Effects Of Different Sintering Temperatures Research Articles

Hybrid sintering of CNT/PZT ceramics using microwave oven

Piezoelectric materials play a major role in a variety of applications such as sensing, actuation and energy harvesting. Lead Zirconate Titanate (PZT) is a commonly used piezoelectric material because of its superior piezoelectric properties. One of the key elements to optimize the manufacturing process of this group of piezoelectric materials is minimizing the processing time and energy required to prepare ceramic parts. Among the production steps, the sintering process needs the most time and consumes the most energy. In this study, a rapid sintering method of bulk PZT elements is proposed based on microwaves. Carbon nanotubes (CNTs) are added to the material as an absorption aid. The effects of different sintering temperatures, microwave (MW) power and CNT weight fraction on the grain size, physical, mechanical and piezoelectric properties are investigated. The results show that higher MW powers lead to smaller grain sizes, higher mechanical properties but lower densities and electromechanical properties. The introduction of CNTs to the PZT material results in higher heating rates at the initial portion of the sintering process as well as smaller and more uniform grains while decreasing the density. The ceramic parts with 1 wt% CNTs concentration have the highest piezoelectric coefficient after sintering and poling. Generally, the proposed method is more environmentally friendly than the conventional method because not only does it require a lower processing time and energy, but also it leads to the formation of a single-phase perovskite structure without the need for additional amounts of lead.

Structural, optical, photoluminescence, and EPR behaviour of novel Zn0·80Cd0·20O thick films: An effect of different sintering temperatures

Zn0·80Cd0·20O (ZnCdO) alloy coated screen-printed films on glass substrates were sintered in muffle furnace at different temperatures (500 °C, 550 °C & 600 °C) for 10 min duration and probed by different analytical techniques to reveal the effect of sintering on their structure, optical and electrical characteristics. X-ray diffraction (XRD) patterns exhibit polycrystalline phases of both hexagonal ZnO and cubic (CdO) crystal structures with a maximum intensity along (101) diffraction plane. UV-VIS and photoluminescence (PL) absorbance peaks exhibit red shift in their respective spectra. Zn–O, Cd–O stretching modes were observed in infrared transmission spectra of the raw and sintered films in 4000–400 cm−1 region, respectively. EPR studies exhibit the formation of oxygen vacancies and inherent defect in the Cd alloyed ZnO composite developed during synthesis process. All the parameters such as particle size, optical constants, activation energies and paramagnetic oxygen vacancies have been affected by sintering temperature.

Sinter‐Crystallization and Optical Characterization of Dy 3+ : ZnO‐B 2 O 3 ‐RHA Glass‐Ceramics

In this current study, the behavior of dysprosium oxide (Dy2O3) doped willemite glass-ceramic (WGC) derived from ZnO-B2O3-RHA: Dy2O3 glasses and rice-husk ash (RHA) works as the active alternative silica has been studied. The fusions of the ternary host system of oxide components doped with rare earth oxide go through the melt-quench technique followed by solid-state sintering on the compacted glass frits. The sintered green samples are characterized utilizing the physical, structural, and optical properties to investigate the effect of different sintering temperatures on the samples accordingly. The bulk density of WGC increases together with the increment of sintering temperature from 2.571 to 2.940 g cm–3. Meanwhile, the increment of sintering temperature escalates the crystallization of the main crystalline phase, Zn2SiO4, corroborated by the enlargement of average crystallite size from 161 to 550 nm. Furthermore, the emission activity in the WGC also intensifies on the green emission region (524 nm) accordingly. This fabricated Dy3+:WGC contributes to the nomination as the potential solid-state lighting material.

Preparation, microstructure and compressive property of NiTi alloy hollow spheres fabricated by powder metallurgy

NiTi alloy hollow spheres were prepared using a powder metallurgy at 1100 °C, 1150 °C, 1170 °C and 1200 °C in vacuum sintering furnace. The effects of different sintering temperatures on thin-wall porosities, microstructural evolution and quasi-static compression properties of NiTi alloy hollow spheres were studied. The results showed that NiTi alloy hollow spheres with good surface quality are obtained at 1200 °C. The thin-wall porosity decreases with increasing sintering temperature, while the uniformity of thin-wall thickness increases. The number of pores decreases during sintering process, while the pores with large size grow bigger and become spherify. The NiTi alloy hollow spheres mainly consist of the predominant NiTi phase (B2 and R), and precipitated phases Ti2Ni, Ni3Ti and Ni4Ti3. The size of Ti2Ni increases first and then decreases with increasing sintering temperature, while the Ni3Ti phase continuously and uniformly precipitates at grain boundary. Compressive strength of NiTi alloy hollow spheres increases with increasing sintering temperature, and increases to 189 MPa when sintering temperature reaches to 1200 °C. The loading-unloading curves of hollow spheres revealed that the hollow spheres show superelastic behavior to a certain extent. The fracture characteristics of sintered NiTi alloy hollow spheres were also addressed in this work.

Effect of sintering temperature on microstructure and properties of MIM420 stainless steel

ABSTRACT This paper investigates the effect of different sintering temperatures on the microstructure and mechanical properties of 420 stainless steel prepared by metal injection molding (MIM). The results show that in the temperature range of 1300 to 1360, the internal structure of MIM420 stainless steel is mainly lath martensite and the fracture mode is quasi cleavage fracture. With the increase of sintering temperature, the relative density, strength and hardness of MIM420 stainless steel increase, and the carbon and oxygen content decreases, but the strength decreases when the sintering temperature exceeds 1340. When the sintering temperature reaches 1360, the sample will be slightly over sintered, so the appropriate sintering temperature is 1340. At 1340, the relative density, hardness, bending strength and ultimate tensile strength of the sample are 98.2 ± 0.4%, 54 ± 1HRC, 1229 ± 28 MPa and 1111 ± 26 MPa respectively.

Enhanced Mechanical and Fatigue Properties In AA5052 Via TiO_2 Nanoparticles Addition Sintering Temperature (ST)

The goal of the present work is to study the effect of different sintering temperatures (900, 1000 and 1100 ) on fatigue and mechanical characteristics of the metal matrix AA5052 reinforced with 5% of TiO2 nanoparticles. The stir casting process is used for manufacturing of AA5052/TiO2 nanocomposite. The mechanical characteristics of nano composites have been obtained at ambient temperature. The results of mechanical properties showed that the best enhancement in hardness (HB), ultimate tensile strength (UTS) and yield strength (YS) is occurred in nanocomposite with 1000 sintering temperature (ST). However, the fatigue test results showed that the samples manufactured under 1000 (ST) have longer fatigue life compared to other materials with different sintering temperatures. The endurance fatigue strength is improved by 7.2% compared to metal matrix. The experimental results showed that the microstructure image of 1000 (ST) composite has uniformly distributed of TiO2 in AA5052 matrix.

Crystal structure and XANES study of Fe-substituted Barium Titanate ceramics prepared by conventional solid-state technique

The structural characterizations of Fe-substituted Barium Titanate (Fe–BaTiO3) ceramics prepared at different sintering temperatures were investigated in this work. The Fe–BaTiO3 ceramics (with 10 mol% of Fe substitution) were prepared via a conventional solid-state reaction (SSR) method. The structural data were examined by XRD (X-ray Diffraction) and XAS (X-ray Absorption Spectroscopy) techniques. The results revealed the transformation from tetragonal to hexagonal structure with increasing sintering temperature. The measured XANES (X-Ray Absorption Near-Edge Structure) data exhibited the oxidation state of Fe ion as Fe3+ in the Fe–BaTiO3. The comparison between measured and calculated XANES spectra to examine the effect of different sintering temperatures on the local structure around the Ti atom was carried out. Finally, it should be emphasized that the local structure evolution in Fe–BaTiO3 ceramics may be explored by the XANES investigations.

Low-temperature sintering of a porous SiC ceramic filter using water glass and zirconia as sintering aids

The fabrication of porous silicon carbide (SiC) ceramics prepared by existing reaction bonding technology requires high-temperature sintering beyond 1400 °C. We used low-cost industrial grade water glass and zirconia as sintering aids to prepare porous SiC ceramic filters to reduce the sintering temperature while improving the commerciality. Additionally, we investigated the effects of different sintering temperatures and the addition of water glass on the samples. Loading water glass and zirconia reduced the sintering temperature to 600 °C. The additive-loaded ceramic filter sintered at 600 °C exhibited an average pore size of 0.58 μm, a porosity of 47.4%, a bending strength reaching 56 MPa, a pure water permeance exceeding 4800 L m−2h−1bar−1, and good acid corrosion resistance. In addition, the SiC filter prepared at 1000 °C showed good chemical resistance and an average pore size of 0.75 μm as well as mechanical strength and pure water permeance of over 80 MPa and 6294 L m−2h−1bar−1, respectively. The low-cost, high-performance porous SiC ceramic filter exhibits broad commercial application prospects in water treatment.

Facile synthesis and luminescence properties of tubular BCNO phosphor with orange emission assisted by bamboo fiber

In this work, tubular boron carbon oxynitride (BCNO) phosphors with orange-emitting are synthesized by bamboo fiber assistance. The effects of different sintering temperatures on the structure, morphology, and photoluminescence (PL) performance of BCNO phosphors were investigated. The results revealed that with the increase of sintering temperature, compared with the BCNO synthesized without the template, the synthesized BCNO phosphor with bamboo fiber as template gradually becomes a hollow tubular structure. Meanwhile, when the sintering temperature is 700 ℃, the BCNO phosphor shows bright orange emission at 315 nm excitation wavelength, and the quantum yield (QY) is up to 75%. Moreover, the prepared BCNO phosphor has a sensitive and selective quenching effect on Fe3+ ion under 365 nm portable ultraviolet lamp irradiation. By using the obtained BCNO phosphor as a fluorescence labeling marker, the fingerprint recognition on the object surfaces also could be realized.

Impact of changes in sintering temperatures on characteristics of 4YSZ and 5YSZ

ObjectivesThe aim of this study was to evaluate the effect of different sintering temperatures on biaxial flexural strength (BFS), dynamic loading, surface hardness, color reproduction, translucency, surface roughness and microstructure of zirconia with 4 mol% yttria (4YSZ) compared to zirconia with 5 mol% yttria (5YSZ). MethodsZirconia discs with 12 mm diameter and 1.2 mm thickness were prepared and divided into three groups (n = 53) according to different sintering temperatures (1400 °C, 1500 °C and 1600 °C). Each group was divided into five subgroups (n = 10) according to the dynamic loading procedure (none, 50%, 65%, 75% and 80%) conducted before the quasi-static BFS test and another subgroup (n = 3) used for X-ray-diffraction (XRD) microstructure analysis. BFS test and dynamic loading were performed with a piston-on-three-ball test. The surface hardness was evaluated according to Vickers. Color reproduction and translucency were measured with a spectrophotometer. A 3D laser scanning microscope was used to determine the surface roughness. Grain size measurements were performed using SEM. ResultsA significant increase in biaxial flexural strength was observed while the sintering temperature decreased. 4YSZ had significantly higher results in biaxial flexural strength than 5YSZ. A decrease in sintering temperature resulted in a significant increase in Vickers hardness. Furthermore, 4YSZ showed significantly better color reproduction with increasing sintering temperature. At higher temperatures (1500 °C and 1600 °C), 4YSZ showed better color reproduction than 5YSZ. Compared to 4YSZ, specimens of 5YSZ exhibited significant higher translucency. Using XRD, a distorted tetragonal phase was detected in addition to regular tetragonal and cubic phases in specimens without any stress and at a low sintering temperature. The grain sizes of both materials increased with an increase in sintering temperature. ConclusionThe sintering temperature has significant effects on the microstructure and thus on the mechanical and optical properties of the evaluated zirconia.

Fabrication and upconversion luminescence properties of Er:SrF2 transparent ceramics compared with Er:CaF2

SrF2 transparent ceramic is a promising upconversion material due to the low phonon energy. The effect of different sintering temperatures on Er:SrF2 transparent ceramics was investigated. The suitable sintering temperature for Er:SrF2 transparent ceramics was 900 °C by hot-pressed sintering in this study. High quality of Er:SrF2 transparent ceramics with different doping concentrations were obtained. The upconversion luminescence spectra and decay behavior were compared between Er:SrF2 and Er:CaF2 transparent ceramics with different Er3+ doping concentration. The green emission of 5 at.% Er:SrF2 ceramic was much stronger than that of 5 at.% Er:CaF2 ceramic, while the red emission of Er:SrF2 ceramic was almost the same as that of Er:CaF2 ceramic. The upconversion luminescence lifetime of Er:SrF2 transparent ceramics was longer than that of Er:CaF2.All the results indicated Er:SrF2 transparent ceramics was a candidate for green fluorescent upconversion materials.

Effect of the microstructure and properties of graphite/copper composites fabricated by microwave sintering

In this study, graphite/copper composites were prepared by microwave sintering. The microstructure and properties of the composites were characterized. The effects of different sintering temperatures on the properties of the composites were studied, and the differences between microwave sintering and conventional sintering composites were compared. The results show that after microwave sintering, the grain size of the copper matrix is refined and the graphite/copper interface is improved, and the distribution of graphite over the matrix becomes more uniform. Compared with conventional sintering, the properties of microwave-sintered samples have been further improved. Besides, with the increase in sintering temperature, the density, hardness, electrical conductivity and thermal conductivity of the composite have been improved, and some properties have become anisotropic obviously. Thus, the electrical conductivity and thermal conductivity along the direction of graphite sheet are higher than those perpendicular to the sheet.

Effect of V2O5 B-site substitution on the microstructure, Raman spectrum, and dielectric properties of SrBi2Ta2O9 ceramics

Strontium bismuth tantalate vanadate [SrBi2(Ta2−xVx)O9, SBTV] ceramics, which are bismuth-layered perovskite ferroelectrics, were synthesized through the solid-state reaction method. The effects of different sintering temperatures and V2O5 contents on the structure of the microstructure, Raman spectrum, and dielectric properties of the SBTV ceramics were investigated. As sintered at high temperature (980–1040 °C) and different V2O5 contents (x = 0.1 − x = 0.4), only disk-like grains of the SBTV ceramics were observed in the scanning electron micrographs. Preferential orientation of the crystals of the SBTV ceramics was confirmed through X-ray diffraction studies. The higher dielectric constant and Curie temperature of the SBTV ceramics compared with those of strontium bismuth tantalite (SrBi2Ta2O9, SBT) ceramics are ascribe to the partial replace of Ta5+ ions by V5+ ions in the B sites. The Curie–Weiss law and the modified Curie–Weiss law were used to discuss the normal-type or relaxor-type ferroelectric characteristic of the SBTV ceramics. The Ta5+ ion replaced by V5+ ion site in SBT ceramics to form SBTV ceramics exerted a pronounced effect on the BO6 mode, as demonstrated by Raman spectrum results.

Environmental risks and mechanical evaluation of recycling red mud in bricks

More and more by-products are being used in certain materials, especially in the construction industry. Natural construction materials contain amounts of heavy metals and radionuclides, but when by-products are used in these kinds of materials, this could lead to a growth in their concentrations and have a negative impact on public health.In this paper, red mud was used as a raw material (as a clay substitute) to manufacture fired bricks. Physical, mechanical, radiological and heavy metal leaching properties of fired bricks with a replacement ratio of up to 80 wt% of clay to red mud are discussed. In addition, the effect of different sintering temperatures (1173K and 1373K) was analyzed, and results showed that the higher the temperature produced, the higher the mechanical strength.To environmentally characterize materials, they were subjected to two different leaching tests: a batch test for raw materials and a monolithic test for the bricks, respectively. The results obtained were compared with the limits stated for several heavy metals by the European Landfill Directive. Results showed that red mud gives leachate concentration values for Cr higher than the limits stated for non-hazardous by-products. Bricks do not exhibit the same problem in the samples containing a high RM proportion and manufactured at a low sintering temperature (1173K), although in the case of V, a high concentration is observed.The contents of radionuclides such as Ra-220, Th-232 and K-40 of the final construction materials were analyzed and compared with different indexes. This paper indicates the maximum amounts of RM that can be used to replace clay for the manufacture of fired bricks without environmental risk.

The Effect of Different Sintering Temperature and Time on Tribological and Mechanical Properties in Non Asbestos Brake Pad Manufacturing

Otomotiv fren balataları birçok farklı malzemenin birleşiminin sinterlenmesi ile üretilmektedir. Baltaların farklı üretim parametreleri ile üretildikleri akademik çalışmalardan görülmektedir. Bu çalışmada, farklı sıcaklıklarda ve farklı sürelerde sinterleme ile imal edilen asbest içermeyen balataların, tribolojik ve mekanik özellikleri araştırılmıştır. Üretilen balataların sürtünme katsayısı, kesme dayanımı, özgül aşınma değerleri, sıcaklığı, sertlik değerleri, yoğunluğu ölçülmüş ve SEM/EDS analizi yapılarak farklı sinterleme sıcaklığı ve sürelerinin etkileri gözlemlenmiştir. Sinterleme sıcaklığı ve süresindeki artışın balata sürtünme katsayısı, özgül aşınma oranı, kesme gerilme değerleri ve balata sıcaklık değerleri açısından olumlu olduğu tespit edilmiştir.

Effect of sintering temperature on microstructure, flexural strength, and optical properties of a fully stabilized monolithic zirconia

Statement of problemFully stabilized monolithic zirconia (FSZ) has been developed as an alternative to zirconia veneered with porcelain. However, how sintering conditions might affect its microstructure and optical and mechanical properties is unclear. PurposeThe purpose of this in vitro study was to determine the effect of different sintering temperatures on the microstructure and optical and mechanical properties of FSZ. Material and methodsBar-shaped FSZ specimens were prepared and divided into 2 groups (n=15) according to final sintering temperatures (1450 °C and 1600 °C). The average reflectance, opacity, translucency parameter, and sum of light absorption-scattering values were obtained by using a spectrophotometer, and ΔE00 was calculated. The 3-point bend test was performed in a universal testing machine. Scanning electron microscopy (SEM) was conducted for microstructure analysis. Crystalline phase quantification was obtained by X-ray diffraction (XRD). Data were analyzed by using D'Agostino-Pearson and Student t tests (α=.05). ResultsA significant difference was detected in the reflectance and sum of light absorption-scattering values between the 2 groups. The translucency parameter, opacity, and flexural strength showed no statistical differences. ΔE00 was 0.98. XRD indicated cubic (47.41% for 1450 °C; 46.04% for 1600 °C) and tetragonal content (52.59% for 1450 °C; 53.96% for 1600 °C). No monoclinic content was found. SEM images showed more definite grain boundaries in the 1600-°C group. Mean grain size was 0.49 μm for the 1450-°C group and 1.99 μm for the 1600-°C group. ConclusionsHigher sintering temperatures increased the grain size but did not change the crystal phase concentration. A significant difference was found in the reflectance and sum of light absorption-scattering, but no differences were found among the translucency parameter, opacity, or flexural strength.

Impact of sintering temperature and pH of feed solution on adsorptive removal of ammonia from wastewater using clinoptilolite based hollow fibre ceramic membrane

This work presented the adsorptive hollow fibre ceramic membrane (HFCM) derived from clinoptilolite for effective removal of ammonia from water. The effect of different sintering temperature of HFCM (900–1150 °C) and pH of ammonia feed solution (pH 2 – pH 11) were examined. The membranes were fully characterized by the scanning electron microscopy (SEM), mechanical strength, water permeability, X-ray diffraction (XRD), X-ray fluorescence (XRF) and zeta potential to get the better understand of its physicochemical properties and ammonia adsorption mechanism relationship. The best fabricated HFCM was produced when sintered at 1050 °C with 54.20 MPa and 228.25 L/m2·h of mechanical strength and water permeability, respectively. The adsorption kinetics behavior showed that the adsorption process was best fitted to pseudo-second order kinetic model with 12.468 mg/g adsorption capacity. The morphology and negatively charged surface of the HFCM have significantly contributed to the high adsorption of the ammonia (96.67 %) from the feed solution. The maximum adsorption activities were achieved at pH 7 with 0.4 g/L HFCM within 120 min of residence time. The results indicated that the adsorptive HFCM have significant potential to be developed as simple, economical and effective remover for the ammoniacal wastewater treatment.

The preparation and mechanical properties of nano-magnesium alloy bulks

In this paper, nanocrystalline (nc) AZ91 magnesium alloy bulks, with average grain sizes of ∼15 nm, were processed via the combined processing of hydrogenation-disproportionation-desorption-recombination (HDDR), spark plasma sintering (SPS) and hot extrusion. The effects of different sintering temperatures and holding times on the sintering properties of magnesium alloy were analyzed and the optimum SPS sintering process parameters of nanocrystalline AZ91 powder were determined. The tensile strength of nc AZ91 magnesium alloy rods is up to 267 MPa at room temperature. Meanwhile, when the grain size is less than 20 nm the particular mechanical behavior of nc magnesium alloy emerged, which implies an inverse Hall-Petch relationship.

Correlation between B value deviation and sintering temperature of perovskite solid solution materials

AbstractThe effects of different sintering temperatures on the system of Ba0.5Sr0.5TiO3–La0.8Ca0.2MnO3 (BST‐LCM) material were investigated by means of scanning electron microscopy, X‐ray, resistance‐temperature measurements, and X‐ray photoelectron spectroscopy. X‐ray diffraction and X‐ray photoelectron spectroscopy confirm that BST‐LCM is completely miscible and BST is the main phase, which under the premise of following the theory of small polaron conduction, titanium ions interact with manganese ions, which affects the electrical properties of the system of BST‐LCM material. For the electrical properties of related, the LCM content is inversely proportional to the activation energy. Through the linear fitting of the experimental data, the empirical formula between the sintering temperature B value and the content of solid solution is obtained, and the approximate B value within a certain range can be preliminarily calculated.

Effect of Different Sintering Temperatures on Structural and Magnetic Properties of Zn–Co Ferrite Nanoparticles

In order to investigate the effect of sintering temperature on the structure and properties of Zn–Co ferrite, the Zn0.5Co0.5Fe2O4 ferrite powder with spinel structured was prepared by sol–gel method at different sintering temperatures. X-ray diffraction spectroscopy (XRD), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) were used to study the structural and magnetic properties of the prepared samples. It was found that the sintering temperature has a significant influence on the structure and magnetic properties of the Zn–Co ferrite. As the sintering temperature increases from 600 to 1000 °C, the crystallinity and crystallite size of the samples increase significantly, but the coercivity, remanence, and squareness decrease and the saturation magnetization increases first and then decreases. Compared with other samples, the sample sintered at 900 °C has the highest bulk density (3715.42 kg/m3) and saturation magnetization (68.17 emu/g). At the same time, it also has a small coercivity, remanence, anisotropy constant, and porosity. The sample obtained by sintering at 800 °C has a good magnetic susceptibility (dM/dH) at Hm. This work provides basic research data for the preparation of Zn–Co ferrite with better magnetic properties and has certain reference value.