scholarly journals Processing Analysis of Nanoparticle Filled PTFE: Restrictions and Limitations of High Temperature Production

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2044
Author(s):  
Levente Ferenc Tóth ◽  
Patrick De Baets ◽  
Gábor Szebényi
Keyword(s):  
Thermal Stability ◽  
Mass Loss ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Research Work ◽  
Decomposition Analysis ◽  
High Thermal Stability ◽  
Al2o3 Content ◽  
Sintering Process ◽  
Sintering Method

In this research work, unfilled and monofilled polytetrafluoroethylene (PTFE) were investigated. The applied fillers were graphene, alumina (Al2O3), boehmite alumina (BA80) and hydrotalcite (MG70). Graphene and Al2O3 are already known in the literature as potential fillers of PTFE, while BA80 and MG70 are novel fillers in PTFE. Materials were produced by room temperature pressing—free sintering method with a maximum sintering temperature of 370 °C. The mass loss and decomposition analyses were carried out by thermogravimetric analysis (TGA) in two different ways. The first was a sensitivity analysis to gain a better view into the sintering process at 370 °C maximal temperature. The second was a heating from 50 °C up to 1000 °C for a full-scale decomposition analysis. BA80 is a suitable filler for PTFE, as most of its functional groups still existed after the sintering process. Both PTFE and Al2O3 had high thermal stability. However, when Al2O3 was incorporated in PTFE, a remarkable mass loss was observed during the sintering process, which indicated that the decomposition of PTFE was catalysed by the Al2O3 filler. The observed mass loss of the Al2O3-filled PTFE was increased, as the Al2O3 content or the applied dwelling time at a 370 °C sintering temperature increased.

scholarly journals Thermal, Viscoelastic, Mechanical and Wear Behaviour of Nanoparticle Filled Polytetrafluoroethylene: A Comparison

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1940 ◽  
Author(s):  
Levente Ferenc Tóth ◽  
Patrick De Baets ◽  
Gábor Szebényi
Keyword(s):  
Room Temperature ◽  
Filler Content ◽  
Research Work ◽  
Tensile Modulus ◽  
Al2o3 Content ◽  
Wear Behaviour ◽  
X Ray ◽  
Mechanical Stirring ◽  
Wear Analysis ◽  
Sintering Method

In this research work, unfilled and mono-filled polytetrafluoroethylene (PTFE) materials were developed and characterised by physical, thermal, viscoelastic, mechanical, and wear analysis. The applied fillers were graphene, alumina (Al2O3), boehmite alumina (BA80), and hydrotalcite (MG70) in 0.25/1/4/8 and 16 wt % filler content. All samples were produced by room temperature pressing–free sintering method. All of the fillers were blended with PTFE by intensive dry mechanical stirring; the efficiency of the blending was analysed by Energy-dispersive X-ray spectroscopy (EDS) method. Compared to neat PTFE, graphene in 4/8/16 wt % improved the thermal conductivity by ~29%/~84%/~157%, respectively. All fillers increased the storage, shear and tensile modulus and decreased the ductility. PTFE with 4 wt % Al2O3 content reached the lowest wear rate; the reduction was more than two orders of magnitude compared to the neat PTFE.

Effect of Sintering Process on Microstructures and Dielectric Properties of Nb-Doped BaTiO3-(Bi0.5Na0.5)TiO3 Ceramics for X9R MLCC Applications

2018 ◽  
Vol 281 ◽  
pp. 634-639
Author(s):  
Ling Ling Chen ◽  
Zheng Bo Shen ◽  
Qian Cheng Zhao ◽  
Zi Ming Cai ◽  
Xiao Hui Wang ◽  
...  
Keyword(s):  
Screen Printing ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Tape Casting ◽  
Sintering Process ◽  
Ceramic Capacitor ◽  
Conventional Sintering ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Sintering Method

Multilayer ceramic capacitor (MLCC) chips have been successfully prepared through tape-casting and screen-printing. Conventional sintering method and two-step sintering method with different sintering temperature and holding time are used to obtain the MLCC chips. The scanning electron microscopes show that MLCC chips sintered by two-step sintering at T1=1200°C and T2=1130°C for 3h have a highly dense dielectric layer. The temperature coefficient of capacitance (TCC) of the MLCC chip is less than ±15% from-60°C to 235 °C that satisfactorily meets the requirement of X9R. The average capacitance and the dielectric loss of the MLCC chip are 88nF and 1.8% at the room temperature, respectively.

scholarly journals Effects of Substitution of Y with Yb and Ce on the Microstructures and Mechanical Properties of Mg88.5Zn5Y6.5

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 31
Author(s):  
Hongxin Liao ◽  
Taekyung Lee ◽  
Jiangfeng Song ◽  
Jonghyun Kim ◽  
Fusheng Pan
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Creep Resistance ◽  
Room Temperature ◽  
High Thermal Stability ◽  
Long Period ◽  
Microstructures And Mechanical Properties

The microstructures and mechanical properties of the Mg88.5Zn5Y6.5-XREX (RE = Yb and Ce, X = 0, 1.5, 3.0, and 4.5) (wt.%) alloys were investigated in the present study. Mg88.5Zn5Y6.5 is composed of three phases, namely, α-Mg, long-period stacking ordered (LPSO) phases, and intermetallic compounds. The content of the LPSO phases decreased with the addition of Ce and Yb, and no LPSO phases were detected in Mg88.5Zn5Y2.0Yb4.5. The alloys containing the LPSO phases possessed a stratified microstructure and exhibited excellent mechanical properties. Mg88.5Zn5Y5.0Ce1.5 exhibited the highest creep resistance and mechanical strength at both room temperature and 200 °C, owing to its suitable microstructure and high thermal stability. The yield strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature was 358 MPa. The ultimate tensile strength of Mg88.5Zn5Y5.0Ce1.5 at room temperature and 200 °C was 453 MPa and 360 MPa, respectively.

Effect of Sintering Temperature on Properties of YAG Porous Ceramics via Atmospheric Sintering Method

2018 ◽  
Vol 281 ◽  
pp. 224-229 ◽  
Author(s):  
Fang Wang ◽  
Ming Han Xu ◽  
Ai Xia Chen ◽  
Long Tao Liu ◽  
Zhi Hui Li ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Raw Materials ◽  
Porous Ceramics ◽  
Soluble Starch ◽  
Product Performance ◽  
Effect Of Temperature ◽  
Sintering Process ◽  
Molding Process ◽  
Sintering Aid ◽  
Sintering Method

YAG materials have a number of unique properties, the application is very extensive, the burn is due to the temperature is too high or the residence time at high temperatures is caused. The undercurrent is the sintering temperature is too low or the holding time is not enough, resulting in product performance is too low or too small shrinkage. In this paper, the effect of sintering temperature on properties of YAG porous ceramics was investigated. The results showed that the firing temperature of the ingredients will be different and cause the same sintering process and sintering additives content of different samples burned. The increase in the content of SiO2 in the furnish with the sintering aid tends to occur. the effect of temperature on the mechanical properties of the samples after sintering was significant, so the raw materials include 60wt%YAG, 10wt% CaO, 10wt% SiO2 and 20wt% soluble starch, the molding process in 20MPa pressure 10min, the sintering at 1500°C for 2h, the sample porosity is 42.2%, the compressive strength is 5.8MPa, the outside shape is keep intact and the better pore microstructure is shown.

scholarly journals ON/OFF Photostimulation of Isatin Bipyridyl Hydrazones: Photochemical and Spectral Study

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2668 ◽  
Author(s):  
Róbert Šandrik ◽  
Pavol Tisovský ◽  
Klaudia Csicsai ◽  
Jana Donovalová ◽  
Martin Gáplovský ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Spectral Study ◽  
Photochemical Reaction ◽  
Room Temperature ◽  
High Thermal Stability ◽  
Light Stimulation ◽  
Fluoride Ions ◽  
Isomerization Process

Four novel isatin hydrazones containing bipyridyl fragments were synthesized as potential ON/OFF switches. Hydrazone Z-isomers exhibit high thermal stability. The characteristic photochemical reaction for all studied hydrazones is the Z–E isomerization in CHCl3. After irradiation of hydrazones 1 and 2 in dimethylformamide (DMF), the photoreaction products are tautomers. When using light with the appropriate wavelength, the photo-tautomerization reaction is reversible. In these conditions, studied hydrazones have ON/OFF switch properties. In the case of hydrazones 1 and 2, by alternating heat and light stimulation it is possible to control the isomerization process reversibly. In the presence of fluoride ions, NH hydrogen from the studied hydrazones is cleaved, and the corresponding anions are formed. The resulting anions of Z-isomers are changed to the corresponding E-isomer at room temperature.

PHASE STRUCTURE, PIEZOELECTRIC AND MULTIFERRIOC BEHAVIOR OF (K0.48Na0.52)NbO3-Co2O3 PIEZOELECTRIC CERAMICS

2011 ◽  
Vol 04 (03) ◽  
pp. 225-229 ◽  
Author(s):  
WENJUAN WU ◽  
DINGQUAN XIAO ◽  
JIAGANG WU ◽  
JING LI ◽  
JIANGUO ZHU
Keyword(s):  
Room Temperature ◽  
Sintering Temperature ◽  
Magnetic Behavior ◽  
Orthorhombic Phase ◽  
Piezoelectric Ceramics ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Solid State Sintering ◽  
Sintering Method

( K 0.48 Na 0.52) NbO 3-x% Co 2 O 3 (x = 0, 0.03 and 0.05) (KNN-x% Co2O3 ) lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. An orthorhombic phase was observed for all KNN-x% Co2O3 ceramics at room temperature, and two phase transitions were confirmed by the high temperature X-ray diffraction and the temperature dependence of the dielectric constant. The Co2O3 greatly improves the density and decreases the sintering temperature of KNN ceramics. The KNN-0.05 mol%Co2O3 ceramic exhibits good properties (d33 = 120 pC/N , k p = 0.41, Q m = 213 and T c = 407°C) and a good age stability. The multiferroic behavior was also observed at room temperature for the KNN-0.05 mol%Co2O3 ceramic, as confirmed by P–E loops and magnetic behavior.

Influence of Glassy Additives on the Formation of Crystalline Phases in Sintered Red Ceramic Bodies

2015 ◽  
Vol 1765 ◽  
pp. 77-82
Author(s):  
A.F. Chávez-Villanueva ◽  
G. Vargas-Gutiérrez ◽  
J. López-Cuevas ◽  
C.M. López-Badillo
Keyword(s):  
Sintering Temperature ◽  
Research Work ◽  
Soda Lime ◽  
Glass Frit ◽  
Sem Analysis ◽  
Soda Lime Glass ◽  
Nominal Composition ◽  
Sintering Process ◽  
Crystalline Phases ◽  
Floor Tiles

ABSTRACTThe main objective of this research work was to study the influence of glassy additives on the formation of crystalline phases in sintered red ceramic bodies used for the fabrication of ceramic floor tiles, whose composition is a mixture of quartz (SiO2), kaolinite [Al2Si2O5(OH)4], albite (NaAlSi3O8), muscovite [KAl2(Si3Al)O10(OH)2] and calcite (CaCO3). The additives used were: fly ash, soda-lime glass, borosilicate glass, glass frit, Na2P3O10 and cryolite (Na3AlF6). These were added in variable proportions to the nominal composition of the red ceramic bodies, either as single or as combined additions, aiming to accelerate the densification of the materials during their sintering process. For all the additive types used, the crystalline phases formed in the samples sintered using a peak temperature ranging from 950 to 1030 °C were: quartz (SiO2), anorthite (CaAl2Si2O8), and hematite (Fe2O3). It is known that the presence of anorthite is particularly beneficial for the mechanical properties, chemical stability and densification of the sintered red ceramic bodies. However, some of the considered additions tended to be detrimental for the formation of this phase in the studied materials, especially at the lowest peak sintering temperature employed. This was verified by means of XRD and SEM analysis.

scholarly journals Effect of Thermodynamic Melt Formation Characteristics on Liquid Phase Fluidity of Iron Ore in the Sintering Process

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 404 ◽  
Author(s):  
Shengli Wu ◽  
Heping Li ◽  
Weili Zhang ◽  
Bo Su
Keyword(s):  
Liquid Phase ◽  
Iron Ore ◽  
Sintering Temperature ◽  
Mixed Phase ◽  
Al2o3 Content ◽  
Phase Content ◽  
Sintering Process ◽  
Test Device ◽  
Sintering Characteristics ◽  
Factsage Software

The liquid phase fluidity of iron ore is a vital index of fundamental sintering characteristics. In this paper, FactSage software and a visible microsintering test device were used to research the influence of the thermodynamic melt characteristics on the liquid phase fluidity under fixed CaO content conditions. The results show that the laws governing liquid phase fluidity of iron ore are significantly different with a fixed alkalinity and fixed CaO content of the sample. The liquid phase content at the sintering temperature is the most important thermodynamic melt formation characteristic affecting the liquid phase fluidity. In addition to the liquid phase content, other minerals also have a greater impact on liquid phase fluidity. Decreasing the viscosity of the liquid phase improves the liquid phase fluidity of the iron ore, and the effect of the SiO2 content of the iron ore on the mixed phase viscosity is greater than that of the Al2O3 content.

Mechanical Properties of SiC/FexSiy Composites

2011 ◽  
Vol 236-238 ◽  
pp. 1523-1527 ◽  
Author(s):  
Xiao Meng Zhang ◽  
Shu Feng Ye ◽  
Li Hua Xu ◽  
Peng Qian ◽  
Lian Qi Wei ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Flexural Strength ◽  
Fracture Behavior ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Raw Material ◽  
Reaction Sintering ◽  
Sintering Process ◽  
Scanning Electron

The SiC/FexSiycomposites were synthesized by reaction sintering process with iron tailings as raw material and carbon as reductant. The room and high temperature flexural strengths and fracture toughness of composites were studied in this paper. Fracture surfaces were observed by means of a scanning electron microscope (SEM). The results showed that the room temperature flexural strength of SiC/FexSiycomposites changed along with the different contents of FexSiyand sintering temperature. The flexural strength of composites reaches the maximum at 900°C. The correlation between flexural strength and temperature is consistent with curveⅠ.The fracture toughness of composites is related to the content of FexSiy. The fracture behavior of composites is mainly transcrystalline in room temperature and intercrystalline in high temperature.

scholarly journals Electrical Conductivity and Nyquist Plot of C4C1Im BF4 at Room Temperature by Impedance Spectroscopy

2020 ◽  
Vol 3 (1) ◽  
pp. 119
Author(s):  
Pablo Vallet ◽  
Juan José Parajó ◽  
Félix Sotuela ◽  
Angel Morcillo ◽  
María Villanueva ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electrical Conductivity ◽  
Ionic Liquids ◽  
Ionic Conductivity ◽  
Impedance Spectroscopy ◽  
Vapour Pressure ◽  
Room Temperature ◽  
Nyquist Plot ◽  
High Thermal Stability ◽  
Wide Potential

Ionic liquids (ILs) represent a real alternative for electrochemical applications due to their remarkable characteristics, namely a very low vapour pressure, low flammability, high thermal stability, wide potential window and high ionic conductivity. In this work, Nyquist plot and impedance spectroscopy at room temperature is proposed as an alternative method to obtain the ionic conductivity for ionic liquids by using an Agilent HP 4284A RLC precision meter. For this propose, the IL 1-butyl-3-methylimidazolium tetrafluoroborate (C4C1Im BF4) was selected and results were compared with the previously obtained from the conductimeter CRISON GLP31.

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