Nano β-SiAlON Powder Synthesized by Carbothermal Reduction and Nitridation of Ultrafine Al2O3-SiO2 Mixture Employing Sol-Gel Techniques

2003 ◽  
Vol 237 ◽  
pp. 117-122 ◽  
Author(s):  
Q. Li ◽  
C. Zhang ◽  
Katsutoshi Komeya ◽  
Junichi Tatami ◽  
Takeshi Meguro ◽  
...  
2007 ◽  
Vol 336-338 ◽  
pp. 927-929 ◽  
Author(s):  
Hai Jun Zhang ◽  
Hai Tang Zhang ◽  
Jin Qi Miao ◽  
Zi Liang Wang ◽  
Quan Li Jia ◽  
...  

Ultrafine β-sialon powder is synthesized by citrate sol-gel and carbothermal reduction and nitridation (CRN) process. The presence of small amounts of β-sialon as crystal seed can obviously accelerate the formation of final β-sialon product and lower its formation temperature. The effects of nitriding temperature on the formation of the final β-sialon are investigated. The mean particle size of the prepared β-sialon powder is 100 ~ 150 nm. The β-sialon precursor gel and the ultrafine β-sialon powder are characterized by XRD, TG-DTA and SEM. The isoelectric point of ultrafine β-sialon is pH 2.46.


Author(s):  
Hai Jun Zhang ◽  
H.T. Zhang ◽  
J.Q. Miao ◽  
Z.L. Wang ◽  
Quan Li Jia ◽  
...  

2012 ◽  
Vol 95 (6) ◽  
pp. 1871-1877 ◽  
Author(s):  
Juntong Huang ◽  
Heping Zhou ◽  
Zhaohui Huang ◽  
Guanghua Liu ◽  
Minghao Fang ◽  
...  

2004 ◽  
Vol 24 (10-11) ◽  
pp. 3251-3259 ◽  
Author(s):  
Jun-Min Qian ◽  
Ji-Ping Wang ◽  
Guan-Jun Qiao ◽  
Zhi-Hao Jin

2018 ◽  
Vol 281 ◽  
pp. 34-39
Author(s):  
Fa Liang Li ◽  
Fang Fu ◽  
Li Lin Lu ◽  
Hai Jun Zhang ◽  
Shao Wei Zhang

Ultrafine powders of β-Sialon were prepared by the combined sol-gel and microwave carbothermal reduction nitridation method, and their oxidation process was studied by a non-isothermal thermogravimetry method. The results indicated that two different mechanism functions respectively corresponded to the initial and final oxidation stages. The reverse Jander equation with activation energy of 240.5 kJ/mol and the Avrami-Erofeev equation with activation energy of 410.7 kJ/mol were respectively identified as the most probable mechanism function for the initial and final oxidation stages in the temperature range of 1423-1623 K.


2010 ◽  
Vol 152-153 ◽  
pp. 1683-1686
Author(s):  
Qing Wang ◽  
Ya Hui Zhang

Biomorphic silicon carbide (bioSiC) was prepared by high temperature pyrolysis and sol-gel and carbothermal reduction processing at 1600 oC. The morphology and microstructure of carbon-silica composites and purified bioSiC samples were characterized by scanning electron microscopy. The phase composition of the resulting sample was analyzed by X-ray diffraction. The results suggest that the bioSiC mainly consists of cubic ß-SiC, and principally replicates the shape and microstructure of the carbon template.


2008 ◽  
Vol 1094 ◽  
Author(s):  
Kwok Cheung Li ◽  
Dickon H. L. Ng

AbstractWe have successfully produced biomorphic SiC ceramics from silica-infiltrated wood samples of balsa (Ochroma pyramidale) and flame tree (Delonix regia). This conversion of wood sample to a structure of SiC was performed by a sol-gel technique and a carbothermal reduction process. The biomorphic products were confirmed containing β-SiC and their structures were replica of the original structures of the raw wood samples. The biomorphic products from the denser flame tree (C-SiC) had higher specific strength than that from the biomorphic product from balsa (SiC).


1998 ◽  
Vol 13 (9) ◽  
pp. 2533-2538 ◽  
Author(s):  
G. W. Meng ◽  
L. D. Zhang ◽  
C. M. Mo ◽  
S. Y. Zhang ◽  
Y. Qin ◽  
...  

Preparation of β–SiC nanorods with and without amorphous SiO2 wrapping layers was achieved by carbothermal reduction of sol-gel derived silica xerogels containing carbon nanoparticles. The β–SiC nanorods with amorphous SiO2 wrapping layers were obtained by carboreduction at 1650 °C for 1.5 h, and at the end of 1.5 h the temperature was steeply raised to 1800 °C and held for 30 min; they are typically up to 20 µm in length. The diameters of the center thinner β–SiC nanorods within the amorphous SiO2 wrapping layers are in the range 10–30 nm, while the outer diameters of the corresponding amorphous SiO2 wrapping layers are between 20 and 70 nm. The β–SiC nanorods without amorphous SiO2 wrapping layers were produced by carbothermal reduction only at 1650 °C for 2.5 h, and their diameters are in agreement with those of the center thinner β–SiC nanorods wrapped in amorphous SiO2 layers. Large quantities of SiC rod nuclei and the nanometer-sized nucleus sites on carbon nanoparticles are both favorable to the formation of much thinner β–SiC nanorods. The formation of the outer amorphous SiO2 wrapping layer is from the combination reaction of decomposed SiO vapor and O2.


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