Pub Date : 2000-10-20DOI: 10.2320/MATERTRANS1989.41.1287
Tetsuya Suzuki, T. Fukuyama, M. Tada, Y. Tomota, T. Tsujimoto
A Ti-44.1 at%Al-1.6 at%Mn alloy with a unidirectionally oriented lamellar structure was made by using heavy extrusion of a mixture of titanium and Al-Mn alloy powder followed by reactive sintering under HIP. Compression tests were performed for 5 × 5 × 6 mm 3 specimens prepared in such a way that the angle between the extrusion direction and the compression axis became 0°, 30°, 45°, 60° or 90°. The yield strength at 293 K is found to strongly depend on the above angle, i.e., the 0° specimen shows the highest strength, the 90° specimen the second while the other specimens show much lower strengths. A similar anisotropic yield strength is observed for the results obtained at 1073 K although the strength of the 0° specimen is much higher than that in the 90° one. Anisotropic deformation behavior observed in the present investigation is discussed in comparison with that for TiAl polysynthetically twinned crystals.
{"title":"Anisotropy in Strength of a TiAl Base Polycrystal with Unidirectionally Oriented Lamellae","authors":"Tetsuya Suzuki, T. Fukuyama, M. Tada, Y. Tomota, T. Tsujimoto","doi":"10.2320/MATERTRANS1989.41.1287","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1287","url":null,"abstract":"A Ti-44.1 at%Al-1.6 at%Mn alloy with a unidirectionally oriented lamellar structure was made by using heavy extrusion of a mixture of titanium and Al-Mn alloy powder followed by reactive sintering under HIP. Compression tests were performed for 5 × 5 × 6 mm 3 specimens prepared in such a way that the angle between the extrusion direction and the compression axis became 0°, 30°, 45°, 60° or 90°. The yield strength at 293 K is found to strongly depend on the above angle, i.e., the 0° specimen shows the highest strength, the 90° specimen the second while the other specimens show much lower strengths. A similar anisotropic yield strength is observed for the results obtained at 1073 K although the strength of the 0° specimen is much higher than that in the 90° one. Anisotropic deformation behavior observed in the present investigation is discussed in comparison with that for TiAl polysynthetically twinned crystals.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"67 1","pages":"1287-1292"},"PeriodicalIF":0.0,"publicationDate":"2000-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79847033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1150
T. Okazaki, K. Sawaguchi, M. Homma
We have observed superparamagnetic behaviors and giant magnetoresistance in Ni 3 Mn alloy annealed at 673 and 693 K for several periods. The coercive force is small of 0.14 ∼ 0.44 kA.m -1 in these inhomogeneous alloys. The average size of the ferromagnetic cluster increases from ∼2.8 to ∼10nm with long-range ordering. The saturation magnetization also increases with a volume fraction, e, in the ordered regions and reaches to 0.92 T at e ∼ 80% where the alloy is ferromagnetic. These results suggest that the present Ni 3 Mn alloys are magnetically soft due to the nanocrystalline morphology: ordered ferromagnetic domains with nanometer in size are distributed in a disordered nonmagnetic matrix.
{"title":"Soft Magnetic Properties in Nano-scale Inhomogeneous Ni3Mn Alloys","authors":"T. Okazaki, K. Sawaguchi, M. Homma","doi":"10.2320/MATERTRANS1989.41.1150","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1150","url":null,"abstract":"We have observed superparamagnetic behaviors and giant magnetoresistance in Ni 3 Mn alloy annealed at 673 and 693 K for several periods. The coercive force is small of 0.14 ∼ 0.44 kA.m -1 in these inhomogeneous alloys. The average size of the ferromagnetic cluster increases from ∼2.8 to ∼10nm with long-range ordering. The saturation magnetization also increases with a volume fraction, e, in the ordered regions and reaches to 0.92 T at e ∼ 80% where the alloy is ferromagnetic. These results suggest that the present Ni 3 Mn alloys are magnetically soft due to the nanocrystalline morphology: ordered ferromagnetic domains with nanometer in size are distributed in a disordered nonmagnetic matrix.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"96 3 1","pages":"1150-1153"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77549394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1247
Y. Okazaki, E. Nishimura
Ti alloy disks were separately worn with pins of the same alloy or apatite ceramics in Eagle's medium. Wear powders sterilized in either a heating oven or ethanol were separately added to culture media. The effect of the Ti wear powder sterilized in a heating oven on cell viability was smaller than that of powder sterilized in ethanol. The effect of wear powder generated with the apatite ceramic pin on cell viability was also larger than that generated by the alloy pin. The relative growth ratios of L929 and MC3T3-El cells for Ti-6Al-4V alloy wear powder sterilized in ethanol decreased from a smaller amount than those of the Ti-15Zr-4Nb-4Ta and Ti-15Sn-4Nb-2Ta alloy wear powders. The concentration of V released from the wear powder into the medium increased moderately with increasing wear powder. This effect was approximately in agreement with the results estimated from medium extraction with high-purity V particles. For the Ti-15Zr-4Nb-4Ta and Ti-15Sn-4Nb-2Ta alloy wear powders sterilized in ethanol, the maximum Ti concentration released from the wear powder was approximately in agreement with the results obtained with high-purity Ti particles. On the contrary, for Zr, Nb, Ta and Sn, the maximum metal concentrations released from the wear powders were lower than those obtained with high-purity metal particles.
{"title":"Effect of Metal Released from Ti Alloy Wear Powder on Cell Viability","authors":"Y. Okazaki, E. Nishimura","doi":"10.2320/MATERTRANS1989.41.1247","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1247","url":null,"abstract":"Ti alloy disks were separately worn with pins of the same alloy or apatite ceramics in Eagle's medium. Wear powders sterilized in either a heating oven or ethanol were separately added to culture media. The effect of the Ti wear powder sterilized in a heating oven on cell viability was smaller than that of powder sterilized in ethanol. The effect of wear powder generated with the apatite ceramic pin on cell viability was also larger than that generated by the alloy pin. The relative growth ratios of L929 and MC3T3-El cells for Ti-6Al-4V alloy wear powder sterilized in ethanol decreased from a smaller amount than those of the Ti-15Zr-4Nb-4Ta and Ti-15Sn-4Nb-2Ta alloy wear powders. The concentration of V released from the wear powder into the medium increased moderately with increasing wear powder. This effect was approximately in agreement with the results estimated from medium extraction with high-purity V particles. For the Ti-15Zr-4Nb-4Ta and Ti-15Sn-4Nb-2Ta alloy wear powders sterilized in ethanol, the maximum Ti concentration released from the wear powder was approximately in agreement with the results obtained with high-purity Ti particles. On the contrary, for Zr, Nb, Ta and Sn, the maximum metal concentrations released from the wear powders were lower than those obtained with high-purity metal particles.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"1 1","pages":"1247-1255"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89562676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1111
M. Shimode, Y. Hayashi, M. Sasaki, K. Mukaida
New delafossite-type CuInO 2 was synthesized by ion exchange reaction of CuCl with α-NaFeO 2 -type NaInO 2 or with α-LiFeO 2 -type LiInO 2 . According to the XRD, after 144 h the main product obtained at 623 K was CuInO 2 in either starting material. Lattice parameters of CuInO 2 derived from NaInO 2 or LiInO 2 as determined by Rietveld analysis, are a = 329.01 pin, c = 1738.8 pm, and a = 329.22 pm, c = 1738.8 pm, respectively.
通过CuCl与α-NaFeO - 2型naino2或α- lifeo2型LiInO - 2离子交换反应，合成了新的延迟岩型CuInO - 2。XRD结果表明，在623 K下，144h后得到的主要产物均为CuInO 2。通过Rietveld分析，由naino2和LiInO 2得到的CuInO 2晶格参数分别为a = 329.01 pin, c = 1738.8 pm, a = 329.22 pm, c = 1738.8 pm。
{"title":"Ion Exchange Synthesis and Structure of New Delafossite-Type CuInO2","authors":"M. Shimode, Y. Hayashi, M. Sasaki, K. Mukaida","doi":"10.2320/MATERTRANS1989.41.1111","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1111","url":null,"abstract":"New delafossite-type CuInO 2 was synthesized by ion exchange reaction of CuCl with α-NaFeO 2 -type NaInO 2 or with α-LiFeO 2 -type LiInO 2 . According to the XRD, after 144 h the main product obtained at 623 K was CuInO 2 in either starting material. Lattice parameters of CuInO 2 derived from NaInO 2 or LiInO 2 as determined by Rietveld analysis, are a = 329.01 pin, c = 1738.8 pm, and a = 329.22 pm, c = 1738.8 pm, respectively.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"42 1","pages":"1111-1113"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86878549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1161
K. Uetani, H. Kajiyama, T. Yamaguchi, K. Nose, K. Onisawa, T. Minemura
We have prepared ultra thin TiN films using an advanced ion-plating (AIP) apparatus developed by ShinMaywa Industries. In AIP, RF and/or DC bias voltages are applied to the substrate holder and then a capacitor is formed between the substrate holder and the chamber. Eventually, it becomes easy to sustain a stable plasma at Ar pressures at as low as 10 -3 Pa. We clarified the characteristics of the AIP method through the deposition of ultra thin TiN films and examined new application areas for TiN thin films. TiN thin films (thickness: 5 and 25 nni) were prepared by AIP and also by DC sputtering without substrate heating. Then we measured the resistivity and observed the nanometer scale surface morphology of the thin films. Although the initial resistivities of both films were close (200 x 10 -8 Ω.m), the resistivity of the sputtered film ruse to twice that of the AIP film 50 hours later. Atomic force microscopy measurements showed flat, fine grains spread uniformly over the surface in the AIP film, while many isolated crystal islands were formed in the sputtered film. Our findings indicated that the AIP films have a potential use as wiring material. We thought that the AIP deposition enhances surface migration more than sputtering does as a result of efficient excitation of impinging TiN clusters in the Ar plasma region.
{"title":"Ultra Thin TiN Films Prepared by an Advanced Ion-Plating Method","authors":"K. Uetani, H. Kajiyama, T. Yamaguchi, K. Nose, K. Onisawa, T. Minemura","doi":"10.2320/MATERTRANS1989.41.1161","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1161","url":null,"abstract":"We have prepared ultra thin TiN films using an advanced ion-plating (AIP) apparatus developed by ShinMaywa Industries. In AIP, RF and/or DC bias voltages are applied to the substrate holder and then a capacitor is formed between the substrate holder and the chamber. Eventually, it becomes easy to sustain a stable plasma at Ar pressures at as low as 10 -3 Pa. We clarified the characteristics of the AIP method through the deposition of ultra thin TiN films and examined new application areas for TiN thin films. TiN thin films (thickness: 5 and 25 nni) were prepared by AIP and also by DC sputtering without substrate heating. Then we measured the resistivity and observed the nanometer scale surface morphology of the thin films. Although the initial resistivities of both films were close (200 x 10 -8 Ω.m), the resistivity of the sputtered film ruse to twice that of the AIP film 50 hours later. Atomic force microscopy measurements showed flat, fine grains spread uniformly over the surface in the AIP film, while many isolated crystal islands were formed in the sputtered film. Our findings indicated that the AIP films have a potential use as wiring material. We thought that the AIP deposition enhances surface migration more than sputtering does as a result of efficient excitation of impinging TiN clusters in the Ar plasma region.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"1 1","pages":"1161-1163"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90342545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1176
E. Wakai, A. Hishinuma, H. Abe, S. Takaki, K. Abiko
The effect of radiation on microstructural evolution and phase transformation in Fe-50Cr-5W and Fe-50Cr-8W model alloys was examined. The 300keV Fe + ion irradiation was performed at temperatures of 550, 600, 670, and 700°C at a rate of 1.4 × 10 18 ions/m 2 s for (1.2-1.8) x 10 3 s in a transmission electron microscope (TEM). The damage peak level corresponded to about 190-285 dpa. The peak depth positions of damage and Fe + ion were about 60 and 100 nm, respectively. Dislocation loops were observed in the Fe-50Cr-W alloys up to 700°C. A Laves phase of tens of nanometers in size was formed in the Fe-50Cr-W alloys within a few minutes, but the formation of Laves phase decreased with increasing irradiation temperature. Sigma-phase grains of about 50-100 nm in size and micro-crystallines were observed in the alloys irradiated at 670 and 700°C. However, in the specimen aged at 700°C for 1000 h and the one aged at 700°C for 10 h after 80% CW, only the Laves phase had formed and no sigma phase was observed in the Fe-50Cr-W alloys. These results indicate that Fe + ion irradiation can strongly influence the Laves and sigma phase transformations, and microstructural development, in the Fe-50Cr-W alloys.
{"title":"Microstructural Evolution of Fe-Cr-W Model Alloys During Fe^+ Ion Irradiation","authors":"E. Wakai, A. Hishinuma, H. Abe, S. Takaki, K. Abiko","doi":"10.2320/MATERTRANS1989.41.1176","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1176","url":null,"abstract":"The effect of radiation on microstructural evolution and phase transformation in Fe-50Cr-5W and Fe-50Cr-8W model alloys was examined. The 300keV Fe + ion irradiation was performed at temperatures of 550, 600, 670, and 700°C at a rate of 1.4 × 10 18 ions/m 2 s for (1.2-1.8) x 10 3 s in a transmission electron microscope (TEM). The damage peak level corresponded to about 190-285 dpa. The peak depth positions of damage and Fe + ion were about 60 and 100 nm, respectively. Dislocation loops were observed in the Fe-50Cr-W alloys up to 700°C. A Laves phase of tens of nanometers in size was formed in the Fe-50Cr-W alloys within a few minutes, but the formation of Laves phase decreased with increasing irradiation temperature. Sigma-phase grains of about 50-100 nm in size and micro-crystallines were observed in the alloys irradiated at 670 and 700°C. However, in the specimen aged at 700°C for 1000 h and the one aged at 700°C for 10 h after 80% CW, only the Laves phase had formed and no sigma phase was observed in the Fe-50Cr-W alloys. These results indicate that Fe + ion irradiation can strongly influence the Laves and sigma phase transformations, and microstructural development, in the Fe-50Cr-W alloys.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"3 1","pages":"1176-1179"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72824204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1184
H. Takabayashi, Y. Kato, T. Kagotani, D. Book, S. Sugimoto, M. Homma, H. Ota, Y. Houjou
This paper describes the effect of crystal orientation on the electromagnetic wave absorption properties of barium M-type (Ba-M) ferrite. in which Fe 3+ was substituted by (Ti 0.5 Mn 0.5 ) 3+ . The BaFe 9 (Ti 0.5 Mn 0.5 ) 3 O 19 sintered samples were prepared by a conventional powder metallurgy technique, in which and the c-axes of the powder particles were aligned in a magnetic field during compaction. After sintering. toroidally shaped samples were formed whose c-axes were aligned at certain angles (θ) to the sample thickness (d), and their microwave absorption properties were investigated in the GHz frequency range. It was found that the maximum values of the complex permeability (μ r = μ' r - jμ r ) increased with decreasing θ. The θ = 0° sample exhibited the highest μ r value, which resulted in the smallest matching thickness (d m ) of 0.57 mm with a reftection loss (R.L.) less than -20 dB at 12.05 GHz. In addition, increasing the sintering time had the effect of increasing μ n r ; reaching a μ n r value of 6.0 after sintering for 100h. As a result, the matching thickness decreased from 0.72 to 0.51 mm which is 30% smaller than for an isotropic sample sintered for 10h. Therefore, it is concluded that the degree of crystallographic alignment ol the sample and the sintering time used are both important factors in obtaining good electromagnetic wave absorption properties with a smaller matching thickness, in Ba M-type microwave absorbers.
{"title":"Effect of Crystal Orientation on the Magnetic Resonance Properties of M-Type Hexagonal Ferrites","authors":"H. Takabayashi, Y. Kato, T. Kagotani, D. Book, S. Sugimoto, M. Homma, H. Ota, Y. Houjou","doi":"10.2320/MATERTRANS1989.41.1184","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1184","url":null,"abstract":"This paper describes the effect of crystal orientation on the electromagnetic wave absorption properties of barium M-type (Ba-M) ferrite. in which Fe 3+ was substituted by (Ti 0.5 Mn 0.5 ) 3+ . The BaFe 9 (Ti 0.5 Mn 0.5 ) 3 O 19 sintered samples were prepared by a conventional powder metallurgy technique, in which and the c-axes of the powder particles were aligned in a magnetic field during compaction. After sintering. toroidally shaped samples were formed whose c-axes were aligned at certain angles (θ) to the sample thickness (d), and their microwave absorption properties were investigated in the GHz frequency range. It was found that the maximum values of the complex permeability (μ r = μ' r - jμ r ) increased with decreasing θ. The θ = 0° sample exhibited the highest μ r value, which resulted in the smallest matching thickness (d m ) of 0.57 mm with a reftection loss (R.L.) less than -20 dB at 12.05 GHz. In addition, increasing the sintering time had the effect of increasing μ n r ; reaching a μ n r value of 6.0 after sintering for 100h. As a result, the matching thickness decreased from 0.72 to 0.51 mm which is 30% smaller than for an isotropic sample sintered for 10h. Therefore, it is concluded that the degree of crystallographic alignment ol the sample and the sintering time used are both important factors in obtaining good electromagnetic wave absorption properties with a smaller matching thickness, in Ba M-type microwave absorbers.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"55 1","pages":"1184-1187"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85640465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1208
T. Kamimura, S. Nasu
The rust formed on weathering steel exposed to an industrial environment for 15 years was characterized by means of X-ray powder diffraction, Raman spectroscopy, electron probe microanalysis and Mossbauer spectroscopy. The rust consists of the crystalline α-FeOOH, γ-FeOOH and an X-ray amorphous phase, The amount of the X-ray amorphous phase exceeds 50% of the total amount of the rust. The 57 Fe Mossbauer spectra observed at 10 K indicate that the rust contains only α-FeOOH and γ-FeOOH. The X-ray amorphous phase in the rust layer. which gives no peak in the X-ray diffraction pattern, is mainly α-FeOOH which shows a paramagnetic doublet due to the superparamagnetism occurring for small particle sizes at room temperature, The particle size of α-FeOOH is widely distributed and the inner rust layer contains relatively well-crystallized α-FeOOH compared to the outer layer.
{"title":"Mössbauer spectroscopic study of rust formed on a weathering steel exposed for 15 years in an industrial environment","authors":"T. Kamimura, S. Nasu","doi":"10.2320/MATERTRANS1989.41.1208","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1208","url":null,"abstract":"The rust formed on weathering steel exposed to an industrial environment for 15 years was characterized by means of X-ray powder diffraction, Raman spectroscopy, electron probe microanalysis and Mossbauer spectroscopy. The rust consists of the crystalline α-FeOOH, γ-FeOOH and an X-ray amorphous phase, The amount of the X-ray amorphous phase exceeds 50% of the total amount of the rust. The 57 Fe Mossbauer spectra observed at 10 K indicate that the rust contains only α-FeOOH and γ-FeOOH. The X-ray amorphous phase in the rust layer. which gives no peak in the X-ray diffraction pattern, is mainly α-FeOOH which shows a paramagnetic doublet due to the superparamagnetism occurring for small particle sizes at room temperature, The particle size of α-FeOOH is widely distributed and the inner rust layer contains relatively well-crystallized α-FeOOH compared to the outer layer.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"13 1","pages":"1208-1215"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85105482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1196
M. Orihashi, Y. Noda, Lidong Chen, T. Hirai
P-type Pb 1-x Sn x Te single crystals were prepared by the Bridgman method with different Sn content (x). Electrical conductivity (σ ), Hall coefficient (R H ) and thermal conductivity (κ) were measured in the temperature range from 300 to 700 K. The hole concentration (p) at 77 K changed in the range from 2.2 × 10 24 to 4.9 × 10 26 m -3 for a whole composition range, 0.0 ≤ x ≤ 1.0. The σ increased monotonously with increasing x, while the κ value exhibited a minimum at x = 0.25. The lattice thermal conductivity (κ lattice ) also changed with x showing a minimum at x = 0.25 ∼ 0.50. The carrier thermal conductivity (κ carrier ) was found to increase monotonously with increasing x. The ratio (σ/κ) of electrical conductivity to thermal conductivity was found to have a maximum at x = 0.50. These results indicate that the electrical and thermal properties are sensitively influenced by phonon scattering by the disordered atomic arrangements in the solid solution. The possible enhancement of thermoelectric performance was suggested by forming the Pb 1-x Sn x Te solid solutions.
采用Bridgman法制备了不同Sn含量(x)的p型pb1 -x Sn x Te单晶，在300 ~ 700 K温度范围内测量了其电导率(σ)、霍尔系数(R H)和导热系数(κ)。77 K时的空穴浓度(p)在整个组成范围内变化范围为2.2 × 1024 ~ 4.9 × 26 m -3, 0.0≤x≤1.0。σ值随x的增加而单调增加，κ值在x = 0.25时达到最小值。晶格导热系数(κ晶格)也随x的变化而变化，在x = 0.25 ~ 0.50处达到最小值。载流子导热系数(κ载流子)随x的增加而单调增加，电导率与导热系数之比(σ/κ)在x = 0.50时达到最大值。这些结果表明，固溶体中无序原子排列对声子散射有敏感的影响。提出了通过形成pb1 -x Sn x Te固溶体来提高热电性能的可能性。
{"title":"Effect of Sn Content on the Electrical Properties and Thermal Conductivity of Pb1−xSnxTe","authors":"M. Orihashi, Y. Noda, Lidong Chen, T. Hirai","doi":"10.2320/MATERTRANS1989.41.1196","DOIUrl":"https://doi.org/10.2320/MATERTRANS1989.41.1196","url":null,"abstract":"P-type Pb 1-x Sn x Te single crystals were prepared by the Bridgman method with different Sn content (x). Electrical conductivity (σ ), Hall coefficient (R H ) and thermal conductivity (κ) were measured in the temperature range from 300 to 700 K. The hole concentration (p) at 77 K changed in the range from 2.2 × 10 24 to 4.9 × 10 26 m -3 for a whole composition range, 0.0 ≤ x ≤ 1.0. The σ increased monotonously with increasing x, while the κ value exhibited a minimum at x = 0.25. The lattice thermal conductivity (κ lattice ) also changed with x showing a minimum at x = 0.25 ∼ 0.50. The carrier thermal conductivity (κ carrier ) was found to increase monotonously with increasing x. The ratio (σ/κ) of electrical conductivity to thermal conductivity was found to have a maximum at x = 0.50. These results indicate that the electrical and thermal properties are sensitively influenced by phonon scattering by the disordered atomic arrangements in the solid solution. The possible enhancement of thermoelectric performance was suggested by forming the Pb 1-x Sn x Te solid solutions.","PeriodicalId":18264,"journal":{"name":"Materials Transactions Jim","volume":"47 4-5 1","pages":"1196-1201"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77501901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-09-20DOI: 10.2320/MATERTRANS1989.41.1118
Yao-Can Zhu, Y. Zhang, X. Li, K. Fujita, N. Iwamoto
A SiO 2 coating of about 2 μm was deposited onto γ-TiAl alloys by using a magnetron-sputtering coating method. The cyclic oxidation behavior of γ-TiAl alloys was investigated at 1123 K in air. The uncoated γ-TiAl specimen showed a high oxidation rate during the initially transient period of up to 220 ks, after which, a rapid mass loss was observed due to the partial scale spallation. In contrast, the SiO 2 -coated TiAl specimen exhibited an extremely low oxidation rate. It was found that the SiO 2 coating acted as an external barrier coating, thereby being capable of significantly suppressing the oxidation of γ-TiAl alloys.
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