Powder Heat Research Articles

Synthesis of hydroxyapatite from Faunus ater shell biowaste

The current research involved the synthesis of hydroxyapatite powders using Faunus ater shell (FaS), which is a snail found in brackish water, as a source of calcium. Hydroxyapatite (HAp) is produced through the hydrothermal synthesis of FaS, employing calcination temperatures at 900 °C (HAp900) and 1000 °C (HAp1000). The samples underwent analysis through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) to determine the phases present. Additionally, quantitative chemical analysis of the synthesized and heat-treated powders was conducted using X-ray fluorescence (XRF) spectroscopy. XRD analysis determined that HAp900 and HAp1000 exhibited amorphous structures, with the additional presence of Tetracalcium Phosphate (TTCP) phase detected in HAp 900. Furthermore, XRF analysis was conducted on both samples, revealing molar ratios of Ca/P as 2.56 and 1.67 for HAp900 and HAp1000 respectively. The FTIR spectrum revealed that the synthesized HAp contains phosphate, carbonate, and hydroxyl groups.

Effect of heat treatment on the gas-atomized nickel‑aluminum bronze feedstock powders for cold spray

Due to the high strength of the nickel‑aluminum bronze (NAB), the cold spray deposition efficiency of the NAB powders was less than satisfactory. To improve the deformation behavior of powder, different heat treatment strategies were adopted for gas atomized NAB powders and then the heat-treated powders were deposited on NAB substrates using a high-pressure cold spray system. For various powders and their corresponding deposits, a series of related characterizations were performed. The results indicate that the microstructure of the gas-atomized powder was mainly composed of martensitic β′ and bainite α with high hardness, resulting in low deposition efficiency and poor bonding between particles and particles in the prepared deposits. An effective technique of heat treatment can eliminate the non-equilibrium structure in the gas atomized powder, reduce the hardness of the powder, and significantly improve the deposition efficiency and enhance particle interface bonding.

Processing, Microstructure, and Properties of Bimetallic Steel-Ni Alloy Powder HIP

This work explores technical feasibility in hot isostatic pressing (HIP) manufacturing of an integral bimetallic component using steel and Ni alloy powder for supercritical carbon dioxide (sCO2) turbomachinery. Lab-scale bimetallic HIP specimens using HAYNES® 282® and SS316L or SS415 powder are investigated in powder configuration, heat treatment, microstructure, and tensile properties up to 400 °C. Interdiffusion profiles at dissimilar alloy interfaces caused by HIP cycle is predicted by DICTRA simulations and validated by electron probe microanalysis (EPMA). The interdiffusion distance of most elements is around 100 μm, while C and N have a higher interdiffusion distance. Dense distribution of Ti-rich carbonitrides and alumina particles are found to decorate prior particle boundaries near joining interface on the 282 side, affecting tensile strength across interface as well as tensile failure location. A higher amount of excessive carbonitride formation near interface is observed in SS316L/282 than in SS415/282, which is consistent with the predicted greater degree of interdiffusion effect in SS316L/282. Typical HAYNES® 282® heat treatment condition is applicable to 282/SS316L and 282/SS415 combinations, resulting in a higher strength than cast CF8M and CA6NM. A pilot-scale bimetallic SS415/282 pipe is then demonstrated to show the promise of scaleup.

Simulating selected magnetic properties of Tb x Pr1− x Al2, a magnetocaloric compound

Tb x Pr1−x Al2 are ferrimagnetic materials exhibiting magnetocaloric effect that have gained considerable attention due to their potential use as an alternative in refrigeration, magnetic sensors and in information storage technology. Here using the mean field approach numerical simulations were conducted for x = 0.1, 0.2, 0.3, 0.4, 0.5, and 0.75, to analyze selected physical properties, such as x-ray and neutron powder diffraction, magnetization and heat capacity. The simulations successfully reproduced the experimental data providing a comprehensive characterization and improved understanding of this family of compound.

Investigating the effect of elevated temperatures on the utilization of demolished paving block powders as supplementary cementitious materials

The study investigated the effects of construction waste powders exposed to elevated temperatures on the properties of cement mortar. The waste powders were obtained from demolished granite and clay blocks after more than 15 years of their service life. The exposure temperatures were 200 °C, 400 °C, 600 °C, and 800 °C. The heat-treated and untreated waste powders replaced cement in mortars at 10% and 20% by weight. The use of untreated recycled granite and clay powders adversely affected the mechanical strength and transport properties of the cementitious mixtures. On the other hand, the effects of thermal exposure varied for the two powder materials. As the exposure temperature increased, the performance of mixtures containing granite powder gradually deteriorated, while mixtures containing clay powder improved. The efficiency was both worst and best at 800 °C. For instance, a mixture containing 10% clay powder treated at 800 °C exhibited compressive strength equivalent to the reference mortar with no waste material. In contrast, under the same conditions, the compressive strength of the mixture containing granite powder was 33% lower. These results indicate that identifying the type and characteristics of recycled materials is essential for their utilization and application of enhancement methodsThe study investigated the effects of construction waste powders exposed to elevated temperatures on the properties of cement mortar. The waste powders were obtained from demolished granite and clay blocks after more than 15 years of their service life. The exposure temperatures were 200 °C, 400 °C, 600 °C, and 800 °C. The heat-treated and untreated waste powders replaced cement in mortars at 10% and 20% by weight. The use of untreated recycled granite and clay powders adversely affected the mechanical strength and transport properties of the cementitious mixtures. On the other hand, the effects of thermal exposure varied for the two powder materials. As the exposure temperature increased, the performance of mixtures containing granite powder gradually deteriorated, while mixtures containing clay powder improved. The efficiency was both worst and best at 800 °C. For instance, a mixture containing 10% clay powder treated at 800 °C exhibited compressive strength equivalent to the reference mortar with no waste material. In contrast, under the same conditions, the compressive strength of the mixture containing granite powder was 33% lower. These results indicate that identifying the type and characteristics of recycled materials is essential for their utilization and application of enhancement methods.

Microwave absorption properties of PDCs-SiC(N) based on heat treatment at different temperatures

Polymer-derived ceramics (PDCs) exhibit diverse microstructures and varying levels of free carbon after pyrolysis at different temperatures, resulting in distinct wave-absorbing capabilities. In this study, PCS, PSN1, and PSN2 with different free carbon concentrations were subjected to heat treatment, followed by systematic characterization of their microstructures, particularly the transformation process of free carbon. Subsequently, the dielectric constants and microwave-absorbing properties of the heat-treated PDC powders within the 2–18 GHz range were determined using the coaxial method. Finally, an analysis was conducted on the relationship between loss mechanisms and microstructure in PDCs to establish a foundation for preparing broadband wave-absorbing ceramic matrix composites.

The effect of powder feedstock and heat treatment on the thermal and mechanical properties of binder jet printed ZrC

Zirconium carbide (ZrC) disks were fabricated using binder jet printing to study the effect of powder feedstock, print parameters, and heat treatment on flowability and final materials properties. A median volumetric particle size smaller than 10 μm was shown to cause the powder to stop flowing during printing. Disks were printed using ZrC with suitable flowability and then heat-treated at temperatures between 1800 °C and 2200 °C for 1 or 5 h. The density, part shrinkage, thermal diffusivity, and fracture strength all increased with increasing temperature and time. The heat-treated disks were then heated to 2200 °C for 5 h and the properties converged for disks of the same particle size, indicating the hottest temperature and longest time of exposure dictates the final properties. Lastly, it was shown that larger particles produce lower density materials with worse thermal diffusivity, most likely because of poor connectivity between particles after heat treatment.

Endodontic Radiopacifying Application of Barium Titanate Prepared through a Combination of Mechanical Milling and Heat Treatment

Mineral trioxide aggregates (MTA) are commonly used as endodontic filling materials but suffer from a long setting time and tooth discoloration. In the present study, the feasibility of using barium titanate (BTO) for discoloration and a calcium chloride (CaCl2) solution to shorten the setting time was investigated. BTO powder was prepared using high-energy ball milling for 3 h, followed by sintering at 700–1300 °C for 2 h. X-ray diffraction was used to examine the crystallinity and crystalline size of the as-milled and heat-treated powders. MTA-like cements were then prepared using 20–40 wt.% BTO as a radiopacifier and solidified using a 0–30% CaCl2 solution. The corresponding radiopacity, diametral tensile strength (DTS), initial and final setting times, and discoloration performance were examined. The experimental results showed that for the BTO powder prepared using a combination of mechanical milling and heat treatment, the crystallinity and crystalline size increased with the increasing sintering temperature. The BTO sintered at 1300 °C (i.e., BTO-13) exhibited the best radiopacity and DTS. The MTA-like cement supplemented with 30% BTO-13 and solidified with a 10% CaCl2 solution exhibited a radiopacity of 3.68 ± 0.24 mmAl and a DTS of 2.54 ± 0.28 MPa, respectively. In the accelerated discoloration examination using UV irradiation, the color difference was less than 1.6 and significantly lower than the clinically perceptible level (3.7). This novel MTA exhibiting a superior color stability, shortened setting time, and excellent biocompatibility has potential for use in endodontic applications.

Rats chasing the dragon: A new heroin inhalation method

BackgroundDespite extensive human use of inhalation for ingesting opioids, models in rodents have mostly been limited to parenteral injection and oral dosing. Methods using electronic drug delivery systems (EDDS; “e-cigarettes”) have shown efficacy in rodent models but these do not faithfully mimic the most popular human inhalation method of heating heroin to the point of vaporization. New methodMiddle aged rats were exposed to vapor created by direct heating of heroin HCl powder in a ceramic e-cigarette type atomizer. Efficacy was determined with a warm water tail withdrawal nociception assay, rectal temperature and self-administration. ResultsTen minutes of inhalation of vaporized heroin slowed response latency in a warm water tail withdrawal assay and increased rectal temperature in male rats, in a dose-dependent manner. Similar antinociceptive effects in female rats were attenuated by the opioid antagonist naloxone (1.0 mg/kg, s.c.). Female rats made operant responses for heroin vapor in 15-minute sessions, increased their response rate when the reinforcement ratio increased from FR1 to FR5, and further increased their responding when vapor delivery was omitted. Anti-nociceptive effects of self-administered volatilized heroin were of a similar magnitude as those produced by the 10-minute non-contingent exposure. Comparison with existing methodsInhalation of directly volatilized heroin successfully produces heroin-typical effects, comparable to EDDS inhalation delivery. ConclusionsThis study shows that “chasing the dragon” methods of inhalation of heroin can be modeled successfully in the rat. Inhalation techniques may be particularly useful for longer term studies deep into the middle age of rats.

Achieving high thermal conductivity of Al–50Si alloy through heat treatment and its microstructural evolution

Al–50Si alloys were prepared by powder extrusion and characterized for electronic packaging. The optimization of powder size, extrusion temperature, and heat treatment parameters was performed to enhance the microstructure and thermo-physical properties. The alloy exhibits a high relative density >99 %, a low coefficient of thermal expansion (CTE) < 10 × 10−6/K, and a good thermal conductivity (TC) ∼117 Wm−1K−1 achieved by employing a large size powder and high extrusion temperature during the extrusion process. Subsequent heat treatment of the optimized alloy at 550 °C for various time reveals a fluctuating increasing trend in TC during the heat treatment process. The TC values exhibit periodic fluctuations as they alternate between increments and decrements, primarily resulting from the recrystallization and secondary recrystallization of Al grains during heat treatment process. Notably, the maximum TC value (∼159.1 Wm−1K−1) at room temperature is obtained after heating the alloy to 550 °C for 26 h. Compared to the as-extruded alloy, the TC of heat-treated alloy increases by approximately 36 %, which can be attributed to the elimination of eutectic Si and growth of Si and Al grains within the alloy. The study may shed light on the mechanism underlying the improvement in thermal conductivity of Al–50Si alloy by microstructural evolution.

Effects of powder surface conditions on the rheological behavior of Ti–6Al–4 V alloy powders for additive manufacturing

Laser powder-bed fusion (L-PBF) is a promising manufacturing process for fabricating metallic parts with tailored architectures. A feedstock powder with good flowability is required to homogeneously deposit the powder on the building substrate and obtain reliable and high-quality L-PBF products. Although the effects of powder morphology and particle size on flowability have been widely investigated, the relationship between powder surface conditions and rheological behaviors is not well established. Therefore, in this study, the surface conditions of Ti–6Al–4 V alloy powders were intentionally adjusted through conventional heat treatments under different gas atmospheres. The morphology and particle size distribution of the Ti–6Al–4 V powder heat treated at 773 K in air (Air773) and Ar (Ar773) atmospheres remained unchanged compared to those of the untreated powder. However, the quantity of surface oxides on the Air773 powder increased, enhancing the decoration of surface hydroxyl groups, as illustrated by water wettability tests. By contrast, the oxide layer of the Ar773 powder decomposed and dissolved into the matrix, resulting in the generation of fresh metallic surfaces. Consequently, the flowability of the Air773 powder increased, whereas that of the Ar773 powder tended to decrease, thereby deteriorating the quality of powder beds during the recoating process. The results prove that the cohesive strength of Ti–6Al–4 V powder is more strongly determined by metallic TiTi interactions than by hydrogen bonds. Thus, the effective approach for adjusting the powder surface conditions presented in this study offers new insights into the potential for economically developing high-performance Ti alloy components by controlling the powder properties and L-PBF process.

Magnetic field-induced phase transitions in Cu(en)2SO4 – A dimerized S = 1/2 quantum antiferromagnet

Magnetic susceptibility, magnetization and specific heat of powder and single crystal of Cu(en)2SO4 were investigated. The analysis of the data confirmed that Cu(en)2SO4 can be treated as a quasi-two-dimensional array of magnetic dimers with singlet-ground state persisting up to about 6.5 T. Magnetization and susceptibility studies were performed in the singlet phase and the analysis revealed that g-factor anisotropy is the main mechanism responsible for the different behavior in the magnetic field applied along the b and c axis. The investigation of powder and single crystal specific heat in magnetic fields applied along all three crystallographic directions revealed only small anisotropy associated with the g-factor anisotropy. All mentioned data sets resemble main features of the spin 1/2 HAF dimer model with J/kB = -5.52 K. The observed deviations can be ascribed to the presence of inter-dimer interactions with the effective strength z’J’/kB = -2.7 K. In fields above 6.5 T the system passes from the singlet phase to the ordered state stable up to about 11 T. The expectation of a dome shape magnetic phase diagram is based on the strong dimerization of the magnetic lattice. Future experiments and calculations are discussed to identify the origin of the quantum phase transition associated with the gap closing.

Unravelling the Influence of Composition and Heat Treatment on Key Characteristics of Dairy Protein Powders Using a Multifactorial Approach.

The purpose of this study was to improve understanding of the structural and functional property changes that milk-protein concentrates undergo during production, particularly how the manufacturing route (heat treatment position and intensity), standardization (in osmosed water or ultrafiltrate permeate) and formulation (casein:whey protein (Cas:WP) ratio) influence the physico-chemical characteristics-hygroscopicity, particle size, sphericity, density and evolution of browning during storage. To obtain a comprehensive understanding of the parameters responsible for the distinctive characteristics of different powders, a multifactorial approach was adopted. Hygroscopicity depended mainly on the standardizing solution and to a lesser extent the Cas:WP ratio. The particle size of the heat-treated casein-dominant powders was up to 5 μm higher than for those that had had no heat treatment regardless of the standardizing solution, which also had no influence on the sphericity of the powder particles. The density of the powders increased up to 800 kg·m-3 with a reduced proportion of casein, and lactose and whey proteins participated in browning reactions during storage at 13 °C. In increasing order, the modality of heat treatment, the standardizing solution and the Cas:WP protein ratio influenced the key characteristics. This work is relevant for industrial applications to increase control over the functionalities of powdered products.

The Effect of Treatment of Powder Precursor on the Properties of Compacted Mg-4Y-3Re Alloy

Abstract Powder metallurgy products display superior performance compared to traditionally cast ingots. The final properties of these products can be altered through various methods, such as pre-treatment of the powder. This study focuses on different pre-treatment techniques, including milling, chemical treatment, and heat treatment, as well as their combinations. The results show that distinct microstructures were produced, and their impact on mechanical and corrosion properties was evaluated. The results indicate that milling and chemical treatment increase the yield strength of the material by up to 34 MPa but decrease the elongation by up to 5%. On the other hand, heat treatment increases the elongation by up to 7% but decreases the yield strength by up to 36 MPa. Corrosion resistance is improved especially by chemical and heat treatment of powders, where the corrosion rate was observed to decrease by up to 50% in comparison to the value of product from atomized powder. Additionally, all types of powder pre-treatment were found to improve the corrosion resistance of the final product. This provides an opportunity to tailor the mechanical and corrosion properties of these materials to meet specific applications.

A dual-solver CFD model for conjugate heat transfer in continuous thermal processing

High temperature heat treatment of powders is a common operation in the manufacturing of a range of commercial products. Often, powders are heated or cooled in discrete quantities while being conveyed through a continuous furnace or oven, where a certain temperature–time profile is required for product quality reasons. For powders that are contained and conveyed in oven-ware (saggars), heat-transfer occurs between the surrounding gas phase and the powder material and oven-ware, as well as between oven ware that is vertically stacked.The large physical size and long transit times through typical industrial furnaces (up to 40 m length) means that a full transient CFD solution for both gas and solid phases is computationally very expensive . In this study, a novel CFD simulation model is developed for conjugate heat transfer in the cooling section at the outlet of a continuous furnace. A particular novel feature in this model is the inclusion of heat conduction in multiple solid domains. A dual-solver approach enables the convective and radiant heat-transfer processes in the gas phase are modelled using a steady-state conjugate solver, while the heat conduction processes within the powders and saggars are modelled using a time-dependent conjugate solver that solves for heat conduction only. Using only steady-state solution for the gas phase enables a “snap-shot” of the thermal performance of the system to be generated in a reasonable time frame, which has practical implications for modelling of large-scale industrial equipment. In the “dual-solver” approach, heat fluxes at solid boundaries from the steady-state model are applied as boundary conditions to the transient solver, while the temperature field resulting from the solution of the transient solver is then applied to the steady-state model. Radiative cooling effects are accounted for using a discrete-ordinates model.

A practical method to improve mechanical and electrical properties of ADS copper prepared by cold spray additive manufacturing through powder pretreatment

To reduce the oxygen content on the surface of alumina dispersion-strengthened copper alloy powders, and improve properties of the deposits prepared by cold spray additive manufacturing, these powders were pretreated with hydrogen reduction treatment at 300 ℃ and 500 ℃, respectively. The microstructure and mechanical and electrical properties of the deposits before and after powder heat treatment were systematically researched. The results show that hydrogen reduction treatment can effectively reduce the oxide film on the surface of the alumina-dispersion-strengthened copper powder without changing the microstructure and mechanical properties of the powder. The alumina-dispersion-strengthened copper alloy deposit prepared from the as-received powder has obvious pores, and the tensile strength and electrical conductivity are 75 MPa and 38% IACS, while these deposits prepared from the powder treated at 300 ℃ and 500 ℃ present a dense microstructure. The tensile strengths and electrical conductivity are 202 MPa under 45% IACS and 245 MPa under 48% IACS, respectively. At the same time, the nano-Al2O3 particles are very stable under the heating and deformation conditions of adiabatic shearing by cold spraying, and the Al2O3 particles are not significantly broken during the severe plastic deformation caused by the high-speed impact of cold spraying, which enables the deposits to directly inherit the nano-dispersion strengthening structure of the powder. Therefore, it is effective to improve the mechanical and electrical properties of alumina dispersion-strengthened copper deposits by using hydrogen reduction pre-treatment to reduce the oxide film on the surfaces of the particles.

Nutritional evaluation of heat-treated and raw leaf powder of medicago sativa for freshwater fish, Cirrhinus Mrigala

Nutritional evaluation of heat-treated and raw leaf powder of medicago sativa for freshwater fish, Cirrhinus Mrigala

SIFAT FISIK DAN SENSORIS BUBUK ASAM JAWA YANG DIPRODUKSI MENGGUNAKAN BAHAN PENGISI PATI SINGKONG GAJAH DENGAN METODE FOAM-MAT DRYING

Powder is a processed food product in the form of a fine powder, easily soluble in water, has a long shelf life and is practical. The problem that often arises in tamarind is that it has to separate the seeds and meat so that it is processed into powder. The purpose of this study was to determine the effect of adding filler concentration and foam-mat drying method on physical and sensory properties. This study is an experimental study of factorial RAL with 2 treatments and 3 replications. The first factor is the use of foam-mat drying method and without foaming, the second factor is the concentration of elephant cassava starch filler (10%, 15%, 20% and 25%). The data were analyzed using two way ANOVA and further tested using the Tukey test =5%. The results showed that the addition of cassava starch concentration as a filler and foam-mat drying method had a significant effect on water content, solubility, speed of dissolution by heating, precipitate, color test and sensory properties of tamarind powder.

Microstructural Characterization and Prior Particle Boundary (PPB) of PM Nickel-Based Superalloys by Spark Plasma Sintering (SPS).

This research investigates the microstructure and defects of powder metallurgy (PM) nickel-based superalloys prepared by spark plasma sintering (SPS). The densification, microstructural evolution, and precipitate phase evolution processes of FGH96 superalloy after powder heat treatment (PHT) and sintering via SPS are specifically analyzed. Experimental results demonstrate that SPS technology, when applied to sinter at the sub-solidus temperature of the γ' phase, effectively mitigates the formation of a prior particle boundary (PPB). Based on experimental and computational findings, it has been determined that the presence of elemental segregation and Al2O3 oxides on the surface of pre-alloyed powders leads to the preferential precipitation of MC-type carbides and Al2O3 and ZrO2 oxides in the sintering necks during the hot consolidation process, resulting in the formation of PPB. This study contributes to the understanding of microstructural modifications achieved through SPS technology, providing crucial information for optimizing sintering conditions and reducing the widespread occurrence of PPB, ultimately enhancing the material performance of PM nickel-based superalloys.

Magnetic properties of a multicomponent intermetallic compound Tb$_{0.25}$Dy$_{0.25}$Ho$_{0.25}$Er$_{0.25}$Al$_2$

Polycrystalline multicomponent Laves phase rare earth intermetallic compound Tb_{0.25}0.25 Dy_{0.25}0.25Ho_{0.25}0.25Er_{0.25}0.25Al_{2}2 has been synthesized by arc-melting and characterized by powder X-ray diffraction, magnetization and heat capacity measurements. The sample has MgCu_22-type cubic structure (space group Fd-3m) at 300 K. The compound Tb_{0.25}0.25Dy_{0.25}0.25Ho_{0.25}0.25Er_{0.25}0.25 Al_{2}2 orders ferromagnetically at 50 K (T_CC). This value is almost equal to the average of the ferromagnetic ordering temperatures of the individual RAl_22 (R = Tb, Dy, Ho and Er) compounds. Field dependence of magnetization below T_CC indicates soft-ferromagnetic nature. From the magnetization vs field data obtained near T_CC and the temperature dependence of heat capacity, low field magnetocaloric effect has been estimated.