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02884 Glass transition behavior and viscous flow working of Pd40Cu30Ni10P20 amorphous alloy
72 Refractorieskerami
00102883 Elastic constants and their pressure dependence of Zr4,Ti,4Cu,2,5NiSBe22.5C1 bulk metallic glass Wang, W. H. E/ ol. Appl. Phgs. Lerr., 1999, 74, (13). 1803-1805. A pulse echo overlap method was used to measure the acoustic velocities and their pressure dependence of hulk Zr4iTii4CuIZ sNi9BeZz sCi metallic glass (MG) up to 0.5 GPa. The elastic constants and thermodynamic parameters as well as the pressure dependence of the MG have been detected. Comparisons were made between the obtained elastic constants to that of other types of glasses. In addition, more information related to the elastic properties, microstructure and glass forming ability of the MG was obtained. 00/02884 Glass transition behavior and viscous flow working of Pd40Cu30Ni10PZ0 amorphous alloy Nishiyama, N. and Inoue, A. Mnrer. Tram.. JIM, 1999, 40. (I). 64-71. An examination took place of the viscous flow of the super-cooled liquid for a hulk amorphous Pd&uaaNiiaPza alloy, as a function of temperature and applied stress. The flow rate increases linearly with increasing applied stress, hut the viscosity is independent of stress. Thus, the viscous flow of the super-cooled liquid occurs via the Newtonian flow mechanism. The viscosity at a temperature just below crystallization is as low as 8.3 x 10’ Pas and the low viscosity reflects the high resistance of super-cooled liquid to crystallization. The viscosity measured by thermo-mechanical analysis is independent of applied stress and heating rate and can he expressed as a function of temperature. The amorphous alloy heated at 0.33 K/s up to 600 K can retain the super-cooled liquid state with a low viscosity of ~10” Pas for 1 ks. Die forging into a three-stage die with pitch circle diameters of 4, 5 and 6 mm and module of 0.3 was made for 120 s at 610 K under a compressive stress of 10 kPa and a three-stage gear was formed. The shape and dimensions of the gear are in agreement with the inner size of the die within Al%. The utilization of viscous flow in the super-cooled liquid was useful for secondary working of the bulk. 00102885 Heat capacity at the glass transition in IV-VVI glasses Srinivasan, A. and Nandakumar, K. Phps. Chem. Glrrsses, 1999, 40, (I), 4043. Differential scanning calorimetry measurements were used to detect the excess heat capacity (AC,) at the glass transition of Ge-Sh-Se, Ge-As-Te and Si-As-Te glasses. The composition dependence of the AC, the three glass systems belonging to the IV-V-VI group show features at certain compositions. Information ahout existing models were used during the discussion of these results. 00/02886 Improvement of ceramic characteristics in firing of ceramic greens containing auxiliary raw materials such as coal ash Murata, Y. Ed al. Jpn. Kokai Tokkyo Koho JP I I 157,914 [99 157.9141 (Cl. CO41333/13), I5 Jun 1999, Appl. 19971345.907, I Dee 1997. 3. (In Japanese) In firing ceramic greens containing clay-based raw materials and auxiliary raw materials containing organic substances, waste plastics are included in the raw materials to burn the organic substances in addition to the waste plastics during the firing at low temperature. During the firing, the organic substances disappear along with the waste plastics. The auxiliary raw materials maybe in the form of coal ashes that contain unburnt carbon. It is possible to recycle the ashes, both coal and fly, by the method to form ceramics without blisters or discoloration. Kinetic studies of crystallization in Ca,_,Mg,-(PO,), 00102887 Mosner, P. ef rrl. J. Therm. Anal. C&rim., 1998, 54, (3). 937-945. Differential scanning calorimetry was used to study the crystallization kinetics of Cai xMg,(PO,)z glasses for powder and hulk samples of the compositions x=0, 0.5 and 1.0. Both the Freedman and the Kissinger method produce activation energy values that are smaller for the mixed glass Ca sMga s(POa)a than for the glasses with x=0 and 1.0. For majority of the samples, the two-parameter Sestak-Berggren equation gives a clearer description of the crystallization kinetics; only for powder Ca(PO& and bulk Mg(POa)z does the Johnson-Mehl-Avrami model agree with the experimental data. 00102888 Kinetics of grain growth in ZrOP-based ceramics densified by explosive pressing Panova, T. I. er al. Inorg. Marrr., 1999, 35, (2). 176-179. A description is given of an explosive-pressing procedure, which allows one to prepare green compacts of yttria-stabilized cubic zirconia with a nearly 100% relative density. The kinetics of grain growth and sintering in powder compacts prepared by explosive and isostatic pressing are studied in the temperature range lOOO-1500°C by DTA, thermogravimetry, X-ray diffraction and electron microscopy. 00/02889 Modulated-temperature differential scanning calorimetry and Raman spectroscopy studies of As,SW~_~ glasses Wagner, T. er ol. J. Muter. Sci.. 1998, 33, (23). 5581-5588. Modulated-temperature differential scanning calorimetry (MTDSC) has been used to study the thermal properties of chalcogenide As,Sim x glasses in the glass transition region. All samples in this work were given the same thermal history by heating to a temperature above the glass transition, equilibrating and then cooling at a rate of 5”imin to of 20”. The reversing
(properties, production,
applications)
and non-reversing heat flows through the glass transformation region during both heating and cooling schedules were measured and the values of the parameters T,, AH, C, and AC,, which characterize the thermal events in the glass transition region, were determined as a function of the glass composition. The structurally determined parameters T,, AH, C, and AC,, reveal major extremes when the composition of As,S,~_, glass becomes As4&a, the same as the composition of the corresponding stoichiometric compound. In addition, ‘small thresholds’ were observed in these properties at 28.5 at % As (AsZa 5S71 5) around the same composition as that reported in the As-Se glasses. No such thermal analysis had been done on the As,Sioo x glasses previously. It is shown that As,S~_~ glasses where x ~25 at % As are formed from two glass phases. From Raman spectroscopy it was possible to correlate the MTDSC results with the structure of the As-S glasses and it was possible to establish the probable composition of the high temperature glass phase from MTDSC measurements, 00102890 Ni tracer diffusion in bulk metallic glass Zr55AiloNilOCu25 Nakajima, H. e/ ~1. Marer. Sci. Forum, 1999, 304-306. 367-371, In this paper, self-diffusion coefficients of nickel in hulk metallic glass Zr~sAlloNiloCuz~ were measured by an ion-beam sputter sectioning technique at 538-720 K. The temperature dependence of the diffusivities in the super-cooled liquid phase is much different from that in the amorphous phase below the glass transition temperature. The diffusivity in the super-cooled liquid phase is much larger than that extrapolated from the amorphous phase. This enhancement can be attributed to an increase in the temperature-dependent configuration entropy in the super-cooled liquid phase. 00102891 Non-equilibrium thermodynamic analysis of the concentration distribution of rare earth oxide at alumina transparent ceramic crystal boundary Su, C. el (11.Guisucrn~~~Xuehrro. 1998, 26. (6), 802-807. (In Chinese) Preparation of alumina transparent ceramics doped with rare earth oxide took place using high-purity AlzOa ultra-fine powder. The chemical composition at the crystal boundary of the transparent ceramics were observed and the concentration distribution of rare earth oxide in stable state was measured by electron microprobe analysis. Solute partial separation hehaviour at the crystal boundary was analysed using nonequilibrium thermodynamic theory. Based on the study, the concentration distribution of the additive at the crystal boundary of alumina transparent ceramics is the non-equilibrium thermodynamic hehaviour. MgO, LazO, and YzO? are in accordance with the coupling model in the stable state and are mainly concentrated at the crystal boundary. 00102892 Oxidation mechanisms of Si-TLC-0 fiber-bonded ceramics Tohyama, N. rr ul. J. Crrum. Sot. Jpn.. 1999, 107. (Feh), 147-152. (In Japanies) An investigation has been made into the oxidation mechanisms of Si-Ti-C-O fibre-bonded ceramics at 773-1773 K in air using thermogravimetric analysis, electron microscopy and X-ray diffraction. The materials showed mass loss due to oxidation of the carbon interface and free carbon in the fihres at the beginning of the oxidation tests. Then, mass gain due to the formation of silica on the surface of the fibres was observed. When heat-treated below 1023 K, most of the free carbon was oxidized and flexural strength decreased to almost zero. The free carbon contained in the materials was about 7.7 mass% and oxidized along the fihre direction. On the other hand, upon heat treatment above 1073 K, the oxidation of carbon was strongly inhibited due to a cristohalite coating formed on the surface of the specimen which maintained its initial strength even after oxidation for 100 h. The materials showed an excellent oxidation resistance even if oxidized at 973 K, after the formation of the cristohalite coating. 00102893 Porous ceramics and their manufacture from clinker ash Saiki, M. cl crl. Jpn. Kokai Tokkyo Koho JP I I 139.886 [99 139,886] (Cl. 6 Nov 1997. 5. (In CO4838/00), 25 May 1999, Appl. 1997/304,731. Japanese) Porous grains of clinker ash (aggregate) partially bind to each other in the ceramics via porous crystallized glass with pore size lo-100 pm. There are communicating pores with pore size 100-5000 pm among the aggregate grains. The ceramics may contain fly ash. The manufacture consists of a mix of 45-80 wt% clinker ash aggregate with grain size 1.5-10.0 mm and 20-55 wt% porous crystallized glass components (soda-lime glass and hydraulic cement), adding lo-25 wt% water to the mixture. Then there is the granulating, curing, forming at pressure 5-30 kg/cm into a plate or a block, curing and finally firing at 1000-1200”. The ceramics have high binding strength of aggregate grains and display excellent water retention and permeability. 00102894 Preparation and characterization of ZrF4-BaF,-EuF3 planar glass films by electron cyclotron resonance plasmaenhanced chemical vapor deposition Kawamoto, Y. er al. J. Marer. Sci., 1998, 33, (23), 5607-5611. Development took place of an electron cyclotron resonance plasmaenhanced chemical vapour deposition apparatus, which is suitable for producing planar fluoride glass films. A ZrF,-BaFz-EuF, planar glass film was synthesized by using ti-diketonates of Zr, Ba and Eu as starting
Fuel and Energy Abstracts
September
2000
319
00102883 Elastic constants and their pressure dependence of Zr4,Ti,4Cu,2,5NiSBe22.5C1 bulk metallic glass Wang, W. H. E/ ol. Appl. Phgs. Lerr., 1999, 74, (13). 1803-1805. A pulse echo overlap method was used to measure the acoustic velocities and their pressure dependence of hulk Zr4iTii4CuIZ sNi9BeZz sCi metallic glass (MG) up to 0.5 GPa. The elastic constants and thermodynamic parameters as well as the pressure dependence of the MG have been detected. Comparisons were made between the obtained elastic constants to that of other types of glasses. In addition, more information related to the elastic properties, microstructure and glass forming ability of the MG was obtained. 00/02884 Glass transition behavior and viscous flow working of Pd40Cu30Ni10PZ0 amorphous alloy Nishiyama, N. and Inoue, A. Mnrer. Tram.. JIM, 1999, 40. (I). 64-71. An examination took place of the viscous flow of the super-cooled liquid for a hulk amorphous Pd&uaaNiiaPza alloy, as a function of temperature and applied stress. The flow rate increases linearly with increasing applied stress, hut the viscosity is independent of stress. Thus, the viscous flow of the super-cooled liquid occurs via the Newtonian flow mechanism. The viscosity at a temperature just below crystallization is as low as 8.3 x 10’ Pas and the low viscosity reflects the high resistance of super-cooled liquid to crystallization. The viscosity measured by thermo-mechanical analysis is independent of applied stress and heating rate and can he expressed as a function of temperature. The amorphous alloy heated at 0.33 K/s up to 600 K can retain the super-cooled liquid state with a low viscosity of ~10” Pas for 1 ks. Die forging into a three-stage die with pitch circle diameters of 4, 5 and 6 mm and module of 0.3 was made for 120 s at 610 K under a compressive stress of 10 kPa and a three-stage gear was formed. The shape and dimensions of the gear are in agreement with the inner size of the die within Al%. The utilization of viscous flow in the super-cooled liquid was useful for secondary working of the bulk. 00102885 Heat capacity at the glass transition in IV-VVI glasses Srinivasan, A. and Nandakumar, K. Phps. Chem. Glrrsses, 1999, 40, (I), 4043. Differential scanning calorimetry measurements were used to detect the excess heat capacity (AC,) at the glass transition of Ge-Sh-Se, Ge-As-Te and Si-As-Te glasses. The composition dependence of the AC, the three glass systems belonging to the IV-V-VI group show features at certain compositions. Information ahout existing models were used during the discussion of these results. 00/02886 Improvement of ceramic characteristics in firing of ceramic greens containing auxiliary raw materials such as coal ash Murata, Y. Ed al. Jpn. Kokai Tokkyo Koho JP I I 157,914 [99 157.9141 (Cl. CO41333/13), I5 Jun 1999, Appl. 19971345.907, I Dee 1997. 3. (In Japanese) In firing ceramic greens containing clay-based raw materials and auxiliary raw materials containing organic substances, waste plastics are included in the raw materials to burn the organic substances in addition to the waste plastics during the firing at low temperature. During the firing, the organic substances disappear along with the waste plastics. The auxiliary raw materials maybe in the form of coal ashes that contain unburnt carbon. It is possible to recycle the ashes, both coal and fly, by the method to form ceramics without blisters or discoloration. Kinetic studies of crystallization in Ca,_,Mg,-(PO,), 00102887 Mosner, P. ef rrl. J. Therm. Anal. C&rim., 1998, 54, (3). 937-945. Differential scanning calorimetry was used to study the crystallization kinetics of Cai xMg,(PO,)z glasses for powder and hulk samples of the compositions x=0, 0.5 and 1.0. Both the Freedman and the Kissinger method produce activation energy values that are smaller for the mixed glass Ca sMga s(POa)a than for the glasses with x=0 and 1.0. For majority of the samples, the two-parameter Sestak-Berggren equation gives a clearer description of the crystallization kinetics; only for powder Ca(PO& and bulk Mg(POa)z does the Johnson-Mehl-Avrami model agree with the experimental data. 00102888 Kinetics of grain growth in ZrOP-based ceramics densified by explosive pressing Panova, T. I. er al. Inorg. Marrr., 1999, 35, (2). 176-179. A description is given of an explosive-pressing procedure, which allows one to prepare green compacts of yttria-stabilized cubic zirconia with a nearly 100% relative density. The kinetics of grain growth and sintering in powder compacts prepared by explosive and isostatic pressing are studied in the temperature range lOOO-1500°C by DTA, thermogravimetry, X-ray diffraction and electron microscopy. 00/02889 Modulated-temperature differential scanning calorimetry and Raman spectroscopy studies of As,SW~_~ glasses Wagner, T. er ol. J. Muter. Sci.. 1998, 33, (23). 5581-5588. Modulated-temperature differential scanning calorimetry (MTDSC) has been used to study the thermal properties of chalcogenide As,Sim x glasses in the glass transition region. All samples in this work were given the same thermal history by heating to a temperature above the glass transition, equilibrating and then cooling at a rate of 5”imin to of 20”. The reversing
(properties, production,
applications)
and non-reversing heat flows through the glass transformation region during both heating and cooling schedules were measured and the values of the parameters T,, AH, C, and AC,, which characterize the thermal events in the glass transition region, were determined as a function of the glass composition. The structurally determined parameters T,, AH, C, and AC,, reveal major extremes when the composition of As,S,~_, glass becomes As4&a, the same as the composition of the corresponding stoichiometric compound. In addition, ‘small thresholds’ were observed in these properties at 28.5 at % As (AsZa 5S71 5) around the same composition as that reported in the As-Se glasses. No such thermal analysis had been done on the As,Sioo x glasses previously. It is shown that As,S~_~ glasses where x ~25 at % As are formed from two glass phases. From Raman spectroscopy it was possible to correlate the MTDSC results with the structure of the As-S glasses and it was possible to establish the probable composition of the high temperature glass phase from MTDSC measurements, 00102890 Ni tracer diffusion in bulk metallic glass Zr55AiloNilOCu25 Nakajima, H. e/ ~1. Marer. Sci. Forum, 1999, 304-306. 367-371, In this paper, self-diffusion coefficients of nickel in hulk metallic glass Zr~sAlloNiloCuz~ were measured by an ion-beam sputter sectioning technique at 538-720 K. The temperature dependence of the diffusivities in the super-cooled liquid phase is much different from that in the amorphous phase below the glass transition temperature. The diffusivity in the super-cooled liquid phase is much larger than that extrapolated from the amorphous phase. This enhancement can be attributed to an increase in the temperature-dependent configuration entropy in the super-cooled liquid phase. 00102891 Non-equilibrium thermodynamic analysis of the concentration distribution of rare earth oxide at alumina transparent ceramic crystal boundary Su, C. el (11.Guisucrn~~~Xuehrro. 1998, 26. (6), 802-807. (In Chinese) Preparation of alumina transparent ceramics doped with rare earth oxide took place using high-purity AlzOa ultra-fine powder. The chemical composition at the crystal boundary of the transparent ceramics were observed and the concentration distribution of rare earth oxide in stable state was measured by electron microprobe analysis. Solute partial separation hehaviour at the crystal boundary was analysed using nonequilibrium thermodynamic theory. Based on the study, the concentration distribution of the additive at the crystal boundary of alumina transparent ceramics is the non-equilibrium thermodynamic hehaviour. MgO, LazO, and YzO? are in accordance with the coupling model in the stable state and are mainly concentrated at the crystal boundary. 00102892 Oxidation mechanisms of Si-TLC-0 fiber-bonded ceramics Tohyama, N. rr ul. J. Crrum. Sot. Jpn.. 1999, 107. (Feh), 147-152. (In Japanies) An investigation has been made into the oxidation mechanisms of Si-Ti-C-O fibre-bonded ceramics at 773-1773 K in air using thermogravimetric analysis, electron microscopy and X-ray diffraction. The materials showed mass loss due to oxidation of the carbon interface and free carbon in the fihres at the beginning of the oxidation tests. Then, mass gain due to the formation of silica on the surface of the fibres was observed. When heat-treated below 1023 K, most of the free carbon was oxidized and flexural strength decreased to almost zero. The free carbon contained in the materials was about 7.7 mass% and oxidized along the fihre direction. On the other hand, upon heat treatment above 1073 K, the oxidation of carbon was strongly inhibited due to a cristohalite coating formed on the surface of the specimen which maintained its initial strength even after oxidation for 100 h. The materials showed an excellent oxidation resistance even if oxidized at 973 K, after the formation of the cristohalite coating. 00102893 Porous ceramics and their manufacture from clinker ash Saiki, M. cl crl. Jpn. Kokai Tokkyo Koho JP I I 139.886 [99 139,886] (Cl. 6 Nov 1997. 5. (In CO4838/00), 25 May 1999, Appl. 1997/304,731. Japanese) Porous grains of clinker ash (aggregate) partially bind to each other in the ceramics via porous crystallized glass with pore size lo-100 pm. There are communicating pores with pore size 100-5000 pm among the aggregate grains. The ceramics may contain fly ash. The manufacture consists of a mix of 45-80 wt% clinker ash aggregate with grain size 1.5-10.0 mm and 20-55 wt% porous crystallized glass components (soda-lime glass and hydraulic cement), adding lo-25 wt% water to the mixture. Then there is the granulating, curing, forming at pressure 5-30 kg/cm into a plate or a block, curing and finally firing at 1000-1200”. The ceramics have high binding strength of aggregate grains and display excellent water retention and permeability. 00102894 Preparation and characterization of ZrF4-BaF,-EuF3 planar glass films by electron cyclotron resonance plasmaenhanced chemical vapor deposition Kawamoto, Y. er al. J. Marer. Sci., 1998, 33, (23), 5607-5611. Development took place of an electron cyclotron resonance plasmaenhanced chemical vapour deposition apparatus, which is suitable for producing planar fluoride glass films. A ZrF,-BaFz-EuF, planar glass film was synthesized by using ti-diketonates of Zr, Ba and Eu as starting
Fuel and Energy Abstracts
September
2000
319