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Aponchuk A. V., Karpov I. K., Katkov O. M. Temperature Dependence of the Composition-Paragenesis Triangular Diagram for the System Aluminum-Oxygen-Carbon // Dokl. Akad. Nauk SSSR. - 1987. - 294(5). - 1200-1202 (Russian).
[no abstract]
Aponchuk A. V., Katkov O. M., Karpov I. K. Thermodynamic Properties of Aluminum Spinel and Aluminum Oxycarbides // Izv. Vyssh. Uchebn.Zaved., Tsvetn. Metall. - 1986. - 6. - 50-53. (Russian).
[no abstract]
Behrens R. G., Rinehart G. H. Vaporization Thermodynamics and Enthalpy of Formation of Aluminum Silicon Carbide // J. Am. Ceram. Soc. - 1984. - 67(8). - 575-578.
The vaporization thermodynamics of aluminum silicon carbide was investigated using Knudsen effusion mass spectrometry. Vaporization occured incongruently to give Al(g), SiC(s), and grphite as reaction products. The vapor pressure of aluminum above (Al4SiC4 +SiC + C) was measured using graphite effusion cells with orifice areas between 1.1 X 10-2 and 3.9 X 10-4 cm2. The vapor pressure of aluminum obtained between 1427 and 1784 K using an effusion cell with the smallest orifice area, 3.9 X 10-4 cm2, is expressed as
log p (Pa) = -(18567 ± 86) (K / T) + (12.143 ± 0.054)
The third-law calculation of the enthalpy change for the reaction
Al4SiC4(s) = 4Al(g) + SiC(hex) + 3C(s)
using the presrnt aluminum pressures gives DH°(298.15 K) = (1455 ± 79) kJ·mol-1. The corresponding second-law result is DH°(298.15 K) = (1456 ± 47) kJ·mol-1. The standard enthalpy of formation of Al4SiC4(s) from the elements calculated from the present vaporization enthalpy (third-law calculation) and the enthalpies of formation of Al(g) and hexagonal SiC is DHf°(298.15 K) = -(221 ± 85) kJ·mol-1. The standard enthalpy of formation of Al4SiC4(s) from its constituent carbides Al4C3(s) and SiC(s, hex) is calculated to be DH°(298.15 K) = (38 ± 92) kJ·mol-1.
Beyer R. P., Johnson E. A. Heat Capacity of Aluminum Silicon Carbide (Al4SiC4) from 5.26 to 1047 K // J. Chem. Termodynamics. - 1984. - 16. - 1025-1029.
The molar heat capacity of aluminum silicon carbide (Al4SiC4) was measured at the Bureau of Mines from 5.26 to 301.5 K by adiabatic calorimetry and from 347 to 1047 K by differential scanning calorimetry. The values at T = 298.15 K for C°p, m , {S°m(T)-S°m(0)}, -{G°m(T)-H°m(0)}/T, and {H°m(T) - H°m(0)}are 145.07, 107.62, 40.66 J·K-1·mol-1, and 19.96 kJ·mol-1, respectively. These properties are also reported from 5 to 2000 K at convenient temperature intervals. The stendard molar enthalpy of formation DfH°m(Al4SiC4), calculated from Behrens and Rinehart's Knudsen-effusion mass-spectrometric results, is -(203.3 ± 4.9) kJ·mol-1 at 298.15 K.
Chunikhina L. L., Guzei L. S., Sokolovskaya E. M., Malov V. S. Interaction of Titanium Alloys with Carbon-Containing Materials / Splavy Titana Osobymi Svoistvami. - Nauka: Moscow, 1982. - 156-158 (Russian).
The <alpha >+<beta>- Ti alloys were reinforced with SiC fibers precoated with C or C + TiC. The Ti matrix was prealloyed with Zr 0-13, Mo 1-8, or Al 0-8%. The composite stability was evaluated at 600-800 or 1200°, and was related to compound formation in the Ti-Si-C ternary system. The phase interaction was assocd. mainly with the diffusion of C, Si, Ti, and Zr. The interphase products included Ti3Si, Ti5Si3, TiC0.96, Ti3SiC2, Ti3-xZrxSi, and (Ti, Zr)5Si3.
Fujishige M., Dokiya M., Yokokawa H., Kameyama T., Ujiie S., Motoe A., Osada K., Fukuda K. Aluminum Production by Blast Furnace Process. I. X-Ray Powder Diffraction Data for Two Hexagonal Aluminum Monoxycarbide Phases // J. Nat. Chem. Labor. Ind. - 1982. - 77. - 325-329. (Japanese).
Aluminum monoxycarbide formed when Al2O3 is reduced by carbon in the presence of Si3N4 give two X-ray diffraction profiles. The high-temperature phase exhibits the normal 2H wurtzite-type pattern, whereas the low-temperature phase produces three major lines in addition to the 2H profile. Interplanar spacings and lattice dimensions are reported, both phases can be regarded as solid solutions with AlN and / or SiC. It is suggested that the -Al4SiC4 reported by Barczak may have been a mixture of these monoxycarbides.
Goto T., Hirai T. Chemically Vapor Deposited Ti3SiC2 // Mater. Res. Bull. -1987. - 22(9). - 1195-1201.
Monolithic Ti3SiC2 polycryst. plates 40 mm .times. 12 mm .times. 0.4 mm were prepd. by chem. vapor deposition using SiCl4, TiCl4, CCl4 and H2 as source gases at a deposition rate of 200 mm/h. Crystals are hexagonal, space group P63/mmc, with a = 3.064 A and c = 17.650 A dcalcd = 4.531 and dexptl = 4.53. The (110) plane was preferably oriented parallel to the deposition surface. The Vickers microhardness decreased from 1300 to 600 kg/mm2 while increasing the indenter load from 10 to 100 g. In the 100 g to 1 kg load range, the Vickers microhardness had a const. value of ~600 kg/mm2, and many slip lines caused by the plastic deformation were obsd. X-ray powder diffraction data are given.
Goto T., Hirai T. Preparation of Silicon Carbide - Titanium Carbide In-situ Composites by Chemical Vapor Deposition / Proc. Int. Conf. Chem. Vapor Deposition, 10th. - 1987. - 1070-1079.
[no abstract]
Huang J.-L., Hurford A. C., Cutler R. A., Virkar A. V. Sintering Behaviour and Properties of SiCAlON Ceramics // J. Mater. Sci. - 1986. - 21. - 1448-1456.
Silicon carbide (SiC), aluminum oxycarbide (Al2OC), and aluminum nitride (AlN) all have the same wurtzite crystal structure and can be processed so as to form SiCAlON, an acronym for the solid solution. This paper describes processing of SiC-Al2OC ceramics by pressureless reactive sintering and gives mechanical property data on the same. Experiments showed that densification occured by a liquid-phase sintering mechanism. Both alpha and beta SiC up to a particle size of 5 mm were used to form the solid solution, boron additions were not necessary to promote densification, and densities greater than 97% of the theoretical were achieved by pressureless sintering. SiC-Al2OC ceramics, containing minor amounts of AlN, were fabricated from conventional raw materials. Phase identification by X-ray diffraction and metallography showed that the materials consisted of two phases SiCAlON and SiC. Mechanical property data were obtained on pressureless sintered and hot-pressed materials. Hot-pressed materials had room-temperature strengths in excess of 600 MPa, hardness greater than 25 GPa, and fracture toughness greater than 4 MPa·m-1/2. Pressureless sintered bars had bend strengths in excess of 300 MPa.
Inoue Z., Inomata Y., Tanaka H., Kawabata H. A New Phase of Aluminum Silicon Carbide, Al4Si2C5 // J. Mater. Sci. Lett. - 1980. - 15. - 255-256.
[no abstract]
Inoue Z., Inomata Y., Tanaka H., Kawabata H. X-ray Crystallographic Data on Aluminum Silicon Carbide, <alpha>-Al4SiC4 and Al4Si2C5 // J. Mater. Sci. - 1980. - 15. - 575-580.
Single-crystal and powder X-ray crystallographic data on <alpha>-Al4SiC4 and Al4Si2C5 are given, and their respective space groups are P63mc and R-3m. Powder X-ray diffraction lines are individually indexed in the 2<theta>-range from 5° to 110°. The unit cell dimensions obtained from a least-square computer program are a = 3.2771 A (± 0.0001 A), c = 21.676 A (± 0.002 A) for <alpha>-Al4SiC4 and a = 3.2512 A (± 0.0002 A), c = 40.1078 A (± 0.0027 A) for Al4Si2C5. In addition, it is proposed that the crystal structures of <alpha>-Al4SiC4 and Al4Si2C5 may be formed by substituting SiC-layers for AlN-layers in the Al5C3N and AI6C3N2 structures.
Iseki T., Yano T., Chung Y. S. Wetting and Properties of Reaction Products in Active Metal Brazing of Silicon Carbide // Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi. - 1989. - 97(7). - 710-714.
The joining of SiC ceramics by active metal brazing was studied. Sintered bodies of TiC, Ti5Si3, and Ti3SiC2, which have been reported to be the reaction products between SiC and active metal Ti, were fabricated. Some properties for these products, i.e. microhardness, 4-point bending strength, and thermal expansion coeff. were studied. Their effects on the joining strength are discussed. The formation of Ti5Si3 is thought to be undesirable as a reaction product due to its weakness, and the large difference of thermal expansion coeffs. between the reaction products and SiC, which means that the thicker the reaction layer grows, the larger the residual thermal stress develops. Some possibilities for the good wettability of Ag-Cu-2%Ti braze to SiC are discussed, while Ag-Cu braze did not wet. The wetting behavior of Ag-Cu and Ag-Cu-2%Ti alloys on SiC and the reaction products mentioned above was studied by the sessile drop method. Variations of their contact angles as a function of temp. were obsd., which showed the same behaviors on SiC and the reaction products, resp. These results are thought to mean that the phenomenon that Ti promotes the wetting of Ag-Cu-2%Ti alloy on SiC does not depend on reaction products, but on adsorption.
Jackson T. B., Hurford A. C., Bruner S. L., Cutler R. A. Silicon Carbide-Based Ceramics with Improved Strength // Ceram. Trans. - 1989. - 2. - 227-240.
[no abstract]
Katkov O. M., Nuykin Yu. L., Karpov I. K. Investigation of Alumina and Silica Reduction Mechanism by Simulating of Process on the Computer // Izv. Vyssh. Uchebn. Zaved., Tsvetn. Metall. - 1982. - 5. - 37-41. (Russian).
[no abstract]
Klug F. J., Pasco W. D., Borom M. P. Microstructure Development of Aluminum Oxide:Graphite Mixture During Carbothermic Reduction // J. Am. Ceram. Soc. - 1982. - 65(12). - 619-624.
Reactions in system Al-O-C are discussed. Reaction conditions which produce an -alumina body having a <70%-danse bulk region coated with an impervious, ~100-micrometer thick surface layer are described. The development of the unique composite microstructure is attributed to reactions which serve to coarsen internal grains by vapor-phase transport of volatile aluminum suboxides and, thereby, reduce firing shrinkage. Proper control of the furnace atmosphere is necessary to produce the thin, dense surface layer. The effect of varying the carbon / alumina molar ratio on linear firing shrinkage, fired density, and weight loss was examined. In addition, the effect of oxygen partial pressure on the oxidation of carbon and the formation of an intermediate reaction product, Al4O4C, was examined.
Kuo S.-Y., Jou Z. C., Virkar A. V., Rafaniello W. Fabrication, Thermal Treatment and Microstructure Development in SiC - AlN - Al2OC Ceramics // J. Mater. Sci. - 1986. - 21. - 3019-3024.
Samples containing equimolar amounts of SiC, AlN and Al2OC were fabricated by hot pressing a mixture of SiC, AlN, Al2O3 and Al4C3. The predominant constituent in the hot pressed material was of 2H crystal type. The samples were subsequently annealed at a temperature up to 2050°C for up to 153 h in an atmosphere of nitrogen. Samples made with Ibigawa <beta>-SiC exhibited formation of needle-type precipitates. Carbon deficient specimens contained substantial amounts of Al3O3N. Principal characterization techniques employed consisted of optical microscopy, electron microscopy, X-ray diffraction and chemical analysis.
Kuo S.-Y., Virkar A. V. Phase Equilibria and Phase Transformation in the Aluminum Nitride - Aluminum Oxycarbide Pseudobinary System // J. Am. Ceram. Soc. - 1989. - 72(4). - 540-550.
Samples in the pseudobinary AlN-Al2OC were fabricated by hot pressing mixtures of AlN, Al4C3, and Al2O3 powders in graphite dies in an atmosphere of nitrogen. The resulting dense samples were subjected to thermal treatments over a range of temperatures from 1550° to 1950°C. The hot-pressed as well as annealed samples were examined using optical microscopy, scanning transmission electron microscopy, and X-ray diffraction. An electron microprobe was used to determine composition. X-ray diffraction showed that Al2OC dissolved in AlN up to 44 mol% at 1800°C. Thermal treatment at lower temperatures led to the decomposition of the solid solution into two isostructural phases. In samples containing ~14 to 60 mol% AlN, the morphology of the precipitates was lenticular. Diffraction contrast analysis showed that the precipitates were rich in AlN. Lattice images showed that the (001) planes of the 2H structure were continuous between the matrix and the precipitates. These precipitates appear to be similar to Guinier-Preston zones observed in metallic alloys. When annealed for long periods of time, interface dislocations formed, signifying partial loss of coherency. In some compositions (~61 to 64 mol% AlN), a lamellar microstructure developed similar to that observed in cellular phase separation. Also, in some of compositions, an additional phase was observed whose composition and structure were not determined.

Larrère Y., Willer B., Lihrmann J.-M., Daire M. Diagrammes d'équilibre stable et métastable dans le système Al2O3 - Al4C3 // Rev. Int. Hautes Temper. Refract. Fr. - 1984. - 21. - 3-18. (French).
Stable and metastable phase-equilibrium diagrams in the Al2O3-Al4C3 binary system. The phase-equilibrium diagram describing the binary system Al2O3-Al4C3 and including a eutectic Al2O3-Al4O4C and an incongruently melting compound Al2OC which is stable at room temperature, was first established in 1956. It has to reviewed and modified owing to the existence of a critical temperature at which Al2OC decomposes into Al4O4C and Al4C3. Moreover, a metastable diagram which lowers the Al2O3-Al4C3 eutectic melting point, and which contains no more Al4O4C has to be considered. Solidification in either system depends both on the heating process of the row materials mixtures and the rate of cooling. Cristallographic and micrographic phase transformations following transition from metastable to stable diagrams have been studied.
Lihrmann J.-M., Zambetakis T., Daire M. Aluminum Monooxycarbide Al2OC in the system Si-C-Al-O-N: Some Thermodynamic Properties / Euro-Ceramics, Conference Article. Vol. I. Processing of Ceramics. - Elsevier, 1989. - 592-603.
The solid solution (Al2OC)1-x(AlN)x is more stable than pure Al2OC, whether stable or metastable equilibrium occurs. Part of the phase equilibrium diagram of the pseudobinary system Al2OC-AlN is suggested.
Lihrmann J.-M., Zambetakis T., Daire M. High-Temperature Behavior of the Aluminum Oxycarbide Al2OC in the System Al2O3 - Al4C3 and with Additions of Aluminum Nitride // J. Am. Ceram. Soc. - 1989. - 72(9). - 1704-1709.
A large number of high-temperature experiments involving binary mixtures of alumina and aluminum carbide (Al4C3) were performed to clarify the behavior of the aluminum oxycarbide Al2OC. It is first shown from heat treatments on the molar composition 55Al2O3·45Al4C3 that, in conditions of stable equilibrium, Al2OC decomposes to Al4O4C and Al4C3 at 1715°C according to the reaction
4Al2OC = Al4O4C + Al4C3.
However, Al2OC can be obtained at room temperature from compositions of lower carbide contents (<20 mol%) and by rapid cooling. In that case Al2OC is solidified in a metastable state, and, when subsequently annealed to temperatures above 1200°C, its lattice reorganizes and progressively transforms into the lattice of Al4O4C according to the reaction
Al2O3 + xAl2OC = (1-x)Al2O3 + xAl4O4C.
This transformation is described in terms of TTT curves and accompanied by a decrease in hardness and wear resistance. Additions of AlN to Al2O3 and Al4C3 have been found to create a solid solution Al2OC-AlN in an unexpected region of ternary system Al2O3-Al4C3-AlN. As a result the quasi-binary section Al2OC-AlN of the ternary diagram Al2O3-Al4C3-AlN was extensively investigated. We report the solubility limit of AlN in Al2OC, the improved high-temperature stability of the Al2OC-AlN solid solution compared with pure Al2OC, and eventually the existence of a possible intermediate ternary compound of formula Al10O3C3N4.
Lihrmann J.-M. High Temperature Stability of the Aluminum Monooxycarbide Al2OC in the systems Al2O3-Al4C3 and Al2O3-Al4C3-AlN / 88th American Ceramic Society Annual Meeting. - Chicago, 1986.
[no abstract]
Lihrmann J.-M. Nouvelles céramiques dans le système C-Al-O-N; examen de leur aptitude à l'abrasion / Thèse Doct. Ing. - ENSCS. - Université Louis Pasteur, 1982.
[no abstract]
Morozumi S., Endo M., Kikuchi M., Hamajima K. Bonding Mechanism Between Silicon Carbide and Thin Foils of Reactive Metals // J. Mater. Sci. - 1985. - 20(11). - 3976-3982.
Pressureless-sintered SiC pieces and SiC single crystals were joined with foils of reactive metals at 1500°, for Ti and Zr foils, or at 1000° for Al/Ti/Al foils. It is suggested that the fairly high bond strength of Ti foil-joined SiC specimens might be attributed to the formation of a Ti3SiC2 compd., since good lattice matching between SiC and Ti3SiC2 was obtained in the SiC single crystals. In the Al/Ti/Al foil-joined SiC, high bond strength was obtained, but it decreased steeply at 600° because of a retained Al phase. The bond strength in the Zr foil-joined SiC was low.
Naka M., Okamoto I., Nishino T., Urai S. Wetting of Silicon Carbide by Copper-Titanium Alloys // Trans. JWRI. - 1989. - 18(2). - 27-32.
The contact angle of molten Cu-Ti alloys contg. ~60 at % Ti on SiC was studied by the sessile-drop method at 1373 K in a vacuum. The contact angle reached the equil. value at 3.6 ks. The equil. contact angle decreased drastically with increasing Ti content. Cu-Ti alloys with >30 at.% Ti had an equil. contact angle of .ltoreq.7.degree.. The addn. of Ti to Cu depressed the reaction of Cu with SiC by forming TiC and Ti3SiC2 at the SiC/Cu-Ti interface. This accounts for the superior wetting of the Cu-Ti alloys on SiC. The Cu-Ti alloys are applicable as filler metal for joining SiC.
Nishino T., Urai S., Okamoto I., Naka M. Reaction Between Copper-Titanium Alloys and Silicon Carbide // Koon Gakkaishi - 1989. - 15(6). - 294-296.
The reaction products formed between pressureless sintered SiC and molten Cu-50 at.%Ti alloy at 1373 K for 3.6 ks were investigated by microstructure observation and electron probe microanal. Double reaction layers formed at the interface between SiC and Cu-Ti alloy were identified as TiCx ~15 mm thick and Ti3SiC2 ~10 mm thick. Granular reaction products in the Cu-rich matrix were TiSi2 and Ti3SiC2. Reaction layers at the interface are attributable to the decrease in contact angle of molten Cu-Ti alloy on SiC.
Oden L. L., McCune R. A. Phase Equilibria in the Al-Si-C System // Metall. Trans. A. - 1987. - 18A. - 2005-2014.
[no abstract]
Oscroft R. J., Korgul P., Thompson D. P. Crystal Structure and Microstructure of Some New Silicon Aluminum Carbonitrides // Br. Ceram. Proc. - 1989. - 42 (Complex Microstruct.). - 33-47.
The compounds phases occur along this join, namely Al4Si3C6 (12H) and Al4Si4C7 (21R) with unit cell dimensions a =3.22, c = 31.77 A and a = 3.21, c = 55.22 A, respectively. These complement the isostructural Al-C-N phases Al7C3N3 and Al8C3N4. A 2nd polytypoid form of the 8H phase occurs with a 12R structure Al4SiC4 (8H) and Al4Si2C5 (15R) which occur along the Al4C3-SiC join are most easily prepared by reacting mixtures of Al4C3 and SiC. Two additional polytypoid phases. This is a more cubic stacked form of the Al4SiC4 arrangement and is structurally analogous to -Al4C3 which is the alternative (6H) polymorph of Al4C3. 4H-SiC occurs as the major phase in compounds along the Al4C3-SiC join close to SiC. This phase is Al-containing with a range of Al content of 1.2-2.3 at.%.
Pampuch R., Lis J., Stobierski L., Tymkiewicz M. Solid Combustion Synthesis Ti3SiC2 // J. Eur. Ceram. Soc. - 1989. - 5(5). - 283-287.
Using powders of Ti and Si and carbon black as reactants, a material composed mainly of the ternary compds. Ti3SiC2 and of minor amts. of TiC was synthesized by the method of solid combustion. Following ignition at 1050°, complete conversion of the reactants to the products was obsd. in 2-5 s. The product obtained from the molar compn. 3Ti:Si:2C has properties similar to the chem.-vapor deposition-derived polycryst. Ti3SiC2, which is a soft ceramic material capable of being shaped by metalworking methods nd shows a high resistance to oxidn. and to aggressive environments.
Schoennahl J., Willer B., Daire M. Aluminum Silicon Mixed Carbide (Al4SiC4): Preparation and Structural Data // J. Solid State Chem. - 1984. - 52. - 163-173. - (French).
An addition of aluminum to SiC promotes its densification through the formation of ternary carbide Al4SiC4. A method of preparation of this compound is proposed, and its composition formula has been determined. Al4SiC4 has an hexagonal structure, with a = 3.28 A, and c = 21.72 A. Single crystals have been studied by X-ray diffraction, electronic microprobe, and optical microscopy. An epitaxial growth effect was observed between Al4SiC4 and the carbide Al4C3, and the possible existence of a family of Al4C3(SiC)n compounds is proposed.
Sugahara Y., Sugimoto K.-I., Kuroda K., Kato C. Preparation of Silicon Carbide and Aluminum Silicon Carbide from a Montmorillonite-Polyacrylonitrile Intercalation Compound by Carbothermal Reduction // J. Am. Ceram. Soc. - 1988. - 71(7). - 325-327.
Both silicon carbide and aluminum silicon carbide have simultaneously been obtained directly from naturally occurring aluminosilicate by carbothermal reduction for the first time. A precursor of a montmorillonite-polyacrylonitrile (PAN) intercalation compound was heated at 1700 °C in Ar. For comparison, montmorillonite-carbon mixtures were similarly heated. -SiC, -SiC, and Al4Si2C5 formed from the montmorillonite-PAN intercalation compound. Mainly -Al4SiC4 was obtained with ternary carbides from the montmorillonite-carbon mixtures in addition to a large amount of -SiC. Hence, aluminum silicon carbide formation was affected by the mixing condition of the starting materials.
Touanen M., Teyssandier F., Ducarroir M. Thermodynamic Calculation of the Two Phased Deposition Domains with Silicon Carbide in the Silicon-Titanium-Carbon-Chlorinehydrogen Chemical System // J. Phys., Colloq. (C5, Proc. Eur. Conf. Chem. Vap. Deposition, 7th, 1989). - 1989. - 105-113.
New ceramic materials with dispersed phases within a SiC matrix in the Ti-Si-C chem. system seem very attractive to improve toughness properties. Deposition domains of SiC-TiC and SiC-Ti3SiC2 are detd. by thermodn. calcn. in the Si-Ti-C-Cl-H chem. complex system and presented in the coordinate system of the variance parameters. The representation of these domains in the coordinate system of the initial gas mixt. is then easily deduced whatever the bearing mol. considered. For a given compn. of the gas mixt. at equil., the ratio between the deposited phases can present very large variations according to the initial gas mixt.
Viala J. C., Fortier P., Bouix J. Formation of Aluminum Silicon Carbide (Al4SiC4) // Ann. Chim. (Paris). - 1986. - 11(4). - 235-246. - (French).
The preparation of Al4SiC4 from the elements and from the binary carbides Al4C3 and SiC was experimental studied at 1200-1800 K. The results are discussed in terms of thermodinamic equilibrium, reaction mechanisms and formation kinetics.
Vodop'yanov A. G., Serebryakova A. V., Kozhevnikov G. N. Kinetics and Mechanism of Interaction of Alumina with Carbon // Izv. Akad. Nauk SSSR, Met. - 1982. - 1. - 43-47. (Russian).
[no abstract]
Yokokawa H., Dokiya M., Fujishige M., Kameyama T., Ujiie S., Fukuda K. X-Ray Powder Diffraction Data for Two Hexagonal Aluminum Monoxycarbide Phases // J. Am. Ceram. Soc. - 1982. - 65(3). - 40-41.
Aluminum monoxycarbide formed when Al2O3 is reduced by carbon in the presence of Si3N4 give two X-ray diffraction profiles. The high-temperature phase exhibits the normal 2H wurtzite-type pattern, whereas the low-temperature phase produces three major lines in addition to the 2H profile. Interplanar spacings and lattice dimensions are reported, both phases can be regarded as solid solutions with AlN and / or SiC. It is suggested that the <beta>-Al4SiC4 reported by Barczak may have been a mixture of these monoxycarbides.
Yokokawa H., Fujishige M., Dokiya M., Kameyama T., Ujiie S., Fukuda K. Reduction of Alumina: Effect of Silicon Compounds on Oxycarbide Behavior // Trans. Japan Inst. Metals. - 1982. - 23(3). - 134-145.
Reduction of alumina with carbon has been examined in the presence of silicon compounds in an argon atmosphere with powder x-ray diffractometry on various parts of sample pellets placed in a relatively large temperature gradient. It has been found that the reduced chemical form of alumina at 2070 K depends strongly upon the initial form of silicon compounds; SiC addition enhanced the formation of carbide Al4SiC4, while Si3N4 addition provided a significant amount of Al2OC of two different hexagonal phases. In the reduction of alumina together with silica at 2070 K, alumina was reduced to Al4O4C more rapidly and significantly than in the reduction of alumina alone; a remarkable amount of Al2OC was also formed prior to Al4O4C. The resulting aluminum oxycarbides volatilized gradually from the higher temperature zone. At 2170 K, we observed no Al4O4C but Al2OC in the simultaneous reduction.
Yokokawa H., Fujishige M., Ujiie S., Dokiya M. Phase Relations Associated with the Aluminum Blast Furnace: Aluminum Oxycarbide Melts and Al-C-X (X=Fe, Si) Liquid Alloys // Metall. Trans. B. - 1987. - 18B. - 433-444.
The thermodynamic properties and the phase relations were evaluated and estimated for the Al-O-C, Al-Si-C, and Al-Fe-C systems which are important to understand the chemical behavior in an aluminum blast furnace. The mixing properties of binary liquid alloys, including metal-carbon systems, were represented by the Redlich-Kister equation. The properties of liquid Al-C and Si-C alloys were estimated so as to be consistent with their phase diagrams. The coefficients of Al-Fe and Fe-C liquids were evaluated from reported values for activity and enthalpy. The extrapolation to the higher order systems was made by Maggianu's method. The aluminum oxycarbide melt was represented by a subregular solution model. In the Al-O-C system, liquid alloy / oxycarbide melt equilibria were calculated and compared with earlier experimental results and estimates. Attempts were made to clarify the volatilization of aluminum oxycarbide melts, and also the carbidation of liquid aluminum alloys. An empirical correlation between the first terms of the Redlich-Kister equation for the enthalpies and the excess entropies was discussed.
Yokokawa H., Fujishige M., Ujiie S., Kameyama T., Dokiya M., Fukuda K. Volatilization of Aluminum Oxycarbides and of Alumina with Carbon in Reduction of Alumina // Trans. Japan Inst. Metals. - 1984. - 25(3). - 187-196.
The volatilization in the Al-O-C(-Si-Fe) system have been investigated mainly by thermal gravimetry in vacuum for four cases; (1) aluminum oxycarbides, (2) mixtures of alumina and carbon with and without additives (iron oxide, silicon nitride and silicon carbide), (3) mixtures of alumina and aluminum carbide or silicon carbide and (4) mixtures of alumina, silica (mullite), iron oxide and carbon. Al2OC evaporated essentially congruently, whereas Al4O4C evaporated incongruently; was found to be enhanced remarkably when iron was added, unchanged by SiC addition and prevented slightly in the prensence of Si3N4. The mixture of alumina and carbide volatilized at lower temperatures than did those of alumina and carbon. These features are discussed in terms of the equilibrium pressure in the light of previous results of reaction experiments focussed upon the oxycarbide formation.
Zambetakis T., Lihrmann J.-M., Larrere Y., Daire M. Stability of Pure and Aluminum Nitride-alloyed Aluminum Oxycarbide (Al2OC) and Influence on Abrasive Properties of Aluminum Oxide (Al2O3) - Aluminum Carbide (Al4C3) - Aluminum Nitride (AlN) Materials / Sci. Sintering [Proc. Round Table Conf. Sintering],7th. - Plenum: New York, N. Y., 1989. - 613-620.
Zeng K., Jin Z. Mechanism of the Interfacial Reaction in Silicon Carbide (SiC) Fiber-Reinforced Titanium Matrix Composites // Fuhe Cailiao Xuebao. - 1989. - 6(4). - 92-95.
The interfacial reactions in SiC fiber / Ti composites were analyzed by using phase diagrams and diffusion theory. The surface structure of SiC fibers affects the diffusion channels for SiC / Ti interfacial reactions. Such reactions are suppressed by coating the SiC fibers with TiC or C to form a Ti3SiC2 layer.
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