Heating Sintering Research Articles

Effects of heating rate and sintering temperature on the tensile properties of sintered γ-Ti/Al nanoparticle chains

Abstract This paper presents the results of molecular dynamics simulations that were performed to numerically study the laser sintering process and mechanical behavior of γ-Ti/Al bimetallic alloy nanoparticles (NPs). The study systematically investigates the effects of heating rate and sintering temperature on the resultant uniaxial tensile performances of the sintered NPs. A chain model was formed by connecting three pre-equilibrated Ti/Al NPs via necks during solid-state sintering. The solid-state sintered chain samples were heated to 1798 K using four different heating rates (0.04, 0.2, 0.5, and 1.0 K/ps). After high-temperature relaxation of selected sintering temperature cases (e.g., 398 K, 598 K, etc. with a 200 K interval) for 10 ns, the heat sintered chain samples underwent a solidification process with a cooling rate of 0.08 K/ps and maintained at 298 K for an additional 1 ns. The resulting sintered chain products were then subjected to uniaxial tension at a strain rate of 0.0001/ps. The thermodynamic properties and crystallographic deformation were investigated during the sintering and subsequent tension processes. Analysis of the yield strengths obtained from the tension tests revealed a statistically significant correlation between the tensile strength of the sintered NPs and the pre-established sintering temperatures at each temperature. This observation indicates that higher sintering temperatures strengthen the neck connections within the NP-chains, leading to greater tensile strength. The higher sintering temperatures can reinforce the neck during high-temperature relaxation. It is worth noting that the effect of heating rates on mechanical properties was less pronounced when the sintering temperature was constant.

LunaIcy: Exploring Europa’s Icy Surface Microstructure through Multiphysics Simulations

Abstract A multiphysics simulation model incorporating a sintering model coupled with the MultIHeaTS thermal solver was developed to study the evolution of icy moons’ microstructure. The sintering process is highly dependent on temperature, and this study represents the first attempt in planetary science to examine the coupled interaction between heat transfer and sintering. Our approach to ice sintering is based upon the literature while offering a refined description of the matter exchange between grains, bonds, and the pore space. By running the numerical framework, we simulate the evolution of ice microstructure on Galilean satellites, specifically tracking the changes in the ice grain and bond radii over time. LunaIcy, our multiphysics model, was applied to study the evolution of Europa’s ice microstructure over 1 million yr along its orbit, with a parameter exploration to investigate the diverse configurations of the icy surface. Our results indicate that effective sintering can take place in regions where daily temperatures briefly surpass 115 K, even during short intervals of the day. Such sintering could not have been detected without the diurnal thermal coupling of LunaIcy due to the cold daily mean temperature. In these regions, sintering occurs within timescales shorter than Europa’s ice crust age, suggesting that, in present times, their surface is made of an interconnected ice structure.

Light-weight high strength porous thermal insulation materials based on dolomite-granite waste

The first choice for the treatment of solid waste is its industrial utilization. Therefore, in the present study, dolomite tailings and granite waste are used as the basic raw materials, along with silicon carbide as a high-temperature foaming agent, to prepare a light-weight, high-closed porosity thermal insulation material. The effects of (i) the chemical compositions of the main raw materials and (ii) the relationship between the sintering process and the properties, microstructure and crystalline phase of the samples are systematically investigated. At the same time, the formation mechanism of high closed porosity of the thermal insulation material is analyzed. The results showed that when sintering temperature, time, and heating rate are 1200 °C, 30 min, and 3 °C/min, respectly, the sample density, compressive strength, true porosity, and closed porosity are 0.7 g/cm3, 6.62 MPa, 74.21%, and 66.36%, respectively. In addition, due to the high closed porosity, relative to traditional inorganic thermal insulation materials, the water absorption and thermal conductivity are significantly reduced to as little as 1.5%, and 0.30 W/(m·K), respectly. This research not only realizes the recovery and utilization of granite waste and dolomite tailings, but also provides a new prospect for energy saving and consumption reduction in the construction industry.

A Rapid Thermal‐Radiation‐Assisted Sintering Strategy for Nd–Fe–B‐Type Magnets

The green transition has spiked demand for high‐performance sintered Nd–Fe–B permanent magnets, necessitating advanced powder consolidation technologies to enhance production efficiency. This study explores the rapid sintering methodology for an Nd–Fe–B powder using a radiation‐assisted sintering approach. The case study material is an industrially used powder, prepared through strip‐casting, hydrogen decrepitation, and jet milling, with a mean particle size of 5.5 μm. The powder is sintered to full density in a modified spark plasma sintering furnace, achieving pressureless conditions and eliminating electrical currents in the sample to preserve grain alignment and prevent decomposition of the hard‐magnetic phase. Fully dense samples are obtained with heating rates ranging from 10 to 200 °C min−1 and up to 5 min of dwell time at 1100 °C. Rapid heating results in grain size and microstructure comparable to conventionally sintered magnets prepared from the same powder, without compromising magnetic performance after postsinter annealing at 520 °C for 120 min. This sintering method contributes to a novel strategy for optimizing magnet production by utilizing efficient thermal‐radiation heat transfer. The combination of rapid heating and pressureless sintering drastically reduces heat‐up and dwell times, providing a fundamental advantage over slow conventional sintering.

Pulse current enhanced densification and mechanical property of Inconel 718 superalloy fabricated by spark plasma sintering

The Inconel 718 superalloy was fabricated using spark plasma sintering (SPS) technology with varying sintering temperatures and heating rates. The densification and mechanical property of the sintered superalloys were characterized through tensile and compression tests at room temperature, as well as microscopic analyses. The evidence suggests that the plasma generated between the particles results in evaporative melting on the particle surface and plastic deformation of the particle boundaries, accelerating the densification process is by 3∼4 times. Besides, the grain size refinement coefficient affected by pulse current in the holding stage is 0.7–0.8, leading to a significant grain boundary strengthening during SPS process. The dislocation dominated by ball milling and SPS parameters also helps improve the strength and plasticity of the sintered superalloy. The superalloy sintered at 1050 °C with a heating rate of 100 °C/min demonstrated the highest tensile and compressive fracture strengths, measuring 1410 MPa and 1983 MPa, respectively, with the tensile and compressive yield strength of 712 MPa and 1557 MPa, respectively. Lower sintering temperatures or higher heating rates results in lower levels of densification and decreased strength. In addition, plasticity is reduced at higher sintering temperatures or lower heating rates due to excessive precipitation of brittle phases.

Recent Trends and Technologies in rapid prototyping and its Inclination towards Industry 4.0

Prototyping technology is becoming vital in the business as a means of cutting costs and manufacturing time. At present, reverse engineering and rapid prototyping are important technologies that enhance prototype development. The traditional approaches require various intricate processes, such as selective heat sintering (SHS), digital-light-processing printer (DLP), remote distributed rapid prototyping model (RDRP), Stereo Lithography (STL) models, and reconstructing computer-aided design (CAD) models from scanned point data and these approaches has limitations in terms of time-consuming and expert knowledge required for automation. This study aims to explore the significance of Industry 4.0 and its impact on rapid prototyping. The study also addresses rapid prototyping in computer network architecture; digital-light-processing printers (DLP) in rapid prototyping, and software-defined network (SDN) networks in the context of rapid prototyping. Along with this powder bed fusion (PBF) method and electron beam melting (EBM) are included in the manuscript. Based on our exploration, the study suggested vital recommendations for the advancement in rapid prototyping using Industry 4.0

Impact of microwave sintering and NiO additive on the densification and conductivity of BaCe0.2Zr0.7Y0.1O3-δ electrolyte for protonic ceramic fuel cell

This work investigated the influence of microwave sintering on the BaCe0.2Zr0.7Y0.1O3-δ phase, incorporating 2 mol% or 4 mol% NiO as sintering aid. X-ray diffraction analysis of perovskite phase detected a rhombohedral structure under both sintering heating rates (280 and 500 °C/min), also exhibiting the presence of a second phase deficient in Ba with Ni incorporated into the structure, replacing part of the Zr. Raman analysis indicated no distortions in the perovskite structure, independent of the rates and NiO concentrations. The efficacy of NiO addition as a sintering aid was demonstrated by high densification of the samples, exceeding 97 % relative density. Detailed analysis of structural, microstructural, and conductivity properties revealed that microwave sintering, particularly using a heating rate of 500 °C/min, yielded superior results compared to conventional sintering. The enhanced electrical response was attributed to a higher concentration of structural defects, oxygen vacancies, in the microwave-sintered samples, evidenced by the band at 630 cm−1 in the Raman spectrum. Among these, the BCZY sample with 2 mol% NiO, sintered under these conditions, stood out as the most promising, showcasing not only high density but also a uniform microstructure and appreciable electrical conductivity.

The Limited Incorporation and Role of Fluorine in Mn-rich Disordered Rocksalt Cathodes.

Disordered rocksalt oxide (DRX) cathodes are promising candidates for next-generation Co- and Ni-free Li-ion batteries. While fluorine substitution for oxygen has been explored as an avenue to enhance their performance, the amount of fluorine incorporated into the DRX structure is particularly challenging to quantify and impedes our ability to relate fluorination to electrochemical performance. Herein, an experimental-computational method combining 7Li and 19F solid-state nuclear magnetic resonance, and ab initio cluster expansion Monte Carlo simulations, is developed to determine the composition of DRX oxyfluorides. Using this method, the synthesis of Mn- and Ti-containing DRX via standard high temperature sintering and microwave heating is optimized. Further, the upper fluorination limit attainable using each of these two synthesis routes is established for various Mn-rich DRX compounds. A comparison of their electrochemical performance reveals that the capacity and capacity retention mostly depend on the Mn content, while fluorination plays a secondary role.

Investigation of Microstructures and Mechanical Properties of Al2024/6061/7075-Graphene Composites

This work aimed to compare the mechanical properties and microstructures of Al2024-graphene, Al6061-graphene, and Al7075-graphene composites produced via the induction hot pressing and powder metallurgy method. The influences of graphene content (0.15-0.45wt.%), heat treatment (sintering and induction hot-pressing), and matrix material (Al2024, Al6061, and Al7075) on the mechanical strength and microstructure of specimens were studied. Compared to Al2024, Al6061 and Al7075 alloys, the compressive strength of Al2024-0.15graphene, Al6061-0.15graphene and Al7075-0.15graphene composites increased by 33.74%, 24.9% and 32%, respectively. The highest compressive strength (506±5 MPa), hardness (164±1.5 HV), and apparent density (2.65 g/cm3) were achieved in sintered and induction heat-treated Al7075-0.15%graphene composite. As a result, it was determined that graphene is an effective reinforcement element. It has been determined that induction hot-pressing improves the mechanical strength of composite materials.

Flash luminescence, resistive switching and metal-insulator transitions in ceramic oxides

A combination of voltage-induced, reversible OFF-ON resistive switching and electroluminescence is reported in two materials that are both mixed conductors of oxide ions and electron holes. This occurs at high temperatures, 450–700 °C in cubic, fluorite-structured hafnia, YxHf1-xO2-x/2 and at more modest temperatures, 200–300 °C in Ca-doped BiFeO3 with a cubic perovskite structure. In both cases, a small voltage in the range 2–40 V is applied across mm-thick ceramic samples. Both effects are influenced greatly by oxygen exchange with the surrounding atmosphere and involve a combination of electron injection at the cathode, hole injection at the anode and generation of internal pn junctions. There are strong similarities between these effects and flash sintering but without the significant sintering, thermoluminescence and Joule heating that may be observed with flash sintering.

Experimental study and characterisation of 316L stainless steel parts fabricated with metal fused filament fabrication

The 3D printing process of Fused Deposition Modelling (FDM) can be used for fabricating metal parts without the need of mold. Metal Material Extrusion uses metal-polymer composite filament in the 3D printer to extrude the green part, then a de-binding process for removing the polymer binder, and eventually, the sintering process under high temperatures for making a metallic part. A comprehensive research is conducted in which sintering parameters including heating rate, dwell time, and sintering atmospheres are varied for metal parts mechanical characteristics including tensile strength, ductility, and density. Moreover, sintering atmospheres including vacuum and argon are taken into consideration in this research study. The metal part is known as silver part which has exhibited a high mechanical strength of 540 MPa, a considerable density of 7.57 g/cm3, and a high hardness of 220 HV under a vacuum sintering atmosphere. Whereas the metal parts produced under argon atmosphere have shown comparatively low mechanical strength 424 MPa, density 7.1 g/cm3 and 177 HV. The results are compared with an industrial benchmark process where catalytic de-binding and sintering are used to achieve 500 MPa tensile strength, density 7.83 g/cm3, and 175 HV. Scanning Electron Microscopy reveals that grains are coarsened in a vacuum, and grains appear peeled off along with small pores in the boundaries. The industrial benchmark part has uniform and finer grains.

Combined Effect of Particle Reinforcement and T6 Heat Treatment on the Compressive Deformation Behavior of an A357 Aluminum Alloy at Room Temperature and at 350 °C

Solid state sintering of cast aluminum powders by resistance heating sintering (RHS), also known as spark plasma sintering or field-assisted sintering technique, creates a very fine microstructure in the bulk material. This leads to high performance material properties with an improved strength and ductility compared to conventional production routes of the same alloys. In this study, the mechanical behavior of an RHS-sintered age-hardenable A357 (AlSi7Mg0.6) cast alloy and a SiCp/A357 aluminum matrix composite (AMC) was investigated. Aiming for high strength and good wear behavior in tribological applications, the AMC was reinforced with a high particle content (35 vol.%) of a coarse particle fraction (d50 = 21 µm). Afterwards, separated and combined effects of particle reinforcement and heat treatment were studied under compressive load both at room temperature and at 350 °C. At room temperature compression, the strengthening effect of precipitation hardening was about twice as high as that for the particle reinforcement, despite the high particle content. At elevated temperatures, the compressive deformation behavior was characterized by simultaneously occurring temperature-activated recovery, recrystallisation and precipitation processes. The occurrence and interaction of these processes was significantly affected by the initial material condition. Moreover, a rearrangement of the SiC reinforcement particles was detected after hot deformation. This rearrangement lead to a homogenized dispersion of the reinforcement phase without considerable particle fragmentation, which offers the potential for secondary thermo-mechanical processing of highly reinforced AMCs.

Effects of sintering parameters on the preparation and properties of foamed ceramics from cyanide tailings

ABSTRACT In this study, foamed ceramics were successfully prepared using cyanide tailings (CTs) with a high sulfur content as the main raw material. The effects of sintering temperature, holding time, and heating rate on the bulk density, water absorption, porosity, pore structure, and compressive strength of foamed ceramics were systematically investigated. The results showed that the elevated sintering temperature promoted the generation of liquid phases, resulting in an obvious enlargement of the pore size and a decrease in bulk density. In addition, a similar evolution trend could be found in the pore size and bulk density with the extension of the holding time, which was attributed to the degrees of silicon carbide reaction. Foamed ceramics with small pore sizes could be prepared at a heating rate that did not exceed 4°C/min. Then, the higher heating rates could bring abnormally large pores and be detrimental to the mechanical properties of the foamed ceramics, which were proven to be related to the decomposition of FeS2 introduced by CTs during the heating process. In conclusion, the foamed ceramics prepared with CTs in this study provide effective solid waste utilization and have good application prospects in wall composite one-piece insulation panels.

Pilot Tests of Pre-Reduction in Chromium Raw Materials from Donskoy Ore Mining and Processing Plant and Melting of High-Carbon Ferrochromium

Experiments were conducted to pilot the initial reduction in chromium raw materials using the innovative Hoganas technology in a tunnel furnace. To simulate the process, a gas-fired bogie hearth furnace was employed. Technological containers made of silicon carbide crucibles were utilized. Sixteen different combinations of ore and coal mixtures were employed for the initial reduction process. Their total mass was more than 20 tons. Their heat treatment was performed at different temperatures and durations. During the pilot tests, the possibility of achieving chromium metallization was confirmed. Thus, it explains the application of a pre-reduction instead of the sintering or charge heating before the ferrochromium melting, i.e., the power consumption is minimized during the final remelting of the product in DC furnaces. The pilot melting of three batches of the pre-reduced chromium raw materials with various chromium metallization degrees has been tested in the ore-smelting furnace at Zh. Abishev Chemical–Metallurgical Institute (Karaganda). The capacity was 0.2 MVA. To evaluate the technical and economic efficiency of remelting pre-reduced chromium raw materials in commercial DC furnaces, a specific batch of primary ingredients for producing high-carbon ferrochromium, including chromite ore, coke, and quartz flux, was successfully melted in a segregated phase. As a result of the study, it was found that the specific energy consumption for melting high-carbon ferrochromium in the pilot furnace depends on the chromium metallization degree. The researchers tested a range of chromium metallization degrees from 0 to 65% and determined the corresponding specific energy consumption for each degree. Using the data obtained from the study, the researchers were able to assess the melting indexes of high-carbon ferrochromium in a larger 72 MW furnace. They found that by using a pre-reduced product with a chromium metallization degree of 65%, it was possible to reduce the specific energy consumption by half, to around 3.4 MW·h per ton of chromium. Overall, this study highlights the importance of considering the chromium metallization degree when determining the specific energy consumption for melting high-carbon ferrochromium. By optimizing the metallization degree, significant energy savings can be achieved, leading to more efficient and sustainable production processes.

The development of non-resorbable bone allografts: Biological background and clinical perspectives.

Bone grafts are typically categorized into four categories: autografts, allografts, xenografts, and synthetic alloplasts. While it was originally thought that all bone grafts should be slowly resorbed and replaced with native bone over time, accumulating evidence has in fact suggested that the use of nonresorbable xenografts is favored for certain clinical indications. Thus, many clinicians take advantage of the nonresorbable properties/features of xenografts for various clinical indications, such as contour augmentation, sinus grafting, and guided bone regeneration, which are often combined with allografts (e.g., human freeze-dried bone allografts [FDBAs] and human demineralized freeze-dried bone allografts [DFDBAs]). Thus, many clinicians have advocated different 50/50 or 70/30 ratios of allograft/xenograft combination approaches for various grafting procedures. Interestingly, many clinicians believe that one of the main reasons for the nonresorbability or low substitution rates of xenografts has to do with their foreign animal origin. Recent research has indicated that the sintering technique and heating conducted during their processing changes the dissolution rate of hydroxyapatite, leading to a state in which osteoclasts are no longer able to resorb (dissolve) the sintered bone. While many clinicians often combine nonresorbable xenografts with the bone-inducing properties of allografts for a variety of bone augmentation procedures, clinicians are forced to use two separate products owing to their origins (the FDA/CE does not allow the mixture of allografts with xenografts within the same dish/bottle). This has led to significant progress in understanding the dissolution rates of xenografts at various sintering temperature changes, which has since led to the breakthrough development of nonresorbable bone allografts sintered at similar temperatures to nonresorbable xenografts. The advantage of the nonresorbable bone allograft is that they can now be combined with standard allografts to create a single mixture combining the advantages of both allografts and xenografts while allowing the purchase and use of a single product. This review article presents the concept with evidence derived from a 52-week monkey study that demonstrated little to no resorption along with invitro data supporting this novel technology as a "next-generation" biomaterial with optimized bone grafting material properties.

Li8P2S9 solid electrolyte with high ionic conductivity and air stability by Bi2Se3 co-doping

Excellent ionic conductivity and electronic insulation are core properties of solid electrolytes. In this study, we use high-energy ball milling and high-temperature sintering heat treatment to prepare a solid electrolyte, and its ionic conductivity (1.57 × 10−4 S⋅cm−1) is comparable with that of Li8P2S9 in the glass–ceramic state. On this basis, we modify the prepared LPS solid-state electrolyte through Bi2Se3 doping. First-principles computations based on density functional theory (DFT) indicate that Bi2Se3 doping can broaden lithium-ion transport channels and increase the lithium-ion conduction rate. With a doping ratio of 4 %, the ion conductivity reaches 3.02 × 10−3 S⋅cm−1, which offers good insulation to electrons and a stable −0.5 to 5 V (vs. Li/Li+) high-voltage platform. Additionally, Bi2Se3 doping significantly improved the air stability of the LPS solid electrolyte, reducing its adsorption energy to water and preventing the replacement of S by O from H2O.

FEM Analysis on Thermo-mechanical behavior and experimental validation of Al20Cr20Fe25Ni25Mn10 High Entropy Alloy during Spark Plasma Sintering

High entropy alloy developed with spark plasma sintering was modelled with COMSOL Multiphysics. This focus at examining the effect of spark plasma sintering fabrication parameters on thermal and mechanical stress distribution in the sintered Al20Cr20Fe25Ni25Mn10 high entropy alloy (HEA). And to achieve this, a fully thermal-electrical-mechanical integrated and dynamic finite element model (FEM) was adopted. The simulation utilised the optimal parameters employed in the laboratory to produce the samples. The geometry for the modelling was 2D axisymmetric as the parameters were based on temperature-dependent characteristics noting that only the sintered sample was modelled and simulated in order not to simplify the modelling. The FEM maintained constant sintering temperature, pressure, and heating rate but concentrated on the impact of residence durations. To verify the simulation results, morphological alterations and densification validation tests were conducted. The microstructural characterization of the sintered sample demonstrated the relationship between the stress distribution and computational temperature found in the current FEM. Noting good particle-to-particle necking. From the model, results showed that the sintered sample at different points depicted a yield stress far greater than the von Mises stress with least thermal stress at 30 MPa. This validate that the developed sample is mechanically stable based on the factor of safety failure criterion and design. However, the study recommend that further work should be conducted considering different sintering pressure of variation 10 to 30 MPa.

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.

Field-assisted sintering of low-temperature thermoelectric material BiTeSe - sintering process and part characterisation

Field-Assisted Sintering Technology (FAST), an advanced consolidation technique, was employed to synthesise low-temperature thermoelectric n-type Bi2Te2.7Se0.3 for energy harvesting applications. A systematic investigation of sintering parameters, including pressure, temperature, holding time, and heating rates, was conducted to optimise the material’s properties. Post-sintering characterisation encompassed measurements of relative density, thermal conductivity, electrical resistivity, and Seebeck coefficient. Factor analysis revealed the hierarchical influence of sintering variables, with temperature emerging as the most critical parameter, followed by pressure and holding time. The study successfully identified optimal FAST sintering conditions for Bi2Te2.7Se0.3, resulting in enhanced thermoelectric properties. This research demonstrates the efficacy of FAST in producing high-quality, low-temperature thermoelectric materials and provides valuable insights into the relationship between processing parameters and material performance.

Influence of heat sintering on the physical properties of bulk La0.67Ca0.33MnO3 perovskite manganite: role of oxygen in tuning the magnetocaloric response.

The effect of heat treatments on bulk poly-crystalline La0.67Ca0.33MnO3 perovskite manganite is presented, to explore the possible enhancement in magnetocaloric performance. Samples were prepared via conventional solid-state reaction route with annealing and sintering at various temperatures. Detailed measurements of temperature-dependent and field-dependent magnetization were carried out to estimate the Curie point and order of magnetic transition. The increased sintering temperature results in a steep transition near the TC, and establishes the magnetic sensitivity as well as the active zone for substantial magnetocaloric performance, at about 168.2% for the LCM9 (sintered at 900 °C) sample. The cause for the significant improvement in the magnetic and magnetocaloric response is brought to light using detailed X-ray photoelectron spectroscopy (XPS) analysis, highlighting the role of oxygen in modifying the Mn3+/Mn4+ charge ratio. The maximum value of the isothermal magnetic entropy change for the optimized sample is found to be 6.4 J kg-1 K-1, achieved at 269 K, while temperature-averaged entropy change (TEC) values, TEC(ΔTH-C = 3 K) and TEC(ΔTH-C = 5 K), of 6 J kg-1 K-1 and 5.2 J kg-1 K-1, respectively, were obtained with a low magnetic field change of 20 kOe. The obtained isothermal entropy change at low field for the optimized La0.67Ca0.33MnO3 sample is higher than that of pure Gd and most oxide-based materials. The relative cooling power (RCP) value is around 93 J kg-1 (ΔH = 20 kOe). The order of the phase transition is examined with universal scaling; the scaled entropy change curves confirm the collapse onto a single curve for LCM9, asserting second-order character, whereas the breakdown of the curve with a dispersion relation (d) of 101.1% at Θ = -5 confirms the onset of intrinsic first-order nature in the case of the high-temperature-sintered samples. Calorimetry measurements show thermal hysteresis of 2.4 K and 7.1 K for LCM11 (sintered at 1100 °C) at ramp rates of 5 K min-1 and 10 K min-1, respectively, confirming the first-order nature of the magnetic transition.