scholarly journals Decreasing Resistivity of Silicon Carbide Ceramics by Incorporation of Graphene

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3586
Author(s):  
Ningning Cai ◽  
Daidong Guo ◽  
Guoping Wu ◽  
Fangmin Xie ◽  
Shouhong Tan ◽  
...  

Silicon carbide (SiC) ceramic is an ideal material for mechanical seal because of its super hardness, high strength, low friction coefficient, good thermal conductivity, and resistance to friction and wear. However, due to relatively high resistivity of SiC ceramic, the triboelectric charge caused by rubbing of mechanical seal end-faces could not be released. It is terrible that the accumulation of triboelectric charge could cause electrochemical corrosion, which would accelerate wear. To decrease the resistivity of SiC ceramic is a desire for improving the performance of mechanical seal. In this research, decreasing resistivity of pressureless sintered SiC ceramic was investigated by conductive pathways through semiconductive grains in a body by incorporation of graphene, which has an extremely low resistivity. With the increasing of graphene from 0 to 2 wt.%, the volume resistivity of SiC ceramics sintered with graphene decreased logarithmically from >106 to around 200 Ω·cm, and the bulk density decreased gradually, from 3.132 to 3.039 g/cm3. In order to meet the requirements of mechanical seal, SiC ceramic sintered with 1 wt.% of graphene, for which the volume resistivity is of 397 Ω·cm, the bulk density is of 3.076 g/cm3, and the flexural strength is of 364 MPa, was optimized when all properties were taken into consideration. It is possible to fabricate low-resistivity SiC ceramic as a useful friction pair material for mechanical seal in a special condition, without excessive loss of their excellent mechanical properties by the introduction of partially connected graphene as conductive pathway into semiconducting ceramic.

2014 ◽  
Vol 1027 ◽  
pp. 146-149
Author(s):  
Min Hui Liu ◽  
Fei Hu Zhang ◽  
Guo Dong Lu

Silicon carbide ceramics with its excellent physical and mechanical properties have become the preferred material for space large diameter mirror. Diamond wheel grinding is the main way of SiC ceramics forming processing. Subsurface cracks is generated due to the high hardness and brittleness of the material after grinding. In order to remove the impact of cracks, poishing processing with very low efficiency is applied, so it is significant to control the depth of silicon carbide ceramic grinding subsurface cracks and shorten the processing cycle.In this paper grinding experiment of SiC ceramic is conducted. The method of cross-section polishing combined with scanning electron microscope observation is used to research grinding subsurface cracks. The depth of broken surface layer and the maximum depth of sub-surface cracks were proposed to evaluate the grinding subsurface cracks. The result show broken surface layer depth and the maximum depth of sub-surface cracks increase with the decreasement of spindle speed, and increasement of feed rate and grinding depth.


2014 ◽  
Vol 34 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Mathias Herrmann ◽  
Kerstin Sempf ◽  
Michael Schneider ◽  
Uwe Sydow ◽  
Kerstin Kremmer ◽  
...  

2009 ◽  
Vol 61 (8) ◽  
pp. 657-664 ◽  
Author(s):  
U. Sydow ◽  
M. Schneider ◽  
M. Herrmann ◽  
H.-J. Kleebe ◽  
A. Michaelis

2014 ◽  
Vol 34 (7) ◽  
pp. 1687-1693 ◽  
Author(s):  
M. Herrmann ◽  
K. Sempf ◽  
H. Wendrock ◽  
M. Schneider ◽  
K. Kremmer ◽  
...  

2015 ◽  
Vol 41 (3) ◽  
pp. 4422-4429 ◽  
Author(s):  
M Herrmann ◽  
K Sempf ◽  
K Kremmer ◽  
M Schneider ◽  
A Michaelis

2012 ◽  
Vol 562-564 ◽  
pp. 27-30
Author(s):  
Zhu Xing Tang ◽  
Hui Hui Tan ◽  
He Zhang ◽  
Ke Zhou Xu ◽  
Ying Zhang

The Si¬2ON2-SiC ceramic was fabricated by pressureless sintering method. In this paper we researched the effect of SiC content (50%, 70% and 90%) on the performance of silicon oxynitride bonded silicon carbide ceramics. Through testing and analyzing the SEM, XRD, density and porosity of the final silicon oxynitride bonded silicon carbide ceramic samples, the results show that: changes in SiC content not only affect the bulk density of the composites but also affect the phase composition and the microstructure of fracture surface. The most compactness experimental product is sintered at1500°C containing 50wt% SiC.


2010 ◽  
Vol 434-435 ◽  
pp. 162-164
Author(s):  
Dong Lin Zhao ◽  
Lei Zhang ◽  
Zeng Min Shen

Nano silicon carbide ceramics were prepared via precursor pyrolysis. Polycarbosilane (PCS) and divinylbenzene (DVB) were selected as a precursor to silicon carbide ceramics and a cross-linking reagent for PCS, respectively. The cross-linking properties and pyrolysis of PCS and DVB were investigated by changing the mass ratios of PCS/DVB. The mass ratio of PCS/DVB has a great effect on silicon carbide ceramic yield. The cured PCS/DVB with a mass ratio of 1:0.5 has the highest SiC ceramic yield (63.1%) at the temperature up to 1500 °C and its pyrolyzates consiste of nano silicon carbide with a diameter of 10-40 nm. The microstructures of the nano silicon carbide ceramics were characterized by SEM and XRD. The pyrolysis behavior of the cured PCS/DVB was characterized by thermogravimetry in nitrogen atmosphere.


2011 ◽  
Vol 64 (3) ◽  
pp. 218-224 ◽  
Author(s):  
U. Sydow ◽  
K. Sempf ◽  
M. Herrmann ◽  
M. Schneider ◽  
H.-J. Kleebe ◽  
...  

2012 ◽  
Vol 27 (9) ◽  
pp. 965-969
Author(s):  
Xiao YANG ◽  
Xue-Jian LIU ◽  
Zheng-Ren HUANG ◽  
Gui-Ling LIU ◽  
Xiu-Min YAO

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