Final Heat Treatment Temperature Research Articles

Golub N.P., Golub E.O., Kozma A.A., Hlebena H.F., Mikhalchuk H.M., Kuznietsova A.O. SYNTHESIS AND RESEARCH OF A COMPLEX MANGANESE-NICKELPHOSPHATE CATALYTIC SYSTEM

Individual Mn2P2O7 and Ni3(PO4)2 phosphate catalysts were synthesized. A new synthesis technique was developed and a new complex catalytic system хMn2P2O7×yNi3(PO4)2 was obtained based on them (К-1 – К-7), which has the predicted physicochemical properties. The composition of these phosphates in the structure of the catalyst was varied in the range of 0,5 – 99,5 wt.%. It was established that the conditions of synthesis of catalysts significantly influence the process of forming the composition, structure, and corresponding physicochemical parameters of the synthesized catalysts. On the thermogram of the differential thermal analysis of an individual manganese-phosphate catalyst, three endo-effects at 148°С, 220°С and 353°С and one exo-effect at 460°С are observed. The thermogram of individual Ni3(PO4)2 shows two endo-effects at 210°С and 372°С and one exo-effect at 803°С. The synthesized double manganese-containing systems are characterized by a significant difference in DTA curves for samples K-1 - K-7. All obtained air-dry samples are crystal hydras with different numbers of water molecules. The structure of the obtained series of complex manganese-nickel phosphate catalysts contains various forms of water. The process of dehydration contributes to its separation from the structure of the samples and leads to the occurrence of characteristic endothermic effects. On all synthesized complex samples, the transition of manganese (II) orthophosphate to its pyrophosphate is observed when the final heat treatment temperature is reached. Firing samples of synthesized catalysts above 700oC leads to their complete dehydration with the formation of anhydrous salts. DTA results for all synthesized manganese-nickel phosphate samples are in good agreement with their X-ray diffraction, IR spectroscopy, and surface acidity results. They confirmed the correct choice of the modifying ion to improve the structure and physicochemical parameters of the manganese (II) phosphate catalyst. It can be predicted that the synthesized new complex oxide catalysts will show improved catalytic properties (activity and selectivity) in the processes of partial oxidation of n-alkanes into valuable products. The synthesized double manganese-containing systems are characterized by a significant difference in DTA curves for samples K-1 - K-7. All obtained air-dry samples are crystal hydras with different numbers of water molecules. The structure of the obtained series of complex manganese-nickel phosphate catalysts contains various forms of water. The process of dehydration contributes to its separation from the structure of the samples and leads to the occurrence of characteristic endothermic effects. On all synthesized complex samples, the transition of manganese (II) orthophosphate to its pyrophosphate is observed when the final heat treatment temperature is reached. Firing samples of synthesized catalysts above 700oC leads to their complete dehydration with the formation of anhydrous salts. DTA results for all synthesized manganese-nickel phosphate samples are in good agreement with their X-ray diffraction, IR spectroscopy, and surface acidity results. They confirmed the correct choice of the modifying ion to improve the structure and physicochemical parameters of the manganese (II) phosphate catalyst. It can be predicted that the synthesized new complex oxide catalysts will show improved catalytic properties (activity and selectivity) in the processes of partial oxidation of n-alkanes into valuable products.
 Keywords: catalysis; catalyst; catalytic systems; complex oxides; heterogeneous catalysis; phosphates; oxidation; n-alkanes; hydrocarbons; ethane; ethylene; differential thermal analysis.

Modification of accelerated thermal stabilization of polyacrylonitrile fibers by creating an oxygen concentration gradient in the production of carbon fiber

Objectives. The work set out to modify the technology of accelerated thermal stabilization of polyacrylonitrile (PAN) fibers used in the production of high-strength carbon fibers by reducing the formation of a heterophase core–shell structure to create an oxygen concentration gradient in heat treatment furnaces while maintaining a total thermal stabilization time of 30 min. The optimized process conditions led to milder thermal stabilization conditions, reducing both the final heat treatment temperature and the temperature difference between the thermal stabilization zones while simultaneously maintaining the target volume density parameter with respect to the previously developed accelerated thermal stabilization technology.Methods. The thermal stabilization study of an industrially produced 12S precursor under different conditions on an experimental carbon fiber production line included measurement of bulk density, analysis of the thermal effects of the oxidation reaction by differential scanning calorimetry (DSC), and a study of micrographs of the resulting samples.Results. The optimum process of thermal stabilization of PAN fiber was determined in four stabilization zones using selected compositions. The formation of the core–shell structure is significantly reduced when the target volume density and DSC thermal oxidation reaction effect of the stabilized polymer fiber are achieved in a given time (30 min).Conclusions. The resulting technology regime is promising for the production of high strength (4.5 GPa, 4.9 GPa) PAN fibers at a reduced cost. While maintaining the total thermal stabilization time of PAN at the level of 30 min, which is three times less than the industrial processes used, it was possible to reduce the formation of a heterophase structure, as well as lowering the final processing temperature and reducing the temperature difference between the stabilization zones. This is promising in terms of a positive effect on the stability and safety of the industrial process, as well as ensuring the quality of the obtained products.

INFRARED SPECTROSCOPIC ANALYSIS OF COMPLEX OXIDE CATALYST 50%Cu3(PO4)2•50%Ni3(PO4)2

It is established that the frequencies and intensities of the absorption bands of the infrared spectra of the obtained air-dried sample 50%Cu3(PO4)2∙50%Ni3(PO4)2 and calcined at the optimum heat treatment temperature of 600оС are characterized by significant absorption in the valence (3460-3020 cm-1) and strain (2360-1400 сm-1) vibrations of hydroxyl OH-groups of water molecules. Valence vibrations of phosphate ion are most manifested in dehydration products in the form of clear bands in the absorption frequency range 1110-410 сm-1. For the investigated sample, three absorption bands were observed in the region: 3188,72 сm-1, 1621,84 сm-1 та 1434,78 сm-1. They confirm the existence of two types of crystalline hydrate water molecules, which are characterized by different hydrogen bonding energies. In the process of heat treatment of the synthesized sample in the temperature range of 120-700оС , the process of dehydration occurs. In this case, the intensity of the absorption bands in the region of valence and strain vibrations of water molecules gradually decreases in the obtained IR spectra. The phenomenon of complication of the spectrum of orthophosphate ion by additional absorption bands is obviously associated with the distortion of the tetrahedron structure in real crystals and the reduction of its symmetry. It can be a consequence of both low symmetry of the environment and perturbation of the orthophosphate anion РО43– by water molecules when intermolecular hydrogen bonds occur. It may also be due to possible additional coordination of orthophosphate anion with metal cations Сu2+ and Ni2+. Calcination of the sample at the final heat treatment temperature of 700оС leads to an anhydrous orthophosphate system. This will lead to a decrease in the value of surface acidity and catalytic inertness of the sample.
 Keywords: catalysts; heterogeneous catalysis; phosphates; complex oxides; oxidation; n-alkanes; hydrocarbons; ethane; ethylene; IR spectroscopy.

Zn1-xCoxO vs Ag-ZnO photoanodes design via combustion: Characterization and application in photoelectrocatalysis

In this work, different synthetic conditions were analyzed to prepare modified ZnO photoelectrodes, in order to prevent the recombination of their photogenerated charge carriers and thus allow the continuous formation of electrons and holes on photoelectrocatalytic reactions. Thus, an investigation was carried out by the chemical modification using cobalt and surface modification using silver, as well as the final heat treatment temperature, to monitor its effects onto the properties of this semiconductor oxide. In this context, Zn1−xCoxO and Ag-ZnO photoelectrodes were produced from combustion synthesis and prepared simply and efficiently, directly on the indium tin oxide (ITO) surface. These material modifications were efficient to improve the properties of pure ZnO, and the presence of silver on the ZnO surface provided significantly superior photoelectrochemical and photoelectrocatalytic responses for methylene blue discoloration. Zn1−xCoxO presented a current density of 132 μA cm−2 and kinetic discoloration constant of 9.05 × 10−3 min−1, and Ag-ZnO displayed a current density of 162 μA cm−2 and kinetic discoloration constant of 15.0 × 10−3 min−1. Among the ZnO modification conditions, the addition of 2.0% (mol L−1) of a metal nitrate precursor (either Co or Ag) and thermal treatment at 600 °C provided the best responses to the photoelectrodes.

Synthesis of CuO thin films based on Taguchi design for solar absorber

In this research, the effect of the control condition on the physical properties of Copper Oxide (CuO) thin-film has been successfully performed through the sol-gel procedure followed by spin coating technique on a glass substrate. Taguchi model was reported to find the most prominent factor on the deposits process of CuO thin coat with an L9 (33) orthogonal array. Besides, from XRD, we deduce the texture coefficient used to determine the S/N ratio. The selected influential parameters are: concentration of Copper (II) ions “Cu2+“, preheating temperature TP and the final heat-treatment temperature Tf. The results showed that the obtained crystals exhibit a uniform and smooth morphology. The energy-dispersive X-ray spectroscopy (EDS) exploits the chemical composition of the prepared films. In addition, the Absorption spectra by UV–vis analysis of the obtained thin films reveal high absorbance in the visible range. In fact, the CuO films showed optimal gap energy of 1.47 eV. However, the prepared thin CuO films by the optimization of the Taguchi model lead to the enhancement of the optical properties and suggested that CuO thin film could be one of the potential solar cell absorbers in PV devices.

Influence of the final heat treatment temperature on the magnetic property losses of Sm(Co,Fe,Cu,Zr)z high temperature magnets

Microstructures of Sm(CobalFe0.12Cu0.07Zr0.02)7 high temperature magnets with different final slow cooling aging temperatures were investigated to uncover the underlying mechanism of magnetic property losses after operating at 500 °C. When the final slow cooling aging temperature is 400 °C, lower than the operating temperature, both remanence and coercivity reduce after operating, and cannot be recovered to the initial state. Such losses stem from the secondary diffusion induced microchemistry change in the high temperature environment, which will seriously shorten its service life. While when the final slow cooling aging temperature is 500 °C or higher than the operating temperature, the remanence slightly reduces but the coercivity remains nearly unchanged after operating, and can be recovered to the initial level. Consequently, our comparative investigations suggest that final aging at temperatures equivalent or higher than the operating temperature can not only provide stable and reliable magnetic properties for application, but also extend the service life of the present Sm-Co-based magnets.

Carbon Paper as a Promising Free Standing Anode for Sodium Ion Batteries

Porous conducting carbon fiber composite papers have been developed by a two-step process. This involves fabrication of carbon fiber preform followed by composite formation. Different composite papers have been developed by varying the final heat treatment temperature of the composite, viz. 800 °C, 1100 °C, 1400 °C, 1800 °C and 2300 °C. The study gives an insight as to how the structure, porosity, morphology, electrical and mechanical properties of the carbon/carbon composites vary with temperature; and further the effect of these variations on the performance of the composites as anode material for Na-ion batteries. The sample heat-treated to 800 °C showed high reversible capacity of 278 mAh g−1 at a current density of 37 mA g−1. Additionally, high columbic efficiency (>99%) and 72% retention of the initial capacity has been demonstrated for 1000 cycles. This exceptional performance is attributed to the small crystallite size, large d-spacing and disordered structure of the sample which favors the insertion/de-insertion of sodium ion into the composite anode. Hence, it seems as a promising anode material for sodium-ion batteries.

Efficient deuterium permeation reduction coating formed by oxidizing the Fe–Cr–Al ferritic steel in reduced oxygen atmosphere at 973 K

Alumina is regarded as one of the most promising candidate tritium permeation barrier (TPB). Through thermal oxidization of Al-contained alloys Fe–Cr–Al, alumina layer with high tritium permeation reduction ability can be obtained. After bonding this kind of materials with structural materials such as reduced activation ferritic/martensitic (RAFM) steels, it can serve as TPB. In this work, efforts have been done to enhance the hydrogen isotope permeation reduction ability of the alumina layer on the Fe–Cr–Al ferritic steel by optimizing the oxidation process. The oxidation temperature of the Fe–Cr–Al ferritic steel is set to 973 K, which is lower than the final heat treatment temperature of the RAFM steel. Three different atmospheres have been employed for the oxidation process of the Fe–Cr–Al ferritic steel. Gas driven permeation (GDP) experiments have been performed to examine the deuterium permeability of the oxidized Fe–Cr–Al ferritic steel. The deuterium permeability of the Fe–Cr–Al ferritic steel oxidized in argon with 1700 ppm oxygen is 104 times lower than that of the RAFM steel at 823 K. The microstructure and chemical composition of the oxide layer of the Fe–Cr–Al ferritic steel oxidized in three different atmospheres has been clarified using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) methods. It is suggested that oxidizing the Fe–Cr–Al ferritic steel at reduced oxygen atmosphere could inhibit the growth of the iron oxide and chromium oxide in the oxide layer, thereby leading to a dense and compact alumina layer that has excellent hydrogen permeation reduction performance.

BaO–Fe2O3 containing bioactive glasses: A potential candidate for cancer hyperthermia

A series of BaO–Fe2O3 bioactive glasses synthesized with the sol-gel technique. In this research, the magnetic properties of prepared bioactive glass were examined to study the potential application of these materials in cancer hyperthermia. To this goal, physical, morphological and, magnetic behavior of synthesized magnetic bioactive glass, were examined. Scanning Electron Microscopy, X-ray Powder Diffraction, and also Transmission Electron Microscopy used to characterize the composition and morphology of the glass nanoparticles. The size of glass particles studied by Laser Particle Size Analyzer (LPSA). Thermal analysis was used to determine the final heat treatment temperature via Differential Thermal Analysis (DTA). To evaluate the magnetic properties of synthesized glasses, Vibrating Sample Magnetometer, and Calorimetric test used.The results of this research showed that BaO–Fe2O3 addition in the glass structure affects the magnetic behavior of the bioactive glass. VSM (Vibrating Sample Magnetometer) and calorimetric test results prove that the magnetic behavior of the glasses increases with the increase of magnetic content. Results showed that BG1010 and BG0515 generate enough heat for the application of these materials in cancer hyperthermia. Considering Cytocompatibility, Bioactivity, and magnetic properties, it seems the BG1010 sample is the best candidate to use in hyperthermia treatments. Finally, this study proves that the prepared bioactive glasses with magnetic content are good candidates in cancer hyperthermia applications.

Anisotropy in creep properties and its microstructural origins of 12Cr oxide dispersion strengthened ferrite steels

The anisotropy in creep properties and its microstructural origins in two oxide dispersion strengthened (ODS) steels (i.e., 12Cr-ODS-IMR and 12Cr-ODS-NIFS) were systematically investigated. Both ODS steels exhibited the anisotropic creep properties. The creep strength in longitudinal directions (LD) or extrusion directions (ED) specimens was better than that in transverse directions (TD) specimens. The microstructural characterizations revealed that both steels had elongated grains along the ED and relatively equiaxed grains in other orientations. Both steels had a streak-like distribution of precipitates along the ED that was composed of Ti-enriched precipitates and nano-scale oxide particles in local area. The fractography of the crept TD and LD specimens suggested that both steels fractured by the mixed ductile and brittle fracture modes. The propagation of cracks and intergranular decohesion along the boundaries of elongated grains were more severe in the TD specimens than in the LD specimens. The combined effects of elongated grain morphology with low grain shape aspect ratio and segregation of precipitates along the ED can explain the anisotropy in creep properties. The anisotropy in 12Cr-ODS-IMR steel was relatively higher than that in 12Cr-ODS-NIFS steel, and the additional cold rolling and lower final heat treatment temperature in 12Cr-ODS-IMR steel were responsible for it.

Formation of Compounds in the Ag2O–Sb2O3–MoO3 System on Heating

This paper presents a detailed study of phase formation processes in the AgNO3–Sb2O3–MoO3 system during heating in air. The compositions of the solid-state reaction products have been determined using thermogravimetry and qualitative X-ray diffraction. The results demonstrate that, at a final heat treatment temperature of 1023 K, synthesis yields a range of Ag2–xSb2–xMo x O6 compounds with the pyrochlore structure and 0.0 ≤ x ≤ 2.0. The structural parameters of the synthesized phases have been refined by the Rietveld method in space group Fd3m and their electrical conductivity has been measured.

The Influence of Thermal Processing on the Properties of Carbon Fibers Based on Polyoxadiazole

The influence of heat treatment on the properties of carbon fibers based on polyparaphenylene-1,3,4-oxadiazole was studied. Dependences of mass loss, shrinkage, linear density and electrical resistance of carbon fibers on the final heat treatment temperature were obtained. It is shown that a decrease in the heating rate leads to an increase in the carbon residue and the linear density of fibers, and a decrease in shrinkage and electrical resistance. It was found that at a final heat treatment temperature of 900 °C for a heating rate of 5 °C/min, the volume resistivity of the elemental carbon fiber material is 2.8 ± 0.2 mΩ.cm. Increasing the final heat treatment temperature and reducing the heating rate leads to an increase in the uniformity of the distribution of electrical resistance along the fiber.

ZrTiAlV alloy grain refining under high-pressure torsion and electric field-assisted heat treatment

To reduce grain size, shorten heat treatment time, and guarantee good comprehensive mechanical properties of ZrTiAlV alloy, we proposed a grain refining technology, which is a combination of electric field-assisted heat treatment and high-pressure torsion. And using this technology we studied ZrTiAlV alloy grain refining. The original material consists of pure phase α, which will be changed into pure phase β at temperatures exceeding 700°C during electric field-assisted heat treatment. The temperature required for the phase α of the high-pressure torsion material to be completely changed into phase β increases obviously. When the torsion pressure is 5GPa, the initial heat treatment temperature is higher than 700°C and the final heat treatment temperature reaches 800°C, only then can the phase α be completely changed into a phase β structure. When the initial heat treatment temperature is higher than 600°C, the large grains of phase β contain a large amount of sub-grain boundaries, and the sub-grains are smaller than 100μm. When the initial temperature is 700°C, the grains are completely refined and re-crystallization is quite complete. The difference in the orientation angle of the large and small grains is small, indicating continuous dynamic re-crystallization. The original material consists mainly of lath-shape phase α structure; after high-pressure torsion at 4GPa and electric field-assisted heat treatment at 800°C, the phase β structure becomes nearly pure and only a few minor α phase structures are created.

Microstructural changes of polyacrylonitrile-based carbon fibers (T300 and T700) due to isothermal oxidation (1): focusing on morphological changes using scanning electron microscopy

Polyacrylonitrile (PAN)-based carbon fibers have high specific strength, elastic modulus, thermal resistance, and thermal conductivity. Due to these properties, they have been increasingly widely used in various spheres including leisure, aviation, aerospace, military, and energy applications. However, if exposed to air at high temperatures, they are oxidized, thus weakening the properties of carbon fibers and carbon composite materials. As such, it is important to understand the oxidation reactions of carbon fibers, which are often used as a reinforcement for composite materials. PAN-based carbon fibers T300 and T700 were isothermally oxidized in air, and microstructural changes caused by oxidation reactions were examined. The results showed a decrease in the rate of oxidation with increasing burn-off for both T300 and T700 fibers. The rate of oxidation of T300 fibers was two times faster than that of T700 fibers. The diameter of T700 fibers decreased linearly with increasing burn-off. The diameter of T300 also decreased with increasing burn-off but at slower rates over time. Cross-sectional observations after oxidation reactions revealed hollow cores in the longitudinal direction for both T300 and T700 fibers. The formation of hollow cores after oxidation can be traced to differences in the fabrication process such as the starting material and final heat treatment temperature.

Rechargable xLi2MnO3·(1 − x)Li4/3Mn5/3O4 electrode nanocomposite material as a modification product of chemical manganese dioxide by lithium additives

Relatively simple preparation procedure of rechargeable Li-ion battery cathode material via manganese dioxide treatment with Li-containing additive and subsequent calcination has been demonstrated. X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and atomic force microscopy study were characterisation methods of modification products. Pyrolusite, Li0.3MnO2, layered Li2MnO3, and spinel Li4Mn5O12 phases were revealed as products of initial ramsdellite phase transformations at temperatures of heat treatment ranging from 360°C to 600°C. Optimal temperature of final heat treatment from the point of view of rechargeability and discharge characteristics was 450°C. Samples heat-treated at 450°C are characterized by the unique combination of Li4/3Mn5/3O4 and Li2MnO3 phase components due to their structural integration, a significant degree of disordering, and sizes of nanocrystallites with Li diffusion path, which is the most favourable for reversibility. The prepared nanocomposite cathode material delivers a capacity of 150mAhg−1 within 2.5–4.5V at 0.1mA discharge.

Electrophoretic Deposition and Heat Treatment of Steel-Supported PVDF-Graphite Composite Film

Polymeric poly (vinyliden fluoride) (PVDF) is nontoxic. It possesses a better mechanical flexibility and requires a lower synthesis temperature, as compared to the piezoceramic counterparts. In order to achieve a competitive advantage against the current piezoelectric sensor, graphite could replace a more expensive silver-palladium as the electrodes for the piezoelectric PVDF. This paper reports the preliminary results on the synthesis of steel-supported graphite-PVDF/PVDF/graphite-PVDF composite films using the two-step process, consisted of the electrophoretic deposition (EPD) and heat treatment. The composite films were characterized by means of the optical microscopy, scanning electron microscopy, X-ray diffraction and differential scanning calorimetry. The heat treated graphite-PVDF electrode deposited by EPD provides adequate mechanical strength for the subsequent depositions of pure PVDF layer and the second layer of graphite-PVDF composite electrode. However, the final heat treatment stage did not eliminate the fine and large cracks of the composite film, which might be attributed to high residue stresses and weak bonding between graphite and PVDF particles in the post-heat treated composite films. Nevertheless, the increase in final heat treatment temperature of the composite film at Stage 3 improved the graphite and PVDF grain alignment, as well as its crystallinity.

A novel approach to study the effect of heating temperature on prior-austenite microstructure of a Japanese sword

There is uncertainty about heating temperature of final heat treatment and its effect on microstructure of Japanese sword, since the temperature is controlled entirely by experiences and skills of the swordsmith. This study proposed a novel approach to clarify how heating temperature affects prior-austenite microstructure of a Japanese sword. A fragment of the sword was normalized at 800°C to recover its initial microstructure. Specimens were cut and quenched, after being reheated at temperatures from 740 to 860°C with increment step of 20°C. Their prior-austenite microstructure was reconstructed from martensite by using our newly developed automatic reconstruction method. In normalized microstructure of the sword, coarse pearlite islands of 0.70–0.76 mass% C steel were found within a fine ferrite-pearlite matrix of 0.52–0.56 mass% C steel. The prior-austenite grains of the medium C matrix remained fine (11.6 - 15.1 μm) over the temperature range, while abnormal coarse grains (73.9 - 123.7 μm) developed from high C islands in the specimens reheated above 780°C. The prior-austenite microstructure of the original sword was closely similar to that of the specimen reheated at 760°C. It was able to estimate the heating temperature of the original sword to be approximately 760 ± 10°C.

The effect of final heat treatment temperature on radiation response of V–4Cr–4Ti

Neutron irradiation in JMTR at 673K to ∼0.11dpa and post-irradiation examinations were carried out on V–4Cr–4Ti (NIFS-HEAT-2) heat-treated at 1073–1373K for 1h, for the purpose of optimizing the heat treatment conditions considering the effect of neutron irradiation.After irradiation, hardness and Charpy impact properties were similar with each other at 1073–1273K, which is in strong contrast with the unirradiated V–4Cr–4Ti, which showed clearly minimum hardness and optimum impact property at 1173K. Significant hardening and an increase in DBTT occurred after irradiation, however, at 1373K. TEM observations showed similar microstructure with high density of precipitates and very low dislocation density at 1173–1273K following irradiation.The mechanism of the weak dependence of properties after irradiation for the heat treatment temperatures between 1073 and 1273 and implication of the present study to determining annealing temperature was discussed.

Rate capability of lithium intercalation into nano-porous graphitized carbons

Nano-porous graphitized carbons were successfully prepared by using mono-dispersed SiO 2 colloidal crystal as a template and mesophase pitch as a carbon source with final heat treatment temperatures (HTT) of 1000–2500 °C. Rate capability of lithium intercalation/de-intercalation of the nano-porous graphitized carbons was investigated. 35–60% of capacities were retained when the current density was increased from 37.2 mA g − 1 to 372 mA g − 1 . Electrochemical impedance spectra indicated that formation of SEI layers caused increased polarization.

Enhanced Jc of B-rich and SiC doped MgB2 tapes fabricated by a modified in-situ PIT method with two stage heat treatment

B-rich and SiC doped MgB2 tapes were fabricated by a modified in-situ PIT method with two stage heat treatment. B composition ratio and an amount of SiC doping were systematically changed. The effect of pre-heating and final heating conditions on Jc-B properties was also studied. Mean grain size of MgB2.8 specimens reduced to about 100 nm by increasing SiC doping 5.7%. In low fields Jc slightly increased for a little SiC doped specimens. On the other hand, in high fields, Jc obviously increased with increasing SiC doping. Maximum Jc reached 1.8×103 A/cm2 at 3 T, 20 K for MgB2.8 specimen doped SiC 5.7 mol%. Birr also increased with increasing SiC doping. Jc systematically increased with the decrease of temperature of pre-heat treatment. In contrast Jc systematically increased with the increase of temperature of final heat treatment. Best Jc of 8.6×104 A/cm2 at 20 K, 0 T was achieved for specimen with 700 °C for 5 hours + 800 °C for 1 hour heating. Birr tended to increase with the increase of Jc.