Role of the high-temperature synthesis of the titanium carbide phase in lowering the limits of detection of impurities in high-purity titanium dioxide

1989 ◽  
Vol 51 (5) ◽  
pp. 1129-1131
Author(s):  
I. A. Grikit ◽  
A. S. Kozhevnikova ◽  
S. N. Dotsenko ◽  
Yu. I. Rys'eva
Keyword(s):  
Titanium Dioxide ◽  
High Temperature ◽  
Titanium Carbide ◽  
High Purity ◽  
Carbide Phase ◽  
Temperature Synthesis ◽  
Limits Of Detection ◽  
High Temperature Synthesis ◽  
Purity Titanium

scholarly journals ASSESSMENT OF GERM CRITICAL DIMENSION AND CONDITIONS OF TITANIUM CARBIDE CRYSTALLINE PHASE GROWTH DURING SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS

2019 ◽  
Vol 2019 (7) ◽  
pp. 45-51
Author(s):  
Альфия Луц ◽  
Al'fiya Luc ◽  
Евгений Амосов ◽  
Evgeniy Amosov ◽  
Юлия Махонина ◽  
...  
Keyword(s):  
High Temperature ◽  
Titanium Carbide ◽  
Crystalline Phase ◽  
Carbide Phase ◽  
Critical Dimension ◽  
Exponential Dependence ◽  
Temperature Synthesis ◽  
Melt Temperature ◽  
Aluminum Melt ◽  
High Temperature Synthesis

The purpose of the work consists in the critical dimension definition of a germ and the finite quantity of a titanium carbide crystalline phase during the realization of a self-propagating high temperature synthesis in aluminum melt. For investigations there were used the following components: A7 technical aluminum (cleanness 99.7%), TPP-7 titanium powder (cleanness 97.9%), P-701 technical carbon (cleanness 99.7%), PMC-1 copper powder (cleanness 99.5%), Mn-95 manganese powder (cleanness 95%), halide salt Na2TiF6 (mass share of basic matter not less than 99.0%). A metallographic analysis was carried out with the aid of Jeol JSM-6390A raster electronic microscope. X-Ray spectrum shooting was carried out with the aid of ARL X’tr A diffractometer and with the use of Cu-radiation during continuous scanning in the range of 20 from 20 to 80 degrees at the rate of 2 degrees per minute. By results of theoretical computations of the microstructures and diffractograms analysis of the obtained samples of the composite alloy of (Al-5%Cu-2%Mn) – 10%TiC system there was revealed that: 1) germ critical dimension of the titanium carbide phase in aluminum melt was about 2 nm; 2) according to the exponential dependence of the rate of titanium carbide crystalline growth upon a temperature, at the melt temperature of 1173 K its dimension must be 50 nm; 3) calculation of particles of the titanium carbide phase according to diffractograms data with use of Sekyakov-Sherrer formula confirms their nano-dimensional level; 4) presence of the titanium carbide phase both in nano-dispersed state, and in nano-structural one results in composite stress-strain characteristics increase.

Self-Propagating High-Temperature Synthesis of Simulated 90SrO-Contained Radioactive Graphite in N2 Atmosphere

2014 ◽  
Vol 525 ◽  
pp. 45-52 ◽  
Author(s):  
Xi Rui Lu ◽  
Si Jin Su ◽  
Meng Jun Chen
Keyword(s):  
Titanium Dioxide ◽  
High Temperature ◽  
Titanium Carbide ◽  
Exothermic Reaction ◽  
The Self ◽  
Cubic Phase ◽  
Temperature Synthesis ◽  
Radioactive Graphite ◽  
Waste Forms ◽  
High Temperature Synthesis

In order to evaluate the performance of the self-propagating high-temperature synthesis (SHS) to treat 90SrO-contained radioactive graphite in N2 atmosphere, waste forms were prepared with the self-developed SHS reactor according to the waste forms formulation designed with a solid-soluted content of 010 wt% (calibrated in mass, hereinafter the same). The waste forms were made with the exothermic reaction (3C + 4Al + 3TiO2 = 2Al2O3 + 3TiC + Q), where, 88SrO (a stable Sr isotope)-containing 88SrO was used to simulate 90SrO. And the raw materials for the waste forms were the powdery materials of graphite (C), aluminum (Al) and titanium dioxide (TiO2). Then, X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used to test and analyze the phase composition and morphology of the prepared waste forms. According to the results in dealing with the treatment with the given exothermic reaction of the 90SrOcontaining radioactive graphite in N2 atmosphere, the SrO solid solubility could be up to 8 wt%. Besides, with a SrO content of 0~2 wt%, the major composition of the waste forms was including: alumina (Al2O3) in diamond scheme, titanium carbide (TiC) in cubic phase, graphite (C), anatase titanium dioxide (TiO2) and aluminum nitride (AlN) in cubic phase. Comparatively, with a SrO content of 3~8 wt%%, the major composition of the waste forms was including: alumina (Al2O3) in diamond scheme, titanium carbide (TiC) in cubic phase, graphite (C), anatase titanium dioxide (TiO2), aluminum nitride (AlN) in cubic phase and rhomboid aluminum titanate (Al2TiO5). Furthermore, diffractive peaks of unidentified phase occurred at 2θ = 7.7°, 15.6°, 19.8° and 24.1° position, whose intensities were increased with the increasing additional SrO content. The grain sizes of the prepared waste forms are mainly within 515μm, majorly exist in pieces.

Effect of Gravity on Titanium Carbide Foams by Self-propagation High-temperature Synthesis

1999 ◽  
Vol 14 (4) ◽  
pp. 1516-1523 ◽  
Author(s):  
Yasuhiro Tanabe ◽  
Takashi Sakamoto ◽  
Nobuko Okada ◽  
Takashi Akatsu ◽  
Eiichi Yasuda ◽  
...  
Keyword(s):  
High Temperature ◽  
Carbon Black ◽  
Titanium Carbide ◽  
Combustion Wave ◽  
Propagation Velocity ◽  
Temperature Synthesis ◽  
Environmental Pressures ◽  
Environmental Pressure ◽  
High Temperature Synthesis ◽  
Microgravity Conditions

Titanium carbide foams are synthesized by a self-propagation high-temperature synthesis technique using carbon black, which generates gases during the synthesis. The synthesis is performed under terrestrial and microgravity conditions. The effects of gravity on the synthesis are evaluated in this study. The foaming is mainly caused by H2O and CO gases from the carbon black. The elongation of the products increases with decreasing environmental pressure and increasing amount of generated gases. Since the gas flows out along the direction of the combustion wave propagation, the products expand only along this direction. The propagation velocity of the combustion wave increases with increasing amount of generated gases and environmental pressure, which is due to the amount of molten Ti transporting into the reaction/preheat zone. Under higher environmental pressures, thermal convection of the environmental gases mainly affects the propagation velocity. However, at lower pressures, the behavior of the molten Ti has a great effect compared with the gases surrounding the specimens.

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