Oxide Carbide Research Articles

Influence of Varying Particle Size on Mechanical & Tribological Properties of A356-Al2O3 Metal Matrix Composites

MMCs represent a new generation of engineering materials in which a strong ceramic reinforcement is incorporated into a metal matrix to improve its properties including specific strength, specific stiffness, wear, corrosion resistance and elastic modulus. Aluminium oxide and silicon carbide powders in the form of fibers and particulates are commonly used as reinforcements in MMCs and the addition of these reinforcements to aluminum alloys has been the subject of a considerable amount of research work. Aluminum oxide and silicon carbide reinforced aluminum alloy matrix composites are applied in the automotive and aircraft where the tribological properties of these materials are considered important. Therefore, the development of aluminum matrix composites is receiving considerable emphasis in meeting the requirements of various industries. An economical way of producing metal matrix composite is the incorporation of the particles into the liquid metal and casting which leads to improvement in strength over the unreinforced alloy. Addition of particulate reinforcement improves stiffness, strength and tribological properties. Particle size also influences the uniformity of distribution of reinforcement in the matrix. Smaller the particle size, higher will be the agglomerate content in the composite structure. Particle also directly influences the porosity content in the composite structure.The purpose of research in Tribology is understandably the minimization of losses resulting from friction and wear at all levels of technology where the rubbing of surfaces is involved. The present work is a small attempt made to study the influence of reinforcement particulate size on the mechanical and tribological characteristics of Al-Al2O3p composites.

Fabrication of hafnium-based nanoparticles and nanostructures using picosecond laser ablation

This work presents a unique and straightforward method to synthesise hafnium oxide (HfO2) and hafnium carbide (HfC) nanoparticles (NPs) and to fabricate hafnium nanostructures (NSs) on a Hf surface. Ultrafast picosecond laser ablation of the Hf metal target was performed in three different liquid media, namely, deionised water (DW), toluene, and anisole, to fabricate HfO2 and HfC NPs along with Hf NSs. Spherical HfO2 NPs and nanofibres were formed when Hf was ablated in DW. Hf ablated in toluene and anisole demonstrated the formation of core–shell NPs of HfC with a graphitic shell. All NPs exhibited novel optical reflectance properties. Reflectance measurements revealed that the fabricated NPs had a very high and broad optical absorption throughout the UV–vis–NIR range. The NPs synthesised in toluene exhibited the best absorption. The successful fabrication of Hf NSs with the formation of laser-induced periodic surface structures (LIPSS) with low spatial frequency (LSFL) and high spatial frequency (HSFL) orthogonal to each other was also demonstrated. The LSFL and HSFL both exhibited quasi-periodicity. This work presents a simple way to fabricate HfO2 and HfC NPs and provides insight into their morphological and optical characteristics paving way for their applications in future.

Experimental study on the impact of hybrid GFRP composites with graphene oxide and silicon carbide fillers on mechanical and wear properties

Recently, there has been a rapid increase in the demand for manufacturing reliable and innovative components. FRP composites are ideal for various engineering applications due to their low cost, lightweight, high strength-to-weight ratio, mechanical properties, and heat resistance. This research focuses on fabricating GFRP composites with graphene oxide (GO) and silicon carbide (SiC) fillers using the hand-layup method. Mechanical tests were performed using UTM, and wear testing was conducted through fretting wear analysis. The outcomes reveal that the optimal mechanical characteristics, including tensile strength, flexural strength, and short beam strength (SBS), were 242.73 MPa, 317.13 MPa, and 40.05 MPa, respectively, at a 0.5 wt.% GO filler concentration. The laminate composite achieved a maximum tensile and flexural modulus of 8.03 GPa and 13.59 GPa correspondingly with the incorporation of 0.5% GO micro-fillers to the epoxy matrix with respect to the NE composite, due to improved interfacial bonding between the matrix and filler. Additionally, the best wear resistance in the laminate composite was observed with a hybrid micro-filler combination of 1% SiC and 1% GO introduced into the polymer matrix, leading to minimal material removal from the GFRP laminate composite. The worn surfaces of the composites were analyzed using (FE-SEM) to explore potential wear mechanisms. It was revealed that during the initial phases of wear, the participation of the fillers plays a substantial role in the GFRP composite. The introduction of hybrid fillers into composite renders it an encouraging material for industrial purposes requiring exalted strength and exceptional wear resistance.

THE TECHNOLOGY OF OBTAINING POWDERS USED IN THE PRODUCTION OF SOLID ALLOYS

The scientific and practical study on contemporary technologies and methods for generating powders (cobalt and tungsten carbide)-the building blocks of tungsten carbide-cobalt-based solid alloys that are widely utilized in the mining and metallurgy industries-is presented in this article. In the course of research, it was studied how to obtain pure cobalt powder from cobalt oxide and pure tungsten carbide powder from tungsten oxide. Cobalt is a binder that affects the hardness, brittleness, density, bending strength, tempering temperature and abrasive wear resistance of hard alloys. The binder is required to be sufficiently flexurally strong, tough and resistant to abrasive wear under operational conditions and this requires obtaining pure cobalt powder. Today, the main raw materials for the production of hard alloys at the “SPA to produce rare metals and the hard alloys” under “Almalyk MMC” JSC are brought from the waste cakes in the territory of the SPA and the Ingichka mine located in the Samarkand region and hydrometallurgically processed tungsten oxide takes up to (WO3).To solve this task, the electron microscopic method was used during the research. All studies were performed on a JSM-IT200 (JEOL, Japan) scanning electron microscope at the “Uzbekistan-Japan Youth Innovation Center”.

Preparation, Purification, and Hydrophilization of Magnetic-Carbon Nanofibers

This study aims to synthesize, purify, and modify magnetic carbon nanofibers (Mag-CNF) into hydrophilic carbon material. The synthesis method was carried out by chemical vapor deposition (CVD) using the catalyst from Incolloy at 800°C with argon, nitrogen, hydrogen, and acetylene gases. The purification of Mag-CNF was then conducted by dissolving Mag-CNF with toluene and ethanol, followed by vacuum annealing. The hydrophilization of Mag-CNF was further performed by adding amine groups via reacting Mag-CNF with ethylene diamine, NaNO2, and H2SO4. The successfully prepared Mag-CNF has characteristics of tubular tube bundles consisting of carbon nanofibers with an average diameter of 100-120 nm. The X-ray diffraction (XRD) profile shows the characteristics of carbon, iron, iron oxide, and iron carbide. The Raman spectra show the existence of D, G, and G' bands corresponding to the characteristics of carbon nanomaterials. The magnetic property characterization using a vibration sample magnetometer (VSM) shows the synthesized product as ferrimagnetic materials. The modification results show the addition of hydrophilic groups to Mag-CNF, such as O–H and N–H groups, as analyzed in Fourier Transform Infrared (FTIR) spectra. The successful hydrophilization was also visually confirmed using a dispersion test in water, showing that Mag-CNF has better dispersion after surface modification.

Sensitive Electrochemical Determination of Quercetin in Fruit Juice Using an Aluminum Hydroxide Oxide–Titanium Carbide MXene Composite

A hybrid material composed of aluminum hydroxide oxide (AlOOH) and titanium carbide (Ti3C2) nanosheets was synthesized and used for electrochemical sensing of quercetin. The Ti3C2 nanosheets were synthesized using a selective etching technique, followed by the hydrothermal growth of AlOOH on the nanosheet surfaces. Cyclic voltammetry and differential pulse voltammetry were performed to evaluate the electrochemical properties of the AlOOH@Ti3C2 nanocomposites. Under optimal conditions, the AlOOH@Ti3C2 modified electrode exhibited wide linearity and high sensitivity. The practicality of the sensor was verified through an interference study and real sample analysis. Additionally, the sensing platform exhibited outstanding operational and storage stability.

Harnessing nano-synergy: A comprehensive study of thermophysical characteristics of silver, beryllium oxide, and silicon carbide in hybrid nanofluid formulations

Nanofluids, promising to improve heat transfer efficiency, encounter stability and durability challenges, hindering their industrial applications. The emerging concept of hybrid nanofluids, alongside surfactant-driven stability research, presents a promising solution to tackle challenges in heat transfer, potentially revolutionizing thermal management systems and advancing nanomaterial science. This comprehensive study investigates the thermophysical properties of simple and hybrid nanofluid formulations composed of silver (Ag), beryllium oxide (BeO), and silicon carbide (SiC) nanoparticles dispersed in water. Hybrid nanofluids were prepared with varying volumetric ratios of 20:80, 40:60, 60:40, and 80:20 and examined across temperatures ranging from 15 to 45 °C. The influence of surfactants on stability was explored to augment thermal characteristics. Results revealed that the surfactants have a significant effect on stability and the specific mixing ratios can lead to more favourable thermal characteristics. Thermal conductivity enhancements, evaluated via the transient hot-wire method, demonstrated improvements of 7.43 %, 7.17 %, and 5.31 % for Ag/SiC (60:40), Ag/BeO (60:40), and SiC/BeO (80:20) hybrid nanofluids, respectively, compared to water. Viscosity measurements revealed Newtonian behaviour for the Ag, SiC, and BeO nanofluids, with a minimum viscosity enhancement of 3.01 % observed for the BeO nanofluid. Hybrid Ag/SiC nanofluid demonstrated a maximum viscosity enhancement of 4.90 % for 20:80 formulation. Density analysis showed maximum augmentation of 0.25 %, 0.097 %, and 0.0775 % for the Ag, SiC, and BeO nanofluids respectively at 0.025 vol% while hybrid Ag/SiC nanofluid exhibited a maximum of 0.23 % density increase for the 80:20 composition. The statistical models were also developed to predict properties against temperature. Furthermore, the cost analysis identified Ag nanofluid as the most expensive option, while the SiC/BeO hybrid was the most economical. However, the Ag-SiC (60:40) hybrid nanofluid offered a balanced trade-off between properties and cost.

Ni-based compounds in multiwalled graphitic shell for electrocatalytic oxygen evolution reactions

Here, we report a general strategy for designing a metal/carbon system, via a facile and environmentally friendly one-step approach, from metal acetate as an active electrocatalyst in oxygen evolution reaction (OER) during water decomposition. As a demonstration, a nanostructured Ni/C composite induced from nickel acetate is revealed in great detail. The resulting material is composed of: metallic nickel (Ni), nickel(II) oxide (NiO), and nickel carbide (Ni3C) coated with a graphitic shell and deposited on a carbon platform. Our findings underscore the prominent role of nickel species, including Ni0, Ni2+, and Ni3+, in driving the catalytic activity. Notably, the catalyst exhibits an overpotential of 170 mV, a Tafel slope of 49 mV·dec−1, an electrocatalytic surface area (ECSA) of 964.7 cm2, and a turnover frequency (TOF) value of 52.8 s−1, surpassing RuO2. The Raman spectra also suggest a graphitic "self-healing" phenomenon post-OER, attributed to the reduction of oxygen-containing groups. Carbon in the system (i) facilitates electron transfer, (ii) allows homogeneous distribution of Ni nanoparticles avoiding their agglomeration, and (iii) promotes durability of the electrocatalyst by serving as a protective barrier, shielding the core metal compounds. What is more, density functional theory (DFT) calculations allowed to optimized geometry of the model cluster Ni8O8(OH)8 describing two different sites on the β-NiOOH surface (001) and two different intermediates, (i)L-OOH and (ii)L-OOH. This facilitated to propose the reaction mechanisms involving both hydroxide ions and water molecules as reducers. Therefore, the chemisorption of OH− and H2O molecules at the NiOOH active center accompanied by bond breakage and the formation of a lattice hydroperoxide as an important intermediate is presumed. What is more, the proposed fabrication method for electroactive metal/carbon composites was validated with an iron and iron/nickel mixture.

Ti4Fe2C0.82O0.18.

The phase with composition Ti4Fe2C0.82O0.18, tetra-titanium diiron carbide oxide, was unexpectedly synthesized by high-pressure sinter-ing (HPS) of a stoichiometric mixture with nominal composition Ti2Fe. The Ti4Fe2C0.82O0.18 phase crystallizes in the Fd m space group and can be considered as the Ti2Fe structure filled with C and O atoms co-occupying the same octa-hedral void [occupancy ratio 0.82 (7):0.18 (7)]. The Ti4Fe2C0.82O0.18 phase is isotypic with Ti4Ni2C and Ti4Fe2O0.407, and is the first example where C and O atoms co-occupy the same site in filled Ti2Fe structures.

(Electronics and Photonics Division Poster Award Winner) A High Breakdown Voltage Silicon Carbide (SiC)/Gallium Oxide (Ga2O3) Heterojunction Diode for High Power Applications

Wide and ultrawide bandgap semiconductors demonstrate exceptional performance due to their elevated energy bandgap. This characteristic results in breakdown electric fields surpassing those found in conventional silicon electronics by more than an order of magnitude. Furthermore, the high energy bandgap offers distinctive advantages, including enhanced efficiency, drift velocity, increased voltage blocking, and high-frequency switching, making these semiconductors crucial in pushing the boundaries of electronic technology. Gallium Oxide and Silicon Carbide, distinguished by their unique properties, contribute significantly to the advancement of power electronics. Gallium Oxide, with its wide bandgap of 4.6 – 4.9 eV and excellent thermal stability, stands out for its ability to handle high electric fields and temperatures. Silicon Carbide, on the other hand, boasts a robust combination of high thermal conductivity and a wide bandgap of 3.26 eV, making it well-suited for high-power and high-temperature applications. The combination of these two materials in a heterojunction holds promise for the development of high-performance power devices. In this study, we propose a novel high breakdown voltage Silicon Carbide (SiC)/ Gallium Oxide(Ga2O3) heterojunction diode through TCAD Sentaurus. We present a comparative study of the breakdown voltage and electric field across different heterojunction lengths and under various doping concentrations. The investigated heterojunction showcases a high breakdown voltage of 1899V, making it a promising candidate for advanced power electronics applications. Furthermore, simulation results revealed a significant increase in the breakdown voltage of the SiC/Ga2O3 heterojunction, escalating from 1899 V to 4864 V when extending the heterojunction length. Improved specific ON resistance (RON, sp) and Baliga figure-of-merit (BFOM) will also be presented.

Displacement damage effect of proton irradiation on vertical β-Ga2O3 and SiC Schottky barrier diodes (SBDs)

In this study, we fabricated vertical Schottky barrier diodes (SBDs) based on wide bandgap semiconductor beta-phase gallium oxide (β-Ga2O3) and silicon carbide (SiC), respectively, and conducted proton irradiation experiments to analyze the radiation hardness of the SBDs comparatively. The effects of proton radiation on the performance of SBDs were assessed through measurements of forward current, capacitance, and breakdown characteristics. Both devices exhibited degradation in current and capacitance characteristics following proton irradiation, attributed to displacement damage (DD). Notably, the β-Ga2O3-based SBD demonstrated more pronounced deterioration compared to the SiC-based device despite similar vacancy distributions as confirmed by SRIM simulation. Moreover, a decrease in contact radius correlated with exacerbated degradation in the current characteristics of the β-Ga2O3-based SBD. Following proton irradiation, breakdown voltages of both devices increased due to elevated resistance induced by displacement damage. While both β-Ga2O3 and SiC-based SBDs experienced displacement damage under high fluence proton irradiation, the extent of performance degradation varied depending on the dimensions and quality of epitaxial and substrate layers.

Ultrafast 2D Nanosheet Assembly via Spontaneous Spreading Phenomenon.

In 2D materials, a key engineering challenge is the mass production of large-area thin films without sacrificing their uniform 2D nature and unique properties. Here, it is demonstrated that a simple fluid phenomenon of water/alcohol solvents can become a sophisticated tool for self-assembly and designing organized structures of 2D nanosheets on a water surface. In situ, surface characterizations show that water/alcohol droplets of 2D nanosheets with cationic surfactants exhibit spontaneous spreading of large uniform monolayers within 10s. Facile transfer of the monolayers onto solid or flexible substrates results in high-quality mono- and multilayer films with high coverages (>95%) and homogeneous electronic/optical properties. This spontaneous spreading is quite general and can be applied to various 2D nanosheets, including metal oxides, graphene oxide, h-BN, MoS2, and transition metal carbides, enabling on-demand smart manufacture of large-size (>4 inchϕ) 2D nanofilms and free-standing membranes.

Reduction in Powder Wall Friction by an a-C:H:Si Film

The wall friction angle is an important parameter in powder flow. In a recent study for various powders, a reduction in the wall friction angle for steel was demonstrated by the application of an a-C:H:Si film on the steel surface. This work presents the results of a study of this effect in more detail regarding the influence of the powder material, the wall normal stress and the particle size of the powder for mass median diameters from 4 µm to approximately 150 µm. The wall friction angles were measured using a Schulze ring shear tester for three different powder materials: aluminum oxide, calcium carbonate and silicon carbide. The results showed little difference with respect to powder chemistry. For the coarser powders, the reduction in the wall friction angle due to the a-C:H:Si coating was highest (10° to 12°) and rather stress-independent, while for the fine and medium-size powders the reduction was lower and stress-dependent. With increasing wall normal stress, the reduction in the wall friction angle increased. These results can be explained by the friction reduction mechanism of a-C:H:Si, which requires a certain contact pressure for superficial graphitization.

WLI, XPS and SEM/FIB/EDS Surface Characterization of an Electrically Fluted Bearing Raceway

Electrical bearing currents may disturb the performance of the bearings via electro-corrosion if they surpass a limit of ca. 0.1 to 0.3 A/mm2. A continuous current flow, or, after a longer time span, an alternating current or a repeating impulse-like current, damages the raceway surface, leading in many cases to a fluting pattern on the raceway. Increased bearing vibration, audible noise, and decreased bearing lubrication as a result may demand a replacement of the bearings. Here, an electrically corroded axial ball bearing (type 51208) with fluting patterns is investigated. The bearing was lubricated with grease lubrication and was exposed to 4 A DC current flow. It is shown that the electric current flow causes higher concentrations of iron oxides and iron carbides on the bearing raceway surface together with increased surface roughness, leading to a mixed lubrication also at elevated bearing speeds up to 1500 rpm. The “electrically insulating” iron oxide layer and the “mechanically hard” iron carbide layer on the bearing steel are analysed by WLI, XPS, SEM, and EDS. White Light Interferometry (WLI) is used to provide an accurate measurement of the surface topography and roughness. X-ray Photoelectron Spectroscopy (XPS) measurements are conducted to analyze the chemical surface composition and oxidation states. Scanning Electron Microscopy (SEM) is applied for high-resolution imaging of the surface morphology, while the Focused Ion Beam (FIB) is used to cut a trench into the bearing surface to inspect the surface layers. With the Energy Dispersive X-ray spectrometry (EDS), the presence of composing elements is identified, determining their relative concentrations. The electrically-caused iron oxide and iron carbide may develop periodically along the raceway due to the perpendicular vibrations of the rolling ball on the raceway, leading gradually to the fluting pattern. Still, a simulation of this vibration-induced fluting-generation process from the start with the first surface craters—of the molten local contact spots—to the final fluting pattern is missing.

Temperature-Induced Interface Hybridization of WC Boosts NiCu Activity for Alkaline Hydrogen Oxidation Reaction.

The development of non-precious hydrogen oxidation reaction (HOR) catalysts is a major challenge for the commercialization of Pt-free fuel cells. Herein, a temperature-induced phase hybridization method is reported that greatly improves the catalytic performance of NiCu alloy for the HOR. The migration of W atoms hybridizes the interface of tungsten oxide (WOx) and tungsten carbide (WC) at the onset reduction temperature of WOx, leading to a greatly weakened H binding energy and an optimized OH binding energy, which endows NiCuW/WOx-WC@WC with favorable stability and CO resistance during HOR. The hybridization catalysts deliver a high mass activity of 29.37 mA mg-1 Ni and reach a peak power of 298 mW.cm-2 in H2-O2 anion exchange membrane fuel cells (AEMFCs).

Titanium Carbon Oxide Flakes with Tunable Interlayer Spacing for Efficient Capacitive Deionization

AbstractThe environmental toxicity caused by heavy metal ions is always taken seriously. Capacitive deionization (CDI), as an emerging and effective treatment method, is widely studied. Among them, the rational design and development of efficient electrodes based on high theoretical capacitance, high conductivity, and high stability have great prospects for CDI applications. In this study, a series of 2D titanium carbide oxide flakes (2D TCOs) are synthesized using a cation‐giving modulation strategy, and the interlayer spacing of materials is successfully controlled by confining cations (tetraalkylammonium hydroxides, TAAH) with different radii between layers. Interestingly, these TCOs exhibit widely varying electrochemical properties due to their different interlayer spacings. Among them, titanium carbide oxide flakes‐tetrapropylammonium hydroxide (TCOs‐TPAH) with the maximum interlayer spacing exhibits the best performance in sodium ion embedding and de‐embedding, with a capacity of 53.11 mg g−1. In addition, the capacitive removal efficiency of heavy metal ions (Fe3+, Cr3+, Cu2+, Cd2+, Co2+, Ni2+, and Pb2+) can reach over 97% within 2 h. This work presents a simple and creative strategy for the bottom‐up synthesis of oversized 2D nanomaterials, thus supporting the further development of high‐performance 2D materials in the fields of environmental and energy applications.

Tribology, corrosion, and tribocorrosion performance of aged lightweight steels: Effects of oxide film and carbide

The study investigated the tribology, corrosion, and tribocorrosion performance of aged Fe–30Mn–8Al–1.2 C–0.1Ti–(2Cr/Mo) steel, with a focus on oxide film and carbide. The precipitates changed from κ carbide to Cr7C3/MoC with the addition of Cr/Mo. The inhomogeneous precipitation of Cr7C3/MoC created zones of varying hardness, one being hard with strong strengthening and the other soft with weak strengthening. The inhomogeneous hardness distribution deteriorates the tribology performance of the steel. By minimizing galvanic coupling corrosion and improving the protectiveness of the oxide film, the addition of Cr/Mo can improve the corrosion and tribocorrosion resistance of lightweight steel.

Investigating the effect of simultaneous incorporation of Al2O3 and B4C nanofillers in enhancing the wear performance of UHMWPE

AbstractDuring the past years, great effort has been made to improve the tribological performance of ultra‐high molecular weight polyethylene (UHMWPE), considered a key polymeric material in applications requiring elevated mechanical and corrosion resistance and bioinertness. This work aimed to investigate the role of adding ceramic nanofillers of aluminum oxide (Al2O3) and boron carbide (B4C) in the UHMWPE matrix in order to modify the triboperformance of the polymer. The results obtained through dry reciprocating sliding tests up to 6 h (21,600 cycles) revealed that the presence of nanoparticles has led to a 33% higher coefficient of friction on average when compared with the matrix polymer without nanofillers. This behavior results from the increased resistance to plowing caused by the nanofillers, which contributes to the frictional force. Conversely, the simultaneous utilization of both nanofillers, each one at a concentration of 1.5% by mass, significantly enhances the wear resistance of UHMWPE, achieving a reduction in wear of over 35%.

A metallurgical approach for separation and recovery of Cu, Cr, and Ni from electroplating sludge

Electroplating sludge is extensively produced in chemical precipitation–based treatment of electroplating wastewater. It poses a huge threat to environmental safety if not properly disposed, ascribed to its high contents of heavy metals. An innovative metallurgical approach was proposed a to recycle Cu, Cr, and Ni from it. Ammonia leaching was firstly performed to selectively leach Cu from Cr, in which the Cu oxide and sulfide were leached into the leachate while the Cr oxide and Ni carbide (NiCx) retained in the residue. (NH4)2SO4 increased the Cu leaching rate via increasing the dissolved oxygen amount in the ammonia leachate and converting CuS to Cu2+. Under the optimal conditions, the leaching efficiency of Cu achieved 96.5 % while that of Cr was only 0.1 %. In the followed aluminothermic reduction, C in the leaching residue could be effectively removed via a thermal oxidation, which in turn decreased the formation of a C-containing compound of high melting point and benefited the Cr and Ni recovery. Cr and Ni from the residue were reduced and recovered in a Cr-Ni alloy, and the reductant of Al first changed to a refractory Al2O3 and then transformed to a low melting point 12CaO·7Al2O3 with the additive of CaO. This transformation increased the molten slag fluidity and promoted the separation of Cr-Ni alloy from slag. Moreover, the excessive Al increased the Cr and Ni yields and concentrated all of them to be together. Partial Al was used as reductant, and the other Al transferred into Cr-Ni alloy to decrease its melting point. Cr and Ni contents in the smelting slag could be decreased to 0.11 wt% and 0.12 wt% respectively, showing an efficient recovery. This work provided a high efficiency method to recover Cu, Cr, and Ni from waste electroplating sludge.

Characterization of carbon-coated core-shell iron nanoparticles annealed by oxygen and nitrogen

Nanocomposites consisting of nanoparticles of iron oxide (Fe3O4) and iron carbide (Fe3C) with a core-shell structure (Fe core, Fe3O4 and/or Fe3C shells) coated with additional graphite-like carbon layer dispersed in carbon matrix have been synthesized by solid-phase pyrolysis of iron-phthalocyanine (FePc) and iron-porphyrin (FePr) with a pyrolysis temperature of 900°C, and post-annealing conducted at temperatures ranging from 150°C to 550°C under controlled oxygen- and/or nitrogen-rich environments. A comprehensive analysis of the samples’ morphology, composition, structure, size, and magnetic characteristics was performed by utilizing scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-STEM) with elemental mapping, X-ray diffraction analysis (XRD), and magnetic measurements by utilizing vibrating sample magnetometry (VSM). The effect of the annealing process on magnetic performance and efficient control of the hysteresis loop and specific absorption rate (SAR) are discussed.