Antioxidants in carbon-bearing refractories

Бамбуров, В. Г.; Sivtsova, O. V.; Semyannikov, V. P.; Киселев, В. А.

doi:10.1007/bf02693731

Cited by 4 publications

(4 citation statements)

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“…Along with TiB 2 , B 4 C, CrB 2 , BN and amorphous boron, MgB 2 was announced to be an antioxidant, i.e., an additive to carbon-containing refractory materials used in metallurgy to prevent them from breakdown upon oxidation of carbon in the surface layer. 75 Oxidation and phase formation in the mixture of MgB 2 synthesised in the reaction MgB 12 + Mg ? MgB 2 with periclase ± carbon composite have been studied as functions of temperature.…”

Section: Application Areas Of Magnesium Boridesmentioning

confidence: 99%

“…MgB 2 with periclase ± carbon composite have been studied as functions of temperature. 75 The process is characterised by exothermic effects, begins at *470 8C and results in MgO, Mg 2 B 2 O 5 and boric anhydride. Similar magnesium polyborides (mixtures of amorphous boron and MgB 12 obtained by magnesium reduction of B 2 O 3 ) were found to behave similarly.…”

Section: Application Areas Of Magnesium Boridesmentioning

confidence: 99%

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Superconducting MgB₂and related compounds: synthesis, properties and electronic structure

Ivanovskiĭ¹

2001

Russ. Chem. Rev.

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The X-ray spectrometer used in high-energy-density plasma experiments generally requires both broad X-ray energy coverage and high temporal, spatial, and spectral resolutions for overcoming the difficulties imposed by the X-ray background, debris, and mechanical shocks. By using an elliptical crystal together with a streak camera, we resolve this issue at the SG-II laser facility. The carefully designed elliptical crystal has a broad spectral coverage with high resolution, strong rejection of the diffuse and/or fluorescent background radiation, and negligible source broadening for extended sources. The spectra that are Bragg reflected (23 • < θ < 38 • ) from the crystal are focused onto a streak camera slit 18 mm long and about 80 µm wide, to obtain a time-resolved spectrum. With experimental measurements, we demonstrate that the quartz(1011) elliptical analyzer at the SG-II laser facility has a single-shot spectral range of (4.64-6.45) keV, a typical spectral resolution of E/∆E = 560, and an enhanced focusing power in the spectral dimension. For titanium (Ti) data, the lines of interest show a distribution as a function of time and the temporal variations of the He-α and Li-like Ti satellite lines and their spatial profiles show intensity peak red shifts. The spectrometer sensitivity is illustrated with a temporal resolution of better than 25 ps, which satisfies the near-term requirements of high-energy-density physics experiments.

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Section: Application Areas Of Magnesium Boridesmentioning

confidence: 99%

Section: Application Areas Of Magnesium Boridesmentioning

confidence: 99%

Superconducting MgB₂and related compounds: synthesis, properties and electronic structure

Ivanovskiĭ¹

2001

Russ. Chem. Rev.

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“…best corrosion resistance but negative effect on steel quality especially for ultra low carbon (ULC) steel qualities [5] iv) formation of interstices between magnesia grains and slag as well as gas infiltration and MgO dissolution at elevated temperatures [13][14][15] v) carbon pick up in ULC-steel processing routes. [5] In order to improve poor mechanical strength and oxidation resistance due to the presence of carbon, antioxidant additives, for example Al, [16][17][18][19][20] Ti, [18,20] Si, [17,21] SiC, [22] or Mg, combinations/alloys of these metals [23,24] and oxides, [25] carbides and boron based compounds, [26] have been added to MgO-C refractories since the 1970 s. Nevertheless in terms of reduced wear rates, no advantages have been found for the use of antioxidants. [5] Furthermore there is still the difficulty to achieve decarburization and minimization of MgO dissolution in the slag at the same time due to antioxidant additives.…”

Section: Introductionmentioning

confidence: 99%

Reinforced Cellular Carbon Matrix–MgO Composites for High Temperature Applications: Microstructural Aspects and Colloidal Processing

Silveira

Falk

2011

Adv Eng Mater

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The main potential of functionalized cellular carbon refractories is the considerable variation range of cell dimensions, cell geometries, i.e. spatial arrangement of interconnected carbon strut networks, as well as cell compositions, i.e. layered or multilayered cell conformations. In order to achieve this last goal, it will have to provide available post‐processing procedures to upgrade cellular carbon matrices for specific functions, i.e. tailored moduli of elasticity, thermal shock resistance, that cannot be technically or economically provided by conventional low carbon MgO–C refractories.1 Here we report different colloidal synthetic processing routes for tailoring reinforced cellular and reticulated glassy carbon structures in the macro‐, meso‐, and microscale, which then gives rise to very high thermal shock resistance characteristics. The cellular interconnected glassy carbon network is processed by replication of PU foams with phenolic resins and subsequent carbonization in inert atmospheres. In order to improve the water‐wettability of tailored glassy carbon cellular matrices and to ease the subsequent infiltration of aqueous MgO suspensions into open porous, cellular carbon structures a low cost YSZ, and SiC coating concept is proposed using an electrophoretic deposition (EPD) method and subsequent sintering in order to achieve the reinforcement of carbon phase, respectively. These as‐received wettable and reinforced coatings and functional layers on the interconnected cellular glassy carbon network are able to reliably allow the infiltration of aqueous MgO suspensions to build up low carbon functional C/SiC‐ as well as C/YSZ–MgO refractories with designed and controlled thermo‐mechanical properties.

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“…In order to optimize the composition of the periclase-carbon articles the Company searches for more efficient additives capable of improving the oxidation resistance and raising the stability of the lining in the slag-line area. Analysis of published data shows that boron-bearing compounds possess higher activity than aluminum when heated in an air atmosphere [3]. The compounds include titanium diboride, boron carbide, magnesium diboride, boron nitride, etc.…”

mentioning

confidence: 98%

Development of optimum composition of a batch for periclase-carbon lining of steel-teeming ladles of AFM shops

et al. 2007

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Results of a study of the effect of antioxidant additives, i.e., metallic aluminum and titanium diboride, on the quality parameters of periclase-carbon ladle refractories are presented. Laboratory studies have shown that the addition of the studied antioxidants into the batch increases the strength and lowers the porosity of the specimens. The size of the decarburized layer due to the addition of metallic aluminum and titanium diboride is virtually the same, but the use of TiB 2 adds additional strength to the decarburized and transition layers of the specimens. It is recommended that pilot tests be performed for joint introduction of the additives.A study of the mechanism of fracture of periclase-carbon refractories in contact with molten slag and metal has shown that decarburization of the functional zone affects the wear of the refractories considerably. Above 500°C the carbon component (graphite and the carbon binder) of the refractory oxidizes (burns out) and this process continues to the maximum service temperature [1]. This causes softening of the articles at 500 -900°C and increases their porosity. When the entire carbon is oxidized, the surface layer of the refractory is slagged, the periclase powder dissolves, and the contact products are washed out.In order to protect the carbon from oxidation the refractory composition is enriched with antioxidant additives in the form of fine powder, the amount of which is optimized for every kind of article; as a rule, the content of antioxidants does not exceed 5% [2]. These additives are oxidized by oxygen and by the iron oxides of the slag more rapidly, and this lowers the rate of carbon oxidation. Despite the limited proportion of antioxidant additives in the batch the former affect the properties of the refractory (oxidation, thermomechanical properties, corrosion, phase composition, etc.) quite substantially. The lining of the slag-line area of steel teeming ladles at the shop of magnesia-dolomite refractories of the "Ogneupor" Company is produced from refractories with metallic aluminum added as an antioxidant. In order to optimize the composition of the periclase-carbon articles the Company searches for more efficient additives capable of improving the oxidation resistance and raising the stability of the lining in the slag-line area. Analysis of published data shows that boron-bearing compounds possess higher activity than aluminum when heated in an air atmosphere [3]. The compounds include titanium diboride, boron carbide, magnesium diboride, boron nitride, etc. The antioxidant action of these additives is explainable by oxidation at a temperature exceeding 1300°C that yields a melt of magnesium borate (3MgO·B 3 O 3 ) and gaseous products of the reaction of oxidation of the borates (B 3 O 3 , gaseous Mg, etc.). The appearance of liquid phase promotes lowering of the open porosity and thus prevents the diffusion of oxygen into the refractory. The gases formed lower the oxygen pressure in the pores of the refractory, prevent oxidation of the graphite, diffus...

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Antioxidants in carbon-bearing refractories

Cited by 4 publications

References 1 publication

Superconducting MgB₂and related compounds: synthesis, properties and electronic structure

Superconducting MgB₂and related compounds: synthesis, properties and electronic structure

Reinforced Cellular Carbon Matrix–MgO Composites for High Temperature Applications: Microstructural Aspects and Colloidal Processing

Development of optimum composition of a batch for periclase-carbon lining of steel-teeming ladles of AFM shops

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Antioxidants in carbon-bearing refractories

Cited by 4 publications

References 1 publication

Superconducting MgB2and related compounds: synthesis, properties and electronic structure

Superconducting MgB2and related compounds: synthesis, properties and electronic structure

Reinforced Cellular Carbon Matrix–MgO Composites for High Temperature Applications: Microstructural Aspects and Colloidal Processing

Development of optimum composition of a batch for periclase-carbon lining of steel-teeming ladles of AFM shops

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Product

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Superconducting MgB₂and related compounds: synthesis, properties and electronic structure

Superconducting MgB₂and related compounds: synthesis, properties and electronic structure