Addition Of Carbon Powder Research Articles

Improving wear performance, physical, and mechanical properties of iron sand/epoxy composite modified with carbon powder

This study was conducted to investigate the usage of iron sand as composite reinforcement. The addition of carbon powder with variations of 15 wt%, 20 wt%, and 30 wt% is expected to enhance the interfacial bond between iron sand and epoxy matrix to be better. Physical and mechanical properties of the composite were investigated using a wear resistance test Pin on Disc method, shore-D hardness, bending test, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The results showed an increase in wear resistance and mechanical properties of composite due to the addition of carbon powder. This was confirmed by the fact that the HCP composite with 30 wt% carbon powder showed a good increase in wear resistance but a reduction in flexural properties and hardness values. Meanwhile, the LCP composite with 20 wt% carbon powder was recommended in terms of good flexural properties. The increased mechanical properties of composite were supported by composite crystallinity index value recorded to be 59.45 % from the XRD test. SEM analysis showed better dispersion and interfacial bonding for carbon powder and iron sand in the composite matrix. These results are expected to contribute to the new development of composite brake pad.

Study of direct alloying of steels by carbon reduction of Cr2O3 under vacuum

Currently, steel is mainly alloyed by adding ferrochrome alloys in the production of chromium-containing steels. However, the production of ferrochrome consumes a lot of electricity and produces a large number of additional products that are extremely harmful to the environment. For the consideration of the above problems, the experiment studied the reduction behavior of Cr2O3 using carbon powder as the reductant under different ambient pressures, different reductant dosages, and different initial oxygen contents in the molten steel. The results show that CO bubbles can be formed by decreasing the air pressure and increasing the amount of reductant, thus the reduction rate and reduction efficiency of Cr2O3 can be increased. It was found that the ambient air pressure mainly affected the reduction rate of Cr2O3, and the fastest reduction rate of Cr2O3 was found in vacuum environment. The reductant dosage has great influence on the reduction rate, reduction efficiency, density and size of inclusions of Cr2O3. Addition of carbon powder with a carbon-to-oxygen molar ratio of 2 will significantly improve the reduction rate of Cr2O3. The yield of [Cr] in steel can reach more than 95 %. In addition, the density of inclusions in steel is stabilized below 0.2/mm−2. The addition of carbon powder with nc:no ≤ 1.0 significantly reduces the reduction rate of Cr2O3 due to the decrease of carbon concentration in the steel. The density of inclusions in steel also increased significantly up to 210.4/mm−2. The initial oxygen content in the molten steel had little effect on the reduction of Cr2O3. However, the reduction rate of Cr2O3 is lower in steel with high oxygen concentration than in steel with low oxygen concentration. Under the optimum reduction conditions-nc:no = 2.0, initial oxygen content of 3 × 10−4, and ambient air pressure of 50 Pa. The yield of [Cr] in steel can reach 96.85 %, the total oxygen content can be reduced to 1.6 × 10−5, the density of inclusions is 0.04/mm−2, and the size of inclusions is below 1.8 μm.

Effect of carbon black powder content on thermal, physical, and mechanical properties of carbon fabric reinforced phenolic composite

Using heat-resistant fiber-reinforced phenolic composite materials (carbon fiber, glass fiber, etc.) to protect the rocket motor from high temperature has confirmed its superiority thanks to its thermal insulation and high-temperature resistance. The improvement of thermal protection properties of materials to diversify the thermal protection material family is a growing trend. Accordingly, this paper focuses on determining the influence of the percentage of carbon nano powder (0-14%) on the thermal, physical and mechanical properties of carbon fiber/phenolic matrix composite (CPC) in order to find out the extent of reasonable proportion of carbon powder to improve thermal protection. The results indicated that the addition of carbon powder with a content of about 6–10% significantly improved the thermal protection efficiency of CPC materials. The determined thermophysical parameters are the basis for calculating and designing of solid rocket motor heat insulation layer.

Investigation of Microwave Sintering of B-Type Carbonated Hydroxyapatite Bioceramics

B-type carbonated hydroxyapatite (CBHA) is potentially an excellent biodegradable bioceramic for bone repair. However, conventional sintering results in formation of undesired phases. Therefore, microwave sintering of CBHA was investigated to assess the possibility to reduce formation of unwanted phases. Pellets with 0.8 mol% of B-type carbonate were sintered in a multimode instrumented cavity under static air with short thermal cycles. They were prepared from a CBHA powder alone and from a mixture of CBHA and carbon powder to generate a local in-situ CO2 atmosphere. XRD, FT-IR, SEM and BET analyses indicated that CBHA densification with increase temperature lead to decomposition into apatite. The addition of carbon powder to the CBHA that generate a CO2-rich atmosphere around the samples did not prevent the decomposition. Efficient control of temperature and atmosphere composition is required to improve microwave sintering of CBHA bioceramics.

Fe7S8/FeS2/C as an efficient catalyst for electrocatalytic water splitting

Exploring effective bi-functional catalysts is of great significance to enhance the electrochemical activity for overall water splitting. To date, Fe7S8 has been rarely reported to realize electrochemical overall water splitting because of its intrinsic poor conductivity. In this paper, Fe7S8/FeS2 heterostructured nanosheets with interface structures and defect sites are prepared via a facile hydrothermal method. Fe7S8/FeS2/C electrocatalysts are constructed through the addition of carbon powder to weaken the electron transfer barrier. As expected, Fe7S8/FeS2/C requires the overpotential of 262 mV and 198 mV to reach 10 mA/cm2 toward oxygen evolution reaction and hydrogen evolution reaction, respectively. Moreover, Fe7S8/FeS2/C attains a voltage of 1.67 V at 10 mA/cm2 and maintains long-term stability for 24 h toward overall water splitting in a two-electrode system. The excellent activity can be related to interface structures and surface defect sites, which boost the charge transfer rate owing to the rich active sites.

Development of Paper Actuators Based on Carbon-Nanotube-Composite Paper.

We propose a unique soft actuator—a paper actuator—based on carbon-nanotube-composite paper (CNT-composite paper), which is a composite of carbon nanotubes (CNTs) and paper. CNT-composite paper has highly efficient properties because of the contained CNTs, such as high electrical conductivity and semiconducting properties. We are considering using CNT-composite paper for various devices. In this study, we successfully developed a paper actuator. We determined the structure of the paper actuator by referencing that of bucky-gel actuators. The actuator operates using the force generated by the movement of ions. In addition to making the paper actuator, we also attempted to improve its performance, using pressure as an index and an electronic scale to measure the pressure. We investigated the optimal dispersant for use in paper actuators, expecting the residual dispersant on the CNT-composite paper to affect the performance differently depending on the type of dispersant. Referring to research on bucky-gel actuators, we also found that the addition of carbon powder to the electrode layers is effective in improving the pressure for paper actuators. We believe that the paper actuator could be used in various situations due to its ease of processing.

Performance comparison with different methods for ethanol/O2 biofuel cell based on NAD+ cofactor immobilized and activated by two types of carbon nanoparticles

Biofuel cells are an attractive alternative to conventional fuel cells, because they use biological catalysts. We report in this article the construction of an ethanol/O2 enzymatic biofuel cell. In the first time, the performance comparison with different methods for ethanol/O2 biofuel cell has been study. Alcohol dehydrogenase, a nicotinamide adenine dinucleotide (NAD)-dependent enzyme, is immobilized with NAD+, diaphorase, and vitamin K3 (VK3) on the electrode. The oxygen is reduced at the cathode with laccase and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS). The performances of the electrodes are improved thanks to addition of carbon powder (KS6 and Super P® carbon). The benefit of the carbon particles with higher surface porosity was explained by the high-porous structure that offered a closer proximity to the reactive species and improved diffusion of ethanol and oxygen within the enzyme films. Efficiency of immobilization of NAD+ cofactor has been also demonstrated. We have shown the effect of multi-enzymatic reaction at the anode on the storage and operational stability. A high open-circuit potential has been recorded 1.02 V, demonstrating the benefit of NAD+ immobilization with maximal power density of 300 μW cm−2. Chronoamperometric measurements show a current density of 90 μA cm−2 during 20 h demonstrating the operational stability of the ethanol biofuel cell based on NAD+ cofactor immobilization.

Carbon and oxygen behavior in the RH degasser with carbon powder addition

for ultra-low-carbon (ULC) steel production, the higher oxygen content before Ruhrstahl-Heraeus (RH) decarburization (de-C) treatment could shorten the de-C time in the RH degasser. However, this would lead to oxidation rates being exceeded by molten steel production, affecting ULC steel surface quality. In this work, a carbon powder addition (CPA) process was proposed to reduce the dissolved oxygen content at the end of RH de-C through addition of carbon powder to molten steel in the vacuum vessel. Carbon and oxygen behavior during the CPA and conventional process was then studied. The results demonstrated that the de-C rate with CPA was lower compared to the conventional process, but the carbon content at the end of de-C presented no difference. The de-C reaction for CPA process took place in the four reaction sites: (1) within the bulk steel where the spontaneous CO bubbles form; (2) splashing area on the liquid steel surface; (3) Ar bubble surface; (4) molten steel surface. The CPA process could significantly reduce the dissolved oxygen content at the end of de-C, the sum content of FeO and MnO in the slag, the aluminum consumption, and the defect rate of rolled products. This was beneficial in improving ULC steel cleanliness.

Thermal Conductivity Enhancement of Phase Change Materials for Low-Temperature Thermal Energy Storage Applications

Low thermal conductivity is the main drawback of phase change materials (PCMs) that is yet to be fully addressed. This paper studies several efficient, cost-effective, and easy-to-use experimental techniques to enhance thermal conductivity of an organic phase change material used for low-temperature thermal energy storage applications. In such applications, the challenges associated with low thermal conductivity of such organic PCMs are even more pronounced. In this investigation, polyethylene glycol (PEG-1000) is used as PCM. To improve the thermal conductivity of the selected PCM, three techniques including addition of carbon powder, and application of aluminum and graphite fins, are utilized. For measurement of thermal conductivity, two experimental methods—including flat and cylindrical configurations—are devised and increments in thermal conductivity are calculated. Melting and solidification processes are analyzed to evaluate melting and solidification zones, and temperature ranges for melting and solidification processes respectively. Furthermore, latent heat of melting is computed under constant values of heat load. Ultimately, specific heat of the PCM in solid state is measured by calorimetry method considering water and methanol as calorimeter fluids. Based on the results, the fin stack can enhance the effective thermal conductivity by more than 40 times with aluminum fins and 33 times with carbon fins. For pure PCM sample, Initiation of melting takes place around 37 °C and continues to above 40 °C depending on input heat load; and solidification temperature range was found to be 33.6–34.9 °C. The investigation will provide a twofold pathway, one to enhance thermal conductivity of PCMs, and secondly ‘relatively easy to set-up’ methods to measure properties of pure and enhanced PCMs.

Reduction of chromium ore by recycled silicon cutting sludge waste with carbon addition

A basic study on the feasibility of producing ferrochrome (silicon) alloys using Si sludge waste collected from the silicon ingot cutting process was carried out, and the effects of the addition of carbon components, reaction time, and reaction temperature on the silicothermic reduction of chromium ore by Si sludge were studied. The cordierite (Mg2Al4Si5O18) phase was generated in the slag, and the Fe–Cr(–Si)–C alloy was formed by the silicothermic reduction. Moreover, the addition of carbon powder lowered the reduction initiating temperature, and the reduction ratio based on the oxygen content was evaluated at around 68–88% at 1573 K, which increased with an increase in carbon. However, it was difficult to find a significant difference in the reduction behavior in response to increasing the holding time. The reduced ferrochrome (Fe–Cr) metal alloy droplets coalesced more intensively with an increase in reduction temperature, and for manufacturing the Fe–Cr alloy, it is estimated that a temperature of 1773 K or higher is required for good separation of the slag and the metal. Furthermore, the metallization ratio was defined, and higher values are evaluated for Fe than for Cr.

Planar Mesoporous Silicon Flakes with Microns Thicknesses As an Anode Material for Li-Ion Batteries: Fabrication, Characterization and Electrochemical Tests

Conventional Li-ion batteries based on a graphite anode with any of Li-Co-(Mn, etc)-oxides cathodes and liquid electrolytes have small specific capacities due to low theoretical capacity of carbon that is of app. 372mAhs/g. Recent research revealed many new perspective materials for using instead of a carbon anode [1] and silicon is one of the best with a theoretical capacity of nearly 4200mAhs/g [2]. This emerging material has been extensively studied in a number of its structural forms, beginning from a simple planar Si wafer to more sophisticated nano-structures embedded into a Si support (wafer) or even as free standing nano-powders of different shapes and geometry, for review see [3]. In this work we studied nano-structured silicon material in form of planar mesoporous flakes with microns thicknesses in an attempt to adjust such Si powder for using it as an anode in Li-ion battery. We report here a fabrication process based on electrochemical etching of Si-wafer in a special regime that allowed not only a formation of meso pores in bulk Si but also a separation of nanostructured material into planar flakes with microns thicknesses and a collection of a final Si powder. We performed an additional coverage of an obtained material with carbon to improve electrical conductivity of the powder. Then we widely characterized both nanostructured materials to know its surface chemical compositions, internal surface areas, pore size distributions and how the performed carbon coating influenced on them. Finally, we prepared anode masses with more then 85% of silicon using standard battery powder technology with conventional binder, solvent and addition of carbon powder. A battery with Li metal as contra electrode was assembled and electrochemical tests fulfilled. Used materials, chemicals and methods: To obtain the nanostructured Si-powder the p+ doped Si wafer of 0.01-0.02 Ohm cm resistivity, 1500 microns thickness and 4cm diameter was used. The electrochemical cell provided the 12.5cm2 area for etching. 100ml of the 1:2 HF (45% conc.):EtOH electrolyte was employed to perform the anodic treatment of a wafer up to 300mkm in-depth in total. The electrochemical regime consisted in application of two anodic steps of different intensity (J1=50mA/cm2; J2=100mA/cm2) and duration (t1=600s; t2=10s) followed by a 20s time interval with zero current for relaxation of a system. This regime was subsequently applied in several cycles (up to 10) without opening the cell and an average depth in a cycle reached app.20mkm. Detailed description of similar regimes is reported elsewhere [4]. After performing all the programmed cycles, the last intensive current (more than 150mA/cm2) was applied for 20s to cut off the obtained mesoporous Si layers (future flakes) from the Si wafer. At this moment all the material was packed together that permitted its exhaustive washing with water and ethanol. Initial crashing of the layers into flakes was done in the laboratory ultrasound bath and the powder was collected into ethanol suspension. After evaporation of solvent at 50oC and additional milling of flakes in the Agatha mortar the dry material was obtained. The carbon coverage was effectuated in the 1:1 acetylene + argon atmosphere at a total gas flow of 0.5L/min and temperature of 850oC during 15 minutes, as described in [5]. Both covered and pristine mesoporous silicon materials were used for preparation of the anodes for battery tests. The weight ratio 85:7:8 between the meso-porous silicon powder, the 15% PVdF binder dissolved in NMP and the C black powder was used for preparation of the anodic masses. The electrochemical examination of the silicon electrodes was performed in double-electrode coin cells CR2032 by using a CT-3008W-5V10 mA battery testing system (Neware). Lithium metal served as the counter electrode. The electrolyte consisted of 1M LiPF6 in a solution mixture of EC/PC/DEC/EMC/PA (ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl-methyl carbonate, propyl acetate) (TC-E810 Tinci).

Synthesis and characterization of AlMgB14 hot pressed under different environments

AlMgB14 hot pressed under different environments from the elemental powders was investigated. The microstructure of the products was analyzed by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and X-ray diffractometer (XRD). The density, hardness and fracture toughness of AlMgB14 were also examined. The results show that single phase of MgAl2O4 is formed in hot pressed Al-Mg-B system in air. The addition of carbon powder cannot reduce the formation of MgAl2O4. Additional Al (10 wt.%) and Mg (10 wt.%) can effectively compensate for their loss in the formation of MgAl2O4 and enhance the production of AlMgB14 under agron atmosphere. The AlMgB14 with 10 vol.% spinel MgAl2O4 owns a hardness of 28.42 GPa and a fracture toughness of 2.92 MPa?m1/2.

Study on the Properties of Coffee Carbon Filament Yarns

Coffee carbon fiber is a kind of functional polyester fiber. Waste coffee grounds is milled into nanometer powder and then added to the polyester spinning fluid. Coffee carbon filament yarns have the functions of antibacterial deodorant, sending anion, and thermal insulation. In this paper, the morphology and properties of coffee carbon filament yarns were tested, such as scanning electron microscopy, tensile, moisture regain and cohesion. Polyethylene terephthalate filament yarns were selected for comparison with coffee carbon yarns. The results show that coffee carbon powder is distributed both on the surface and inside of filament yarns; the moisture regain of coffee carbon filament yarns is higher than that of PET yarns; the strength and elongation of coffee carbon filament yarns and of PET filament yarns is close; the boiling water shrinkage of coffee carbon filament yarns is lower than that of PET filament yarns; the addition of carbon powder can not reduce the cohesion of coffee carbon filament yarns.

Surface study of the building steps of enzymatic sol–gel biosensors at the micro- and nano-scales

We have studied, by scanning electron and atomic force (AFM) microscopies, how each step involved in the building process of massive carbon-based sol–gel enzymatic biosensors changes and determines the resulting surface morphology and nano-mechanical properties. The biosensor, selected as a model, is developed by the entrapment of glucose oxidase (GOx), a redox mediator and a material conferring conductivity (graphite powder, C) into a polymeric tridimensional network generated by sol–gel technology using tetraethoxysilane (TEOS) as precursor. The smooth TEOS morphology is formed by an irregular nanoporous network, which is very adequate for enzyme encapsulation. Upon addition of carbon powder to the system (TEOS/C), the surface morphology changes but it is still rather irregular since carbon powder micro-grains are found scattered on it. This morphology results in a rather rough surface at the micro- scale whereas at the nano- scale both atomically flat graphitic and nanoporous TEOS domains are found. In contrast, the final biosensing device surface is quite homogeneous and composed by flat platelets separated by deep crevices. On top of most of these platelets there is a soft, as assessed by AFM force indentation experiments, layer of globular structures whose dimensions are compatible with GOx molecules. The final device surface architecture results to be open and accessible both at the micro and nano scales, which turns it as adequate to enhance both the accessibility of the analytes to entrapped proteins and the mass-transfer rates. Finally, in order to show the applicability of the studied biosensor, its response was evaluated towards varying glucose concentrations, displaying a clear electrocatalytic activity.

Characterization and recycling of cadmium from waste nickel–cadmium batteries

A severe threat was posed due to improper and inefficient recycling of waste batteries in China. The present work considered the fundamental aspects of the recycling of cadmium from waste nickel–cadmium batteries by means of vacuum metallurgy separation in scale-up. In the first stage of this work, the characterization of waste nickel–cadmium batteries was carried out. Five types of batteries from different brands and models were selected and their components were characterized in relation to their elemental chemical composition and main phase. In the second stage of this work, the parameters affecting the recycling of cadmium by means of vacuum metallurgy separation were investigated and a L 16 (4 4) orthogonal design was applied to optimize the parameters. With the thermodynamics theory and numerical analysis, it can be seen that the orthogonal design is an effective tool for investigating the parameters affecting the recycling of cadmium. The optimum operating parameters for the recycling of cadmium obtained by orthogonal design and verification test were 1073 K (temperature), 2.5 h (heating time), 2 wt.% (the addition of carbon powder), and 30 mm (the loaded height), respectively, with recycling efficiency approaching 99.98%. The XRD and ICP-AES analyzed results show that the condensed product was characterized as metallic cadmium, and cadmium purity was 99.99% under the optimum condition.

Effects of starting composition and carbon content on the formation of Ca-.ALPHA. SiAlON powders by carbothermal reduction-nitridation

Ca-α SiAlON powders were prepared at different starting compositions and carbon contents at 1450°C for 2 h in N2 from mixtures of SiO2, Al2O3, CaCO3 and carbon powders by carbothermal reduction–nitridation. Crystalline phases and particle morphology of the products were investigated. With increasing the x value in nominal Ca-α SiAlON compositions CaxSi12−3xAl3xOxN16−x, the number of small hollow spheres decreased and the size of primary grains consisting of the hollow spheres increased. The addition of carbon powder to more than 1.2 times of the necessary stoichiometric value was required to form Ca-α SiAlON hollow spheres composed of ultrafine grains.

A Novel Process for Recovering Valuable Metals from Waste Nickel−Cadmium Batteries

The environment is seriously polluted due to improper and inefficient recycling of waste nickel-cadmium (Ni-Cd) batteries in China. The aim of this work is aimed to seek an environmentally friendly recycling process for resolving the negative impacts on environmental and human health resulting from waste Ni-Cd batteries. This work investigates the fundamentals of waste Ni-Cd batteries recycling through vacuum metallurgy separation (VMS) and magnetic separation (MS). The results obtained demonstrate that the optimal temperature, the addition of carbon powder, and heating time in VMS are 1023 K, 1 wt %, 1.5 h, respectively. More than 99.2 wt % Cd is recovered under the optimal experimental condition, and the Cd purity is 99.98%. Around 98.0 wt % ferromagnetic materials are recovered through MS under 60 rpm rotational speed and the recovery ratios of Fe, Ni and Co are 99.2 wt %, 96.1 wt %, and 86.4 wt %, respectively. The composition of ferromagnetic fractions in the residue after VMS increases from 82.3 to 99.6%. Based on these results, a process (including dismantling and crushing, VMS and MS) for recycling of waste Ni-Cd batteries is proposed. This novel process provides a possibility for recycling waste Ni-Cd batteries in a large industrial scale.

Sensitivity of a Glassy Carbon Electrode Covered with a Chitin Film Improved by the Addition of Carbon Powder

The redox activity of a chitin film on a glassy carbon electrode was remarkably improved by the addition of carbon powder to the film in the detection of ascorbic acid, flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide (NADH). Although oxidation of ascorbic acid using the electrode with the chitin film did not give an appreciable voltametric response, the addition of carbon powder to the film greatly improved its activity up to a 95% level of the bare carbon electrode. For FAD and NADH, an increase in each oxidation peak was observed in a similar manner. The improvement was due to electron mediation of the carbon powder contained in the film. Thus, the electrode effectively recovers the sensitivity for some biological molecules, and thus becomes a powerful device to monitor reactions between biological molecules. Because both carbon and chitin are materials with high biocompatibility, the film can be considered as cell scaffolds. Furthermore, the film immobilized on the plate has a possibility as an electrode in itself.

304 및 316L 스테인레스강 미립 분말의 소결 특성

<TEX>$5{\sim}150{\mu}m$</TEX>의 오스테나이트계 304(Fe-18%Cr-12%Ni) 및 316L(Fe-18%Cr-13%Ni-2.4%Mo)미립 분말을 사용하여 소결 특성을 평가한 결과, 다음과 같은 결론을 얻었다 (1) 3.6ks의 소결 시간으로는 어느 경우에 있어서나 소결조건에 관계없이 소결체의 상대밀도는 <TEX>$95{\sim}98%$</TEX>에서 포화하여 완전 치밀화된 소결체를 얻을 수 없었다. (2) <TEX>$5{\mu}m$</TEX>분말을 진공소결 하였을 경우, ts=57.6ks에서 거의 완전 치밀화된 소결체가 얻어졌다. (3) 소결 분위기에 상관없이 304 및 316L소결체에는 <TEX>$0.5{\sim}0.6%$</TEX>정도의 산소가 잔류하였다. (4) 진공 소결의 경우, 탄소분 첨가에 의해 소결체의 잔류 산소량은 무첨가 소결체에 비하여 0.375이상 감소하였고, 조직적으로도 산화물은 거의 관찰되지 않았다. 또한 탄소 첨가는 소결체의 밀도 향상 효과로 작용하여 목적하는 완전 치밀화된 고성능 소결체를 제조하는 것이 가능하게 되었다. The characteristics of 304 (Fe-18%Cr-12%Ni) and 316L (Fe-18%Cr-13%Ni-2.4%Mo) austenite stainless-steel compacts sintered with <TEX>$5{\sim}15{\mu}m$</TEX> powder were investigated and the results led to the following conclusions: (1) When the sintering time was 3.6ks, the relative density of sintered compacts was <TEX>$95{\sim}98%$</TEX>, regardless of any other sintering condition. (2) When a vacuum sintering was done with <TEX>$5{\mu}m$</TEX> stainless steel powders, almost fully-dense sintered compacts were obtained at is = 57.6ks. (3) The amount of residual oxygen in 304 and 316L sintered compacts was <TEX>$0.5{\sim}0.6%$</TEX>, regardless of sintering atmosphere. (4) The amount of residual oxygen in the vacuum sintered compact decreased more than 0.3 % due to addition of carbon powder, thereby reducing the formation of oxides. Furthermore, the addition of carbon improved the density of sintered compact, which enables us to make a fully-dense high performance sintered compact.

The effect of carbon powder addition on the properties of hematite radiation shielding concrete

Carbon powder was added to shielding concrete made of Hematite aggregates to investigate its effects on shielding properties. The powder was added in different percentages, and the mechanical and radiation attenuation properties of the prepared concretes were determined. It was found that, the addition of carbon powder by 6% (by wt.) of the concrete could increase the strength on concrete by about 15%. The shielding effectiveness decreased for both gamma and neutrons with the increasing carbon powder percentage. But the loss in shielding effectiveness for both gamma rays and neutrons were within measurements error range for carbon powder addition of 6%. Simulation for the experimental measurements was carried out using Monte Carlo MCNP code, to understand the effect of carbon powder on the shielding effectiveness against neutrons. The results of the simulation were in good agreement with the experimental results.