Preparation and Characterization of SiC Fibers from PCS by Electrospinning, Curing and Calcination Process**

2021 ◽  
Vol 6 (42) ◽  
pp. 11630-11637
Author(s):  
Shao‐Hwa Hu ◽  
Jiao‐Jiao Yuan ◽  
Li‐Chun Wu ◽  
Hang Dai ◽  
Ya‐Zhao Ai ◽  
...  
Author(s):  
G. Das ◽  
R. E. Omlor

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.


2021 ◽  
Vol 41 (9) ◽  
pp. 4697-4709
Author(s):  
R.T. Bhatt ◽  
F. Sola’ ◽  
L.J. Evans ◽  
R.B Rogers ◽  
D.F. Johnson
Keyword(s):  

2015 ◽  
Vol 1 ◽  
pp. 8 ◽  
Author(s):  
Juan Huguet-Garcia ◽  
Aurélien Jankowiak ◽  
Sandrine Miro ◽  
Renaud Podor ◽  
Estelle Meslin ◽  
...  

2008 ◽  
Vol 55-57 ◽  
pp. 369-372 ◽  
Author(s):  
T. Sreesattabud ◽  
Anucha Watcharapasorn ◽  
Sukanda Jiansirisomboon

Lead zirconate titanate/tungsten oxide (PZT/WO3) ceramics were prepared from the powders synthesized by a modified triol sol-gel processing method. In this study, the starting materials used for synthesis of PZT-sol were zirconium (IV) propoxide, titanium (IV) isopropxide, lead (II) acetate trihydrate and 1,1,1,- tris (hydroxymethyl) ethane. To prepare PZT/xWO3 powders (where x = 0, 0.5, 1 and 3 wt%), nano-sized WO3 was ultrasonically dispersed and mixed with the PZT sol, dried and calcined at 600°C for 4 h. X-ray diffraction results indicated that fully crystallized powders were obtained. Phase characterization suggested that at high WO3 concentration, the reaction between PZT and WO3 occurred during the calcination process. To prepare PZT/xWO3 ceramics, the powders were pressed and sintered at 1100°C for 6 h. Phase characterization by XRD indicated that the content of WO3 significantly affected tetragonal-to-rhombohedral phase transition. Microstructure of thermally etched samples showed that increasing the content of WO3 decreased grain size of the ceramics.


2012 ◽  
Vol 583 ◽  
pp. 86-90 ◽  
Author(s):  
Hai Bin Li ◽  
Xin Yong Li ◽  
Yan De Song ◽  
Shu Guang Chen ◽  
Ying Wang ◽  
...  

TiO2nanotubes were prepared via a hydrothermal route. CeO2nanoparticles with diameters around 5nm were loaded onto the surface of TiO2nanotubes via a deposition approach followed by a calcination process. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectroscopy (UV-vis) were applied for the characterization of the as-prepared CeO2/TiO2nanotubes composites. The results show that CeO2particles are highly dispersed on the surface of TiO2nanotubes. The TiO2 nanotubes are modified to response to the visible light due to the combination with CeO2. The CeO2/TiO2nanotubes composites with a CeO2/TiO2atomic ratio of 2.5% show a further improvement on the photocatalytic activity for degradation of Rhodamine B in water. The presence of CeO2improves the light absorption of TiO2nanotubes and inhibits the electron-hole recombination.


2020 ◽  
Vol 405 ◽  
pp. 324-329
Author(s):  
Erika Mudra ◽  
Ivan Shepa ◽  
Alexandra Kovalcikova ◽  
Ondrej Milkovič ◽  
Jan Dusza

SnO2 is an n-type semiconductor with the band gap energy of 3.6 eV. It has been widely studied for gas sensing applications, the sensitivity of which can be easily tuned by the operating temperature. The presented paper is focused on the preparation and detailed characterization of the hollow SnO2 nano/microfibers suitable for gas detection sensors. Ceramic SnO2 fibers were produced by needleless electrospinning and followed by the calcination process. The characterization was performed by SEM, TEM, XRD, and Raman spectroscopy. The precursor PVP/SnO2 fibers had amorphous nature. The calcination of the electro spun precursor resulted in the formation of hollow crystalline fibrous structures. The formation mechanism of hollow fibers has been described. Subsequently, a homogeneous fibrous layer was created by the spin coating method for gas sensing applications.


2020 ◽  
Vol 307 ◽  
pp. 339-344
Author(s):  
Ishak Qayyum Afiqah ◽  
Nik Aziz Nik Ali ◽  
Abd Majid Siti Nurhaziqah ◽  
Hasiah Salleh

Age of monstrous amount of underutilized marine processing byproducts has been perceived as waste and many effort were given to utilize these materials in various application. With an incredible number of study on these byproducts, some compound were identified and apply for human utilization. Hydroxyapatite (HAp) is the main inorganic calcium phosphate mineral with excellent osteoconductivity, good bioactivity and biocompatibility. The production of HAp powder from synthetic process involves many chemicals with complicated procedures. Due to this matter, the raw HAp powder was extracted from natural sources selayang fish bones. Extortion process started with boiling fish bones to eliminate adherent fish meats. After calcination process fish bone were dried in room temperature before crushed by using grinder to obtain the powder. Next, the powder undergo calcination process at 900°C for 5 hours. The characterization of raw HAp was done via X-ray Diffraction, Fourier Transform Infrared Spectometer, Scanning Electron Microscopy, and Thermogravimetric analysis.


1997 ◽  
Vol 3 (S2) ◽  
pp. 733-734
Author(s):  
Mani Gopal

Silicon carbide (SiC) composites are receiving much attention for structural use at high temperatures. One class of composites are those reinforced with SiC fibers. The SiC fibers are coated with boron nitride (BN) which is weakly bonded to the fiber. During fracture, the coating deflects cracks causing pull-out of the fibers (Fig. 1). This process of fiber pull-out consumes energy and increases the toughness of the composite. Although much work has been done on characterizing these materials by SEM, not much has been done using TEM due to difficulties in specimen preparation. The purpose of this study is to characterize these fibers and composites using conventional and analytical TEM.In this study, TEM specimens were prepared by dimpling and ion milling. Careful control of the preparation was needed to ensure the integrity of the SiC-BN interface. Figure 2a is a TEM image of the fiber showing delamination at the SiC-BN interface.


2016 ◽  
Vol 42 (13) ◽  
pp. 15107-15112 ◽  
Author(s):  
Qinggang Li ◽  
Zhi Wang ◽  
Xin Cheng ◽  
Haiming Wen

2011 ◽  
Vol 675-677 ◽  
pp. 1089-1092 ◽  
Author(s):  
Wen Pan ◽  
Ning Hui Wang ◽  
Guo Feng Li ◽  
Gui Ling Ning

A novel synthesis route for the production of Sr3MgSi2O8:Eu2+,Dy3+ sub-micron quasisphere phosphor powder is reported. Both the host and activator cations were co-precipitated in water-ethanol mixed solutions and precipitation was performed with analytical grade ammonium citratetribasic. As the dispersion media, optimum concentration for PEG in the precursor solution is determined to be 0.08 g/mL. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and fluorescence spectrophotometer were employed to characterize the phosphor. The effect of the calcining temperature on the crystalline particle and luminescence properties of Sr3MgSi2O8:Eu2+,Dy3+ is systematically discussed. Sr3MgSi2O8:Eu2+,Dy3+ single phased quasi-sphere phosphor was achieved by calcining the asprecipitated precursor at 1100°C. Sr2SiO4 was identified as the intermediate phase during the calcination process. Despite the small particle size, the emission intensities were higher by the present method. However, the afterglow characteristic was not better than that prepared by solidstate reaction in the comparable condition.


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