Synthesis of Si3N4 from Na2SiF6 as a Solid Precursor: Microstructural Evolution

2007 ◽  
Vol 560 ◽  
pp. 109-114
Author(s):  
Ana Lilia Leal-Cruz ◽  
Martin I. Pech-Canul
Keyword(s):  
Weight Loss ◽  
Substrate Temperature ◽  
Microstructural Evolution ◽  
Microstructure Evolution ◽  
Processing Time ◽  
Processing Parameters ◽  
Processing Temperature ◽  
Morphology Changes ◽  
Porous Substrates

The effect of processing parameters on the weight loss of the silicon solid precursor (Na2SiF6) and the deposition characteristics and morphology of Si3N4 formed onto SiCp/Si porous substrates by CVD has been investigated. The results show that the weight loss of Na2SiF6 is most significantly affected by the processing temperature, followed by the processing time and the type of nitrogen precursor. Formation of Si3N4 is mostly influenced by the substrate temperature, followed by the type of nitrogen precursor and processing time. An increase in processing time and temperature from 60 to 120 min and from 900 to 1300 oC, respectively, favors dissociation of Na2SiF6 and formation of Si3N4. Moreover, N2 enhances Na2SiF6 dissociation and hampers Si3N4 formation, while the N2-NH3 mixture hinders the solid precursor dissociation and favors Si3N4 formation. With regard to microstructure evolution, it is found that in N2 the amount of Si3N4 increases with temperature and the morphology changes from wool-like and light fibers to thicker and compact fibers. When N2-NH3 is used and the processing temperature is increased, the morphology of Si3N4 is modified from deposits with wool-like and compact appearance to whiskers and spheres and finally to thick and compact fibers.

scholarly journals Optimization of Blending Parameters and Fiber Size of Kenaf-Bast-Fiber-Reinforced the Thermoplastic Polyurethane Composites by Taguchi Method

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Y. A. El-Shekeil ◽  
S. M. Sapuan ◽  
M. D. Azaman ◽  
M. Jawaid
Keyword(s):  
Processing Time ◽  
Thermoplastic Polyurethane ◽  
Processing Parameters ◽  
Compression Molding ◽  
Processing Temperature ◽  
Blending Method ◽  
Fiber Size ◽  
C 50 ◽  
Kenaf Fibers ◽  
Polyurethane Composites

“Kenaf-fibers- (KF-)” reinforced “thermoplastic polyurethane (TPU)” composites were prepared by the melt-blending method followed by compression molding. Composite specimens were cut from the sheets that were prepared by compression molding. The criteria of optimization were testing the specimens by tensile test and comparing the ultimate tensile strength. The aim of this study is to optimize processing parameters (e.g., processing temperature, time, and speed) and fiber size using the Taguchi approach. These four parameters were investigated in three levels each. The L9 orthogonal array was used based on the number of parameters and levels that has been selected. Furthermore, analysis of variance (ANOVA) was used to determine the significance of different parameters. The results showed that the optimum values were 180°C, 50 rpm, 13 min, and 125–300 micron for processing temperature, processing speed, processing time, and fiber size, respectively. Using ANOVA, processing temperature showed the highest significance value followed by fiber size. Processing time and speed did not show any significance on the optimization of TPU/KF.

scholarly journals Optimization of Processing Parameters and Fiber Content of Cocoa Pod Husk Fiber-Reinforced Thermoplastic Polyurethane Composites by Taguchi Method

2014 ◽  
Vol 564 ◽  
pp. 394-399 ◽  
Author(s):  
Y.A. El-Shekeil ◽  
S.M. Sapuan ◽  
M. Haron
Keyword(s):  
Processing Time ◽  
Thermoplastic Polyurethane ◽  
Processing Parameters ◽  
Fiber Content ◽  
Processing Temperature ◽  
Fiber Reinforced ◽  
Compression Moulding ◽  
Blending Method ◽  
Cocoa Pod Husk ◽  
Polyurethane Composites

A composite of cocoa (Theobroma cacao) pod husk (CPH) fiber reinforced themoplastic polyurethane (TPU) was prepared by melt-blending method followed by compression moulding. Specimens were cut from the sheets that were prepared by compression moulding. The criteria of optimization was testing the specimens by tensile test and comparing the ultimate tensile strength. The aim of this study is to optimize processing parameters and fiber loading using Taguchi approach. These four parameters were investigated in three levels each. The L9 orthogonal array was used based on the number of parameters and levels that have been selected. Furthermore ANOVA was used to determine the significance of parameters. The processing parameters chosen for this study were temperature, speed and time of processing and fiber content. The results showed that optimum values were 190°C, 40 rpm, 11min and 30% for processing temperature, processing speed, processing time and fiber content; respectively. Using ANOVA; fiber content showed the highest significance value followed by processing time. Processing temperature and speed showed no significance in the optimization of TPU/CPH.

Investigation and analysis of glass fabric/PVC composite laminates processing parameters

2018 ◽  
Vol 25 (3) ◽  
pp. 529-540 ◽  
Author(s):  
Vahid Zal ◽  
Hassan Moslemi Naeini ◽  
Ahmad Reza Bahramian ◽  
Amir Hossein Behravesh ◽  
Behnam Abbaszadeh
Keyword(s):  
Flexural Strength ◽  
Composite Laminates ◽  
Processing Time ◽  
Processing Parameters ◽  
Test Method ◽  
Bending Test ◽  
Maximum Effect ◽  
Processing Temperature ◽  
Matrix Degradation ◽  
The Matrix

Abstract In this work, the effects of processing parameters including temperature, time, and pressure on the properties of amorphous polyvinyl chloride (PVC)/fiberglass thermoplastic composite laminates were evaluated. The film stacking and hot pressing procedure was used to produce the composite laminates, and samples with [0/90]10 layup and thickness of 3 mm were produced. Flexural strength and modulus of the samples were measured using three-point bending test (according to ASTM D790 standard test method), and microscopic images were used to evaluate the failure mechanisms and impregnation quality. The effects of the parameters on the strength were studied using analysis of variance (ANOVA), and it was found that processing temperature has the maximum effect on the products strength and increase of the temperature up to 230°C increases the flexural strength while more increase of temperature results in the matrix degradation and strength reduction. Also, processing time improves the wetting and impregnation quality; however, more increase of the processing time results in the matrix degradation and excessive reduction of the strength.

Microstructural Evolution in Compositionally Tailored MoSi2/SiC Composites

1993 ◽  
Vol 322 ◽  
Author(s):  
S.E. Riddle ◽  
S. Jayashankar ◽  
M.J. Kaufman
Keyword(s):  
Mechanical Alloying ◽  
Microstructural Evolution ◽  
Processing Parameters ◽  
Processing Temperature ◽  
Processing Scheme ◽  
Powder Composition ◽  
Important Processing ◽  
Novel Processing ◽  
Sic Composites ◽  
Carbide Content

AbstractCompositionally tailored MoSi2/SiC composites with silicon carbide content ranging from 0 to 60 volume percent were synthesized through a novel processing scheme involving the mechanical alloying of elemental molybdenum, silicon, and carbon. The effects of important processing parameters such as the nominal powder composition and the processing temperature on the microstructural evolution during mechanical alloying and subsequent heating are described based on the results obtained from DTA and XRD.

scholarly journals The Energy-Efficient Processing of Fine Materials by the Micropyretic Synthesis Route

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
H. P. Li
Keyword(s):  
Energy Efficient ◽  
Processing Time ◽  
Combustion Temperature ◽  
Processing Parameters ◽  
The Novel ◽  
Diffusion Controlled ◽  
Efficient Processing ◽  
The One ◽  
Processing Techniques ◽  
Diffusion Controlled Reaction

Energy-efficient processing of TiB compound with nanowhiskers by micropyretic synthesis is investigated in this paper. Micropyretic synthesis not only offers shorter processing time but also excludes the requirement for high-temperature sintering and it is considered as the one of the novel energy-saving processing techniques. Experimental study and numerical simulation are both carried out to investigate the correlation of the processing parameters on the microstructures of the micropyretically synthesized products. The diffusion-controlled reaction mechanism is proposed in this study. It is noted that nanosize TiB whiskers only occurred when the combustion temperature is lower than the melting point of TiB but higher than the extinguished temperature. The results generated in the numerical calculation can be used as a helpful reference to select the proper route of processing nanosize materials. The Arrhenius-type plot of size and temperature is used to calculate the activation energy of TiB reaction. In addition to verifying the accuracy of the experimental measures, the reaction temperature for producing the micropyretically synthesized products with nanofeatures can be predicted.

Microstructure evolution and plastic deformation of Ni47Co53 alloy under tension

CrystEngComm ◽  
2022 ◽  
Author(s):  
ruibo ma ◽  
Lili Zhou ◽  
Yong-Chao Liang ◽  
Ze-an Tian ◽  
Yun-Fei Mo ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Rapid Solidification ◽  
Microstructural Evolution ◽  
Microstructure Evolution ◽  
Cooling Rates ◽  
Solidification Processes ◽  
Molecular Dynamics Methods

To investigate microstructural evolution and plastic deformation under tension conditions, the rapid solidification processes of Ni47Co53 alloy are first simulated by molecular dynamics methods at cooling rates of 1011, 1012...

Low frequency vibratory cleaning of paint and rust contaminants from machines parts

2021 ◽  
pp. 095440542110314
Author(s):  
Dieudonne Essola ◽  
Achille Pandong Njomoue ◽  
Florence Offole ◽  
Cyrille Adiang Mezoue ◽  
Crick Nelson Zanga ◽  
...  
Keyword(s):  
Processing Time ◽  
Low Frequency ◽  
Processing Parameters ◽  
Vibration Machine ◽  
Optimal Processing ◽  
Low Frequency Oscillations ◽  
Experimental Parameters ◽  
Process Fluid ◽  
Full Factorial ◽  
Fluid Parameters

This work investigates the effect of low frequency vibratory processing for cleaning and washing various machine components parts from rusts and old paints deposits. The experimental investigation was carried out with special prepared samples that were weighted and exposed to paints and rust contaminants. These samples were treated in universal horizontal vibration machine UVHM 4 × 10 with different combination of instrumental processing medium, process fluid, machine amplitude and frequency of oscillations. They were periodically reweighted after processing and compared to etalon with control of quantity of dust that have been removed, sample cleanliness and also other functional parameters. Statistical analysis has been used to characterize ongoing process and full factorial analysis to establish experimental parameters dependency. The result is showing the complex dependence of samples cleanliness to each processing parameters like processing time, amplitude of oscillations, frequency of oscillations, process fluid parameters, instrumental medium, etc. Between this parameters although the most important successively the amplitude of oscillations, the frequency of oscillations the processing medium and the processing fluid depending to his considered composition, the optimal processing time can be reach only by complex combination of all this parameters every of them carry an amplify coefficient. Low frequency oscillations can be used to monitor and optimize washing and cleaning operations of paints and rusts contaminations. That guarantees process automation, its effectiveness for a large industrial application.

PREDICTION OF PEEK RESIN PROPERTIES FOR PROCESSING MODELING USING MOLECULAR DYNAMICS

2021 ◽  
Author(s):  
KHATEREH KASHMARI ◽  
PRATHAMESH DESHPANDE ◽  
SAGAR PATIL ◽  
SAGAR SHAH ◽  
MARIANNA MAIARU ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Residual Stresses ◽  
Crystallization Kinetics ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Processing Parameters ◽  
Thermomechanical Properties ◽  
Volumetric Shrinkage ◽  
Processing Temperature ◽  
Wide Range

Polymer Matrix Composites (PMCs) have been the subject of many recent studies due to their outstanding characteristics. For the processing of PMCs, a wide range of elevated temperatures is typically applied to the material, leading to the development of internal residual stresses during the final cool-down step. These residual stresses may lead to net shape deformations or internal damage. Also, volumetric shrinkage, and thus additional residual stresses, could be created during crystallization of the semi-crystalline thermoplastic matrix. Furthermore, the thermomechanical properties of semi-crystalline polymers are susceptible to the crystallinity content, which is tightly controlled by the processing parameters (processing temperature, temperature holding time) and material properties (melting and crystallization temperatures). Hence, it is vital to have a precise understanding of crystallization kinetics and its impact on the final component's performance to accurately predict induced residual stresses during the processing of these materials. To enable multi-scale process modeling of thermoplastic composites, molecular-level material properties must be determined for a wide range of crystallinity levels. In this study, the thermomechanical properties and volumetric shrinkage of the thermoplastic Poly Ether Ether Ketone (PEEK) resin are predicted as a function of crystallinity content and temperature using molecular dynamics (MD) modeling. Using crystallization-kinetics models, the thermo-mechanical properties are directly related to processing time and temperature. This research can ultimately predict the residual stress evolution in PEEK composites as a function of processing parameters.

Effect of Substrate Temperature on Properties of Nano-Scale Functionally Graded Calcium Phosphate Coatings

2006 ◽  
Author(s):  
Travis Blalock ◽  
Xiao Bai ◽  
Afsaneh Rabiei
Keyword(s):  
Electron Microscopy ◽  
Calcium Phosphate ◽  
Substrate Temperature ◽  
Ion Beam ◽  
Processing Parameters ◽  
Functionally Graded ◽  
Cross Sectional ◽  
X Ray ◽  
Phosphate Coatings ◽  
Calcium Phosphate Coatings

The effect of substrate temperature and processing parameters on microstructure and crystallinity of calcium phosphate coatings deposited on heated substrates in an Ion Beam Assisted Deposition (IBAD) system are being studied. The experimental procedures include mechanical testing and film thickness measurements using bonding strength and profilometery. Cross-sectional scanning transmission electron microscopy (STEM) with energy dispersive X-ray spectroscopy (EDX) through the thickness of the film as well as scanning electron microscopy (SEM) with EDX at the top surface of the film was performed to evaluate the microstructure of the film. The coating crystallinity was studied through X-ray diffraction (XRD). The information gained from current analysis on the set temperature coatings will be used to refine the processing techniques of the Functionally Graded Hydroxyapatite (FGHA) coating.

Formation of the Cast Iron Coatings Plasma-Sprayed at Different Substrate Temperatures

2010 ◽  
Vol 44-47 ◽  
pp. 2144-2147
Author(s):  
Ya Zhe Xing ◽  
Chao Ping Jiang ◽  
Hong Chen ◽  
Jian Min Hao
Keyword(s):  
Cast Iron ◽  
Substrate Temperature ◽  
Phase Structure ◽  
Processing Parameters ◽  
Optical Microscope ◽  
Atmospheric Plasma ◽  
Cross Sectional ◽  
The Cross ◽  
Plasma Sprayed ◽  
Iron Coatings

In this work, three cast iron coatings were produced by atmospheric plasma spraying. During spraying, the surface temperature of three coatings (substrate temperature) was controlled to be averagely 50oC, 180oC and 240oC by changing the processing parameters. X-ray diffraction (XRD) was employed to analyze the phase structure of the starting powder and the coatings. The results showed that the powder was mainly composed of (Fe,Cr)7C3 and martensite and both the spraying processing and the substrate temperature exerted no influence on coating phase structure. An optical microscope (OM) was used to characterize the microstructure of the cross-section and surface of the coatings. It was found that the cross sectional hardness increased with the increase of the substrate temperature due to the improvement in interlamellar bonding.

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