Influence Of Sintering Parameters Research Articles

Preparation of coal gangue based foamed ceramics with SiC as blowing agent and study on its thermal insulation performance

The main objective of this study was to utilize coal gangue as the primary raw material and SiC as the foaming agent to successfully prepare foamed ceramics using the high-temperature foaming method. The study investigated the composition and crystal phases of the foamed ceramics formulation, the influence of sintering parameters on the microstructure and physical properties of the samples, as well as the reaction mechanisms during the foaming process. The experimental results showed that when the SiC addition amount was 2.5 wt%, the sintering temperature was 1230°C, and the sintering time was 60 min, the bulk density of the foamed ceramics reached as low as 0.414 g/cm3, with a compressive strength of 1.64 MPa and a closed porosity as high as 74.86%. Additionally, the water absorption and thermal conductivity were simultaneously reduced to 1.48% and 0.1968 W/(m·K), respectively. Besides maximizing the utilization of coal gangue, foamed ceramics also demonstrated excellent porous structure and physical properties, making them suitable for use as thermal insulation materials.

Research on the Preparation of Zirconia Coating on Titanium Alloy Surface and Its Tribological Properties

Titanium alloys have been widely used in aerospace and other fields due to their excellent properties such as light weight and high strength. However, the extremely poor tribological properties of titanium alloys limit their applications in certain special working conditions. In order to improve the tribological properties of titanium alloys, the zirconia coatings were prepared on the surface of a TC4 titanium alloy using the discharge plasma sintering method in this article. The influence of sintering parameters on properties such as density, adhesion, hardness, and phase composition, as well as tribological properties (friction coefficient, wear rate) were investigated, and the influence mechanism of the coating structure on its mechanical and frictional properties was analyzed. The results showed that, with the increase in sintering temperature, the density, bonding strength, and hardness of the zirconia coating were significantly improved. The zirconia coating prepared at a sintering temperature of 1500 °C and a sintering time of 20 min had the lowest friction coefficient and wear rate, which are 0.33 and 6.2 × 10−8 cm3·N−1·m−1, respectively. Numerical analysis showed that the increase in temperature and the extension of time contributed to the extension of the diffusion distance between zirconia and titanium, thereby improving the interfacial adhesion. The influence mechanism of different sintering temperatures and sintering times on the wear performance of zirconia coatings was explained through Hertz contact theory.

Fabrication of micro-ultrasonic phased array electrode via electric field-driven printing method

The electrode is an important part of a micro-ultrasonic phased array, commonly fabricated by magnetron sputtering technology. However, with the expansion of the application field, the structures of the phased arrays are becoming more complex, making the traditional magnetron sputtering method no longer applicable, and the realization of micro-scale phased array electrodes by direct printing technology still faces great challenges. Herein, an electric field-driven direct printing method was proposed to fabricate micro-ultrasonic phased array electrodes. The influence of sintering parameters on the resistivity and the effect of printing parameters on the geometric size and surface morphology of the electrode were comprehensively explored, and the mathematical model between the electrode line width and the printing parameters was established. The final printed electrodes exhibit superior properties with a resistivity of 2.4 × 10−7 Ω⋅m , a surface roughness range of 460–550 nm, and a line width range of 125–480 µm. Additionally, a micro-scale electrode was printed on the piezoelectric ceramic with PZT-5 as the material, and after polarization treatment, the piezoelectric coefficient can reach 405 pC N−1, which proves that this method can be applied in the field of fabricating phased array electrodes.

Effect of full melt temperature sintering and semi-melt heat preservation sintering on microstructure and mechanical properties of Ti3SiC2/Cu composites

The influence of sintering parameters on the microstructure, phase composition and mechanical property of the Ti3SiC2/Cu composites sintered by spark plasma sintering technique was investigated and the related sintering mechanism was clarified in detail. Results indicated that during the heating process, one part of the high energy adsorbed by the composites let Cu melt and fill the gaps inside the composites. Meanwhile, there’s different molten condition about Cu duel to different heating temperature that cause Cu fill in the most space between Ti3SiC2 particles. The other part of the energy caused to the local high temperature, contributing for the chemical reaction and the formation of TiCx and Cu3Si. Therefore, at the same heating rate, the composites showed better mechanical property and higher density with a longer heating time. The heating stage played an important role in the change of the mechanical property, microstructure and volume of the composites. During the holding stage, because the amount of the reactants significantly decreased, the related chemical reaction got slow and the energy needed during this stage was lower than that during the heating stage. And the particle of Ti3SiC2 need more time for moving to the space of Cu. Therefore, the higher the holding temperature, the more significant was the diffusion of the phases. The more uniform the phases, the higher was the density. When heating temperature (higher than holding temperature) cause Cu complete melt and holding temperature keep the Cu in semi-melt, there will be a more effective sintering method.

Influence of sintering on mechanical response of metal injection moulded parts

ABSTRACT Sintering is often the final step during Metal Injection Molding (MIM) and does in an observable way contribute to influencing both the characteristics and performance of final products. In this research paper, the influence of sintering parameters on dimensional stability and mechanical properties of parts having three different shapes is presented and adequately discussed. A CI 90 feedstock having 90 weight percent of Carbonyl Iron powder was prepared by mixing the carbonyl iron powder with an organic binder. The GSGR75 feedstock has 75 weight percent of powder of grinding sludge and graphite. The green samples were subject to thermal debinding at 750°C. The brown samples were sintered at the temperatures of 1100°C, 1200°C, and 1300°C for 60 minutes and in atmospheres of vacuum, argon, and nitrogen. The sintering characteristics of the parts that were produced from the use of the grinding sludge powder (GSGR) were found to be inferior to those produced from the use of the carbonyl iron (CI) powder. This is essentially because of the limited degree of reduction coupled with the presence and distribution of a sizable number of pores. The sintering parameters did exert an influence on the properties of the as-sintered end-product. Distinct empirical relations were developed and verified for the purpose of predicting properties of the sintered product based on the sintering parameters used.

Influence of sintering parameters on the grain growth and mechanical properties of Ti(C,N)-based cermets prepared via mechanical activation and in-situ carbothermal reduction

Series of new type (Ti,Mo)(C,N)-based cermets sintered at different final sintering temperatures were prepared by the mechanical activation and in-situ carbothermal reduction method in vacuum. The grain growth behavior of the complete solid solution cermets was firstly studied by prolonging the holding time at 1400 °C by using XRD, SEM, and TEM. Results indicated that the thermodynamic three-dimensional equilibrium morphology of the hard-phase particles were {111}-faceted and round-edged octahedron, whose growth mechanism were predominated by the two-dimensional nucleation that controlled by the diffusion of the dissolved alloying elements in the binder along the close-packed direction. The microstructure and mechanical properties of the cermets were also studied. The results indicated that either too low or too high sintering temperature could deteriorate the homogeneity and porosity of the cermets. Only when the sintering temperature was 1400 °C, the optimum TRS, hardness, and fracture toughness of the cermets were 2134±30 MPa, 88.0±0.3 HRA, and 20.1±0.3 MPa·m 1/2 , respectively.

Influence of Sintering Parameters on Spectroscopic Properties of BMW: Eu3+ Ceramic Materials Prepared by HPLT Technique.

In this work, Ba2MgWO6: Eu3+ (BMW: Eu3+) ceramic materials with a double perovskite structure were sintered using the High-Pressure Low-Temperature sintering (HPLT) technique. As part of the research, the influence of pressure (CP), sintering temperature (CT), and sintering time (CTS) on the structure and luminescence of the doped BMW were determined. Structural analysis via XRD and SEM + EDS and spectroscopic analysis via emission and excitation spectra, decay time, and absorption spectra of the obtained ceramics were performed. Dense double perovskite ceramics were obtained with a cubic structure with optimal sintering parameters: T = 500 °C, p = 8 GPa, and t = 1 min. The increase in temperature caused an increased extinction of the luminescence due to the diffusion of carbon into the ceramics. The increase in pressure led to the formation of the amorphous phase, which increased the speed of non-radiative transitions and also led to the extinction of the luminescence. The increase in sintering time from 1 to 3 min enhanced the luminescence output, but when the ceramic was sintered for 5 min, the luminescence was quenched, most likely by increasing the rate of the non-radiative process, as evidenced by reduced decay time.

Effect of sintering parameters on the microstructure and micromechanical properties of in-situ synthesized boride phases (Fe2B-FeB) in iron matrix composites reinforced with B4C particles

In this study, the influence of sintering parameters on the microstructure and micromechanical properties of ceramic reinforced iron matrix composites is investigated. Composites containing 5–10-20-30 vol% B 4 C were fabricated by in-situ powder metallurgy (IPM) and sintered at various temperatures and durations. Hot pressed powder mixtures were sintered at constant duration (60 min at 1000–1150-1300 °C) and constant temperature (1150 °C for 30–120 min) in a protective environment. The influence of these parameters is evaluated by investigating microstructural changes using SEM, XRD, EDX, and optical microscopy, density and porosity by Archimedes method, and finally, micromechanical properties by hardness determination. Results showed that while increasing reinforcement ratios of B 4 C particles caused reduced density in the green compacts, B 4 C particles under a certain size (<7 μm) were randomly distributed in the mixture and lead to the formation of iron borides. Additionally, increased hardness was witnessed for all temperatures with increasing reinforcement ratios until 20 vol% B 4 C, after which hardness was decreased. In fact, 20 vol% B 4 C showed excellent properties and was comparatively much sensitive to both, increasing sintering temperatures and duration. In-situ synthesized iron borides became the decisive factor in the increased hardness of the composites. • The properties of Fe-B 4 C composites were evaluated at various sintering parameters. • The iron boride phase was formed in different sizes and shapes as a result of the diffusion of boron from the B 4 C. • Composition of mixture powders and sintering time affected the dispersion of the boride phase. • The hardness of composites was significantly developed by in-situ synthesized boride phases. • Sintering time causes the phase formation in larger areas that enhanced the overall hardness.

Effects of carbon nanotubes and sintering parameters on microstructure and properties of PCD

Polycrystalline diamond (PCD) was sintered from onion-like carbon (OLC) mixed with multi-walled carbon nanotube (MWCNT) at 5.5 GPa/1100–1300 °C/5–20 min holding time, in which OLC was generated by vacuum annealing of nano-diamond. Structures, morphologies, and properties of composites were characterized by X-ray diffraction, field emission scanning electron microscope, high-resolution transmission electron microscopy, and hardness measurement. The purposes of this paper were to lower the temperature of OLC conversion into PCD and optimize the performance of the PCD. The influence of sintering parameters on the microstructure and properties of PCD and the change of MWCNT and OLC structure in high-pressure and high-temperature (HPHT) were studied. Finally, when the mass fraction of carbon nanotubes is 10 %, the optimal process conditions were as follows: sintering pressure 5.5 GPa, temperature 1150 °C, holding time 20 min, sintering hardness was 18.84 GPa, and conversion rate of OLC to diamond was 25.96 %. Under the influence of HPHT and surrounding OLC, the MWCNT tends to be transformed into spheroids, while the structure of the OLC/MWCNT binding zone is graphite. This work not only provided a theoretical basis for the study of carbon nanotubes but also provided reasonable parameters for the synthesis of PCD.

Fabrication of spark plasma sintered porous Ti-6Al-4V using PCA-added space holder method for bone implant materials

Ti-6Al-4V alloy has been used for bone implant materials. The porous Ti-6Al-4V lowers the mechanical misfit and prevents the implant loosening between bone and metal implant. The influence of sintering parameters, i.e., heating rate, sintering temperature, pressure, space holder size, and its distribution to the formation of both micro and macro- porosity is investigated. The initially developed image analysis of samples was used to quantitatively analyze the influence of process control agent (PCA) on the distribution of macro-pores. From the SEM results and samples relative density, it is found that the main parameter to control in the solid-state space holder method is space holder distribution, sintering pressure, and sintering temperature. Additionally, the most effective condition to produce less micro-porosity and more interconnectivity between macro-pore is the utilization of 10 wt% ethanol as PCA and sintering at 700 °C, 60 MPa.

3D ink-printed, sintered porous silicon scaffolds for battery applications

The fabrication of 3D ink-printed and sintered porous Si scaffolds as electrode material for lithium-ion batteries is explored. A hierarchically-porous architecture consisting of channels (~220 μm in diameter) between microporous Si struts is created to accommodate the large volume change from Si (de)lithiation during electrochemical (dis)charging. The influence of sintering parameters on Si strut porosity and the resulting mechanical and electrochemical properties of the scaffolds are studied experimentally and computationally. Varying sintering temperatures (1150–1300 °C) and sintering times (1–16 h) the open porosity within the Si filaments can be tailored between 46 and 60%. Pore size (3–6 μm) and wall thickness (3–8 μm) can be adjusted to tailor the surface-to-volume ratio. Computational results show that maximum capacity is expected at ~50% Si strut porosity, balancing short diffusion lengths and sufficient volume of active material. Stress concentrations are reduced at higher filament porosities albeit at the cost of energy density. For a filament porosity of 46%, hierarchically porous Si microlattice electrodes display gravimetric and volumetric capacities as high as 2,990 mA h g −1 and 2,860 mA h cm −3 , respectively. The simple 3D printing + sintering approach provides further opportunities for optimization of Si electrodes by geometrical freedom. • Si-powder inks are 3D ink printed into micro-scaffolds used as electrodes. • Partial sintering of Si yields hierarchical porosity within the scaffold struts. • Porosity accommodates the immense Si volume changes upon (dis)charging. • A primary battery with up to 2,990 mA h g-1 is demonstrated.

Statistical modelling of mechanical properties and bio-corrosion behaviour of Mg3Zn1Ca15Nb fabricated using microwave sintering

In the present work, an optimum set of microwave sintering parameters was used to fabricate a newly developed biomaterial, namely Mg3Zn1Ca15Nb, with improved mechanical and bio-corrosion properties. In the recent work by authors, sintering parameters were optimized using the conventional sintering route (R1) to sinter Mg3Zn1Ca15Nb, which resulted in improved mechanical and degradation properties. Subsequently, to achieve better properties of Mg3Zn1Ca15Nb over R1, a microwave sintering route (R2) was used to sinter the same material at similar parameters, which were used in R1. However, the obtained properties of magnesium alloy matrix composite (MgMCs) sintered using R2 were found to be lower than the R1. This article was aimed to optimize the sintering parameters by microwave sintering route (R3) to get significant results over R1. Sintering parameters such as heating rate, sintering temperature, and holding time were taken for optimization. Also, the influence of sintering parameters on the mechanical and bio-corrosion properties of MgMCs was studied. Experimentations were proceeded according to central composite design (CCD). The mechanical and bio-corrosion properties of Mg3Zn1Ca15Nb, sintered using R3 was better than the R2. However, these properties were still behind the properties of the sample sintered using R1. Scanning electron microscopy (SEM) images of the sample showed clustering of powders and micro-cracks on the surface of the sample sintered using R2. However, by increasing the heating rate, a reduction in powder clustering and micro-cracks were observed. Additionally, the microscopic image showed a reduction in the size of porosity with an increase in heating rate. No phase formation was observed in the microwave sintered samples as per X-ray diffraction (XRD) analysis. In addition to this, the hydrophilic nature of Mg3Zn1Ca15Nb showed a good agreement for cell adhesion. Subsequently, the bio-corrosion behaviour of fabricated samples was tested in simulated body fluid (SBF) containing pH 7.4 at 37±0.5 °C. The obtained corrosion rate of sample sintered using R3 was less than R2, whereas it was still higher than R1.

Fabrication of high magnetic performance Fe–50Ni alloy by powder injection molding

ABSTRACT Fe–50Ni alloy is widely used for soft magnetic applications due to attractive magnetic properties. In this study, Fe–50Ni soft magnetic alloy was produced by powder injection molding. The influence of sintering parameters was investigated on the density, grain size, and magnetic properties. The injected parts were sintered at 1300–1375°C for 2–14 h with subsequent controlled slow cooling. It has found that permeability and magnetic induction improved with increasing sintering time and temperature, whereas the coercivity was reduced significantly. The sintered density and grain size of 98% and 240 µm were obtained in this study. Consequently, excellent magnetic properties of Fe–50Ni were achieved. The values of magnetic permeability and saturation induction were 50,240 and 1.52 T, respectively.

Fabrication of Paper‐Derived Ti3SiC2‐Based Materials by Spark Plasma Sintering

Novel paper‐derived Ti3SiC2‐based ceramics are fabricated by spark plasma sintering (SPS). A Ti3SiC2‐loaded preceramic article is used as feedstock. The sintering temperature and pressure are 1100–1200 °C and 20–50 MPa, respectively. The influence of sintering parameters on phase composition and microstructure is analyzed by X‐ray diffraction (XRD) and scanning electron microscopy, respectively. In addition, energy‐dispersive X‐ray spectroscopy is conducted to analyze the distribution of elements and the phase arrangement depending on the sintering temperature. XRD analysis of the composites sintered at 1100 and 1200 °C shows the presence of Ti3SiC2, TiC, and TiSi2 phases while the content of Ti3SiC2 phase decreases with increasing temperature. It is shown that an increase in both temperature and pressure lead to higher densification of the composites. Elongated pores are observed in the composites, which are formed as a result of cellulose fiber decomposition during the sintering process. The maximal value of the flexural strength of 300 MPa is measured for the composite with the highest density. The influence of SPS parameters on the formation of phase composition, microstructure, and mechanical properties of the paper‐derived Ti3SiC2‐based ceramics is discussed.

SiC- and Ti3SiC2-Based Ceramics Synthesis by Spark Plasma Sintering of Preceramic Paper

This paper is devoted to proposing a new approach to the synthesis of SiC- and Ti3SiC2-based ceramics by using of preceramic paper as a feedstock. A preceramic paper with SiC and Ti3SiC2 powder fillers were sintered by spark plasma sintering (SPS) method for holding time 10 minutes under pressure 20-100 MPa. The temperature for the sintering of SiC- and Ti3SiC2-filled paper was 2073-2373 K and 1373-1473 K respectively. The influence of sintering parameters on the materials microstructure was analyzed by scanning electron microscopy. It was revealed that with an increase in pressure from 20 to 100 MPa, the microstructure of the materials becomes denser. It agrees with the results of measuring the density of the sintering materials by the hydrostatic weighting. The determination of Young`s modulus by the acoustic method demonstrates that with the increase of the applied pressure during SPS, Young’s modulus of the synthesized SiC- and Ti3SiC2-ceramics increase.

High‐Pressure Sintering of Rhombohedral Cr2S3 Using Titanium–Zirconium–Molybdenum Tools

The influence of sintering parameters on the physical properties and the chemical structure of rhombohedral Cr2S3 (rh‐Cr2S3) is investigated using high pressures and high temperatures. The densification of the powder is performed by applying the high‐pressure field‐assisted sintering technique/spark plasma sintering. Using a titanium–zirconium–molybdenum (TZM) alloy as sintering tool, it is possible to increase the magnitude of the applied pressure to several hundred MPa at temperatures as high as 1223 K. A relative density of up to 99.9% is achieved at a sintering temperature of 1223 K and a pressure of 395 MPa. The presence of phase‐pure rh‐Cr2S3 is proven by X‐ray diffraction analysis and transmission electron microscopy. The Seebeck coefficients of the self‐doped samples change drastically with the sintering temperatures ranging between −650 and −350 μV K−1. The densities and the thermal conductivities of the sintered samples increase with increasing sintering temperatures. The electrical conductivity is largely increased compared with the thermal conductivity potentially due to the current‐assisted high‐pressure sintering.

Influences of sintering parameters on shape-retention ability of porous Ni3Al intermetallic fabricated by powder metallurgy

Porous Ni3Al intermetallic is successfully fabricated through elemental powder metallurgy of Ni-25 at% Al samples. The influences of sintering parameters, such as heating rate, isothermal treatment on the sintering behaviors of the samples are investigated. When the samples are heated continuously from room temperature to 1000 °C at a relatively high rate (>5 °C/min), the reaction between Ni and Al happens in an intense way. The heat suddenly released by the reaction produces liquid phase in the material, which facilitates the reaction significantly. Therefore, a sudden expansion (∼6%) occurs, resulting in severe deformation of the samples. The shape retention ability of the sample can be improved by isothermally treating the sample at a proper temperature (470–490 °C) for prolonged time or heating it up at a low heating rate. Under these sintering conditions, the reaction between Ni and Al happens in a much more controllable solid-state way. Therefore, the abrupt expansion can be decreased to ∼0.5%. During the solid-state reaction, imbalanced diffusion between Al and Ni results in more Al diffusing into Ni than the other way around, therefore creating pores on the Al side. As a result, homogeneous porous Ni3Al intermetallic samples can be fabricated and the regular shape of the sample can be well preserved.

Fuzzy Logic Model System for Prediction of Process Parameters by Plasma Assisted Diffusion Bonding of Dissimilar Alloys

In this study, dissimilar materials such as commercially pure titanium and austenitic stainless steel (304 L grade) was diffusion bonded using plasma assisted sintering process. The generic approach of response surface methodology based central composite design was employed to perform the experiments. The influences of sintering parameters viz., bonding temperature (T), applied pressure (P) and holding time (t) on the quality and performance characteristics of specimens are merely non-linear in nature. Therefore, the rule-based fuzzy logic intelligent modelling was employed to predict the shear strength and interface hardness of bonded specimens. It is evident that the developed fuzzy logic model is greatly comparable with the experimental results. The result of the study shows the adequacy of the developed fuzzy logic approach for the effective prediction of the responses in diffusion bonding process.

The Influence of Sintering Parameters in the Microstructure and Mechanical Properties of a Cu–Al–Ni–Mn–Zr Shape Memory Alloy

Shape memory alloys from the Cu–Al–Ni system arouse interest for industrial applications due to their high thermal stability and low cost. In this study, the Cu–11.8Al–3.2Ni–3Mn–0.5Zr alloy is prepared through a powder metallurgy processing technique. Specimens are produced by a conventional uniaxial press followed by sintering procedure under argon atmosphere. The sintering temperature is varied in the range from 950 to 1060 °C, whereas sintering time is varied from 0.5 to 2 h. The results denote that a temperature close to the alloy's solidus temperature is necessary to achieve higher densities. Moreover, martensite‐type microstructures are observed, despite the slow cooling rate applied after sintering. The compression strengths are in the order of 500 MPa with the exception of the specimens sintered for 1.5 h, which reaches an average of 700 MPa. This is explained by the lower porosity resulting from liquid phase sintering. The forward and reverse martensitic transformation temperatures, however, are quite similar for all examined conditions.

Transparent Polycrystalline Magnesium Aluminate Spinel Fabricated by Spark Plasma Sintering.

Polycrystalline magnesium aluminate (MgAl2 O4 ) spinel (PMAS) exhibits a unique combination of physical, chemical, mechanical, and optical properties, which makes it useful for a wide range of applications, including UV lenses for lithography, electroinsulation, and structural windows for both VIS and IR region radiation and armor applications. Conventional two-stage processing of PMAS involves prolonged pressureless sintering followed by hot isostatic pressing. The costly processing of high-quality transparent PMAS ceramic is the main reason for the limited usage of this material in industry. Spark plasma sintering (SPS) is a relatively novel one-stage, rapid, and cost-effective sintering technique, which holds great potential for producing high-quality optical materials. Here, recent advances in the fabrication of transparent PMAS by the SPS approach, the influence of sintering parameters on microstructure evolution during densification, and their effects on the optical and mechanical properties of the material are reviewed.