were observed.

1303 Crack-healing behavior of silicon nitride/silicon carbide composite at low oxygen partial pressure

2008 ◽  
Vol 2008.6 (0) ◽  
pp. 343-344
Author(s):  
Young-Soon JUNG ◽  
Wataru NAKAO ◽  
Koji TAKAHASHI ◽  
Kotoji ANDO ◽  
Sinji SAITO
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Crack Healing ◽  
Low Oxygen ◽  
Carbide Composite

scholarly journals The Influence of a Thermal Treatment on the Decay Resistance of Wood via FTIR Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Rui Du ◽  
Yamei Wang ◽  
Zhangjing Chen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heating Temperature ◽  
Initial Moisture Content ◽  
Cellulose Hydrolysis ◽  
Decay Resistance ◽  
Treatment Temperature ◽  
Ftir Analysis ◽  
Average Mass ◽  
Stretching Vibration ◽  
Vibration Wave

The decay resistance of wood can be improved via a vacuum heat treatment. The amount of nutrients from cellulose, hemicellulose, and lignin and amount of sugars needed by the fungi during their growth were investigated. The results showed that the absorbance peaks corresponding to absorbed CH3-CH2-, C=O, and the benzene ring skeleton stretching vibration all noticeably weakened with increased heat treatment. This indicated that the cellulose, hemicellulose, and lignin degraded to varying degrees. The specimens with a higher initial moisture content (MC) showed greater amounts of nutrient degradation after 2 h at the same heat treatment temperature. The chemical analysis results were in good agreement with the Fourier transform infrared (FTIR) analysis results. The decay resistance tests showed that the average mass loss of the heat-treated specimens was up to 10.8%, in contrast to 22.23% for the untreated specimens. Furthermore, the FTIR analysis of the heat and decay-resistance test showed that the vibration wave peaks that corresponded to CH3-CH2- at 2954 cm−1 showed noticeably less separation at higher heating temperature. This demonstrated that the cellulose hydrolysis in the wood decreased at higher heating temperatures, which explained why the decay resistance increased with increased heat treatment.

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