巻号一覧
53 巻, 5 号
May
選択された号の論文の11件中1～11を表示しています
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研究
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門側 幸宏, 室田 慶人2006 年 53 巻 5 号 p. 391-396
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスThe gel of 3La2O3·2WO3 composition was prepared by the TW method from the starting mixture containing La(NO3)3 aqueous solution and WO3 powder with each small amount of tetraethyl orthosilicate (TEOS) and 2M-HCl as a catalyst, which was heated at a fixed temperature in the range of 800°C to 1200°C for 30 min. In the obtained material (the sample No.1), the formation of 3La2O3·2WO3 began at about 800°C and was most remarkable at 1000°C. However, in the case of the sample No.1, the diffraction lines for 7La2O3·8WO3, α-La2W2O9, La2O3, β-La2W2O9 and γ-La2WO6 were observed in addition to those for 3La2O3·2WO3. Therefore, pure 3La2O3·2WO3 in a single phase was not obtained at any heating temperature. Whereas in the case of the sample No.4, which was obtained by heating the gel with 8.99×10-3 mol KCl at 1000°C for 30 min, almost pure 3La2O3·2WO3 was obtained in a single phase, though slight γ-La2WO6 and β-La2W2O9 were present. It was thought that 3La2O3·2WO3 was obtained as a degradation product of 7La2O3·8WO3, simultaneously as a product of the reaction of La2O3 and γ-La2WO6 in the progress of its decomposition when a part of β-La2W2O9 decomposed to γ-La2WO6. Furthermore, it was thought that α-La2W2O9 was transformed into β-La2W2O9, because the minimum in intensity of α-La2W2O9 was corresponding well to the maximum in that of β-La2W2O9.抄録全体を表示PDF形式でダウンロード (579K) -
中村 満, 山田 智之, 市川 淳一2006 年 53 巻 5 号 p. 397-401
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスOn the influence of the amount of Zn-St type lubricant on rapid sintering of sintered steel, we prepared 4 types of specimens with different amount of lubricant. In this experiment, isothermal treatments (I.T) were done at 1223K and 1373K in 90s holding conditions. The purposes of isothermal treatment were delubricanting, degasification, diffusion of graphite and copper, and austenitizing of ferrite. The specimens were finally sintered at 1473K in 60s holding condition. As a result, Cu came to be in liquid phase when IT temperature was over the melting point of copper. This treatment was able to diffuse fully in intergranular and transgranular sites. That is to say, all specimens included lubricant were obtained with high radial crushing strengths (RCS). From isothermal treatment (1373K-90s holding condition) obtaining a good result, we tried to shorten the holding time in IT from 90s to 60s for the standpoint of omitted energy. All the specimens including lubricant were obtained with high RCS values, too. In brief, increase of the amount of lubricant were not influenced for sintering density as well as dimensional change less than 0.2%.抄録全体を表示PDF形式でダウンロード (1329K) -
橋本 等, 孫 正明, 多田 周二, 井上 陽介, 水野 光国2006 年 53 巻 5 号 p. 402-405
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスBonding of titanium silicon carbide Ti3SiC2 by using slurry spin coating and reactive sintering techniques was investigated. Ti, Si and TiC powders were blended at a molar ratio of Ti:Si:TiC=2:2:3, from which highly pure Ti3SiC2 can be synthesized, and suspended in ethanol to prepare slurry. Test pieces of Ti3SiC2 were spin coated with the slurry at various conditions and the composition of coated layer was analyzed by EDX. The coated layer had Si-rich and Ti-poor composition compared with the slurry. The test pieces coated with the slurry were superimposed one on the other and sintered by a hot press at various temperatures. During sintering, the powder blend in the coated layer was reacted and sintered, and the pieces were bonded. The bonding layer was 20 or 30 micrometers in thickness and showed finer grain size than the test pieces. The layer had pores in spots and the number of pores tended to decrease with increasing bonding temperature. The composition of bonding layer tended to move toward the composition of test pieces with increasing bonding temperature, which suggests the diffusion of Si and C between the bonding layer and test pieces.抄録全体を表示PDF形式でダウンロード (1312K)
特集：硬質材料のプロセス·構造制御の新たな展開
総報
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松原 秀彰2006 年 53 巻 5 号 p. 408
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスPDF形式でダウンロード (91K)
総説
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棚瀬 照義2006 年 53 巻 5 号 p. 409-418
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスSubmicro-grained WC-Co cemented carbide is very important tool material for solid endmills, PCB drills, etc. On manufacturing the alloy, addition of grain growth inhibitors is inevitable and many relating reports have been published. However, there are some problems left behind such as the sintering process, the mechanism of grain growth inhibition, etc. In this report, a summarization of author's investigations relating to those problems is introduced.
Submicro-grained WC-12mass%Co alloys with mono-doped 0.5mass%VC or 0.9mass%Cr3C2 were used as specimens which were heated up in vacuum to certain temperatures and immediately cooled. Some of them were fully sintered at 1380°C for 1hr. They were examined by density measurement, TG-DTA, SEM, HRTEM, etc.
Major results are as follows. (1) DTA revealed that addition of VC or Cr3C2 decreased a liquidus temperature by about 30 to 40°C. However, their addition retarded shrinkage from 1080°C for VC and 900°C for Cr3C2, and also retarded diffusion of Co onto WC grains and facetting of the grains up to about 1200°C, accompanied by delay in densification. Both alloys reached almost full density at 1320°C as well as non-doped alloy. (2) VC remarkably retarded grain growth from 1200°C, and Cr3C2 retarded it at 1380°C but not so remarkably as VC. (3) In VC-doped alloy, HRTEM revealed steps on WC grains consisted of WC(1010) and WC(0001), and segregation of V mainly on WC(0001)/Co interface. V was also detected at WC/WC grain boundary accompanied with Co, but not in the binder phase. Another V was observed substituting Co binder phase which was assumed to be (V, W)C. (4) In Cr3C2-doped alloy, such steps on WC grains were rarely observed. Segregation of Cr on WC grains was not always detected, but it was detected at WC/WC grain boundary with Co as well as in binder phase.
Some discussion on the mechanism of grain growth inhibition was presented basing on the results obtained. However, further and precise investigations are needed in order to comprehensively understand it.抄録全体を表示PDF形式でダウンロード (3650K)
受賞記念講演
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香山 滉一郎, 森下 政夫, 張 国鋒2006 年 53 巻 5 号 p. 419-429
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスThe phase diagrams of the Ni-Mo-B and Ni-W-B ternary systems in the region of less than 50mol%B were constructed by thermodynamic calculation, based on the data obtained by thermodynamic measurement of the related materials. We found three ternary eutectic points and three or two ternary peritecto-eutectic points as follows:
E1:L (1365K, 71.5mol%Ni-6.0mol%Mo-22.5mol%B)=(Ni)+Ni3B+NiMo2B2
E2:L (1355K, 62.5mol%Ni-2.5mol%Mo-30.5mol%B)=Ni3B+Ni2B+NiMo2B2
E3:L (1445K, 42.0mol%Ni-30.6mol%Mo-10.3mol%B)=(Ni)+NiMo+NiMo2B2
P1:L (1812K, 34.9mol%Ni-42.3mol%Mo-22.8mol%B)+MoB=Mo2B+NiMo2B2
P2:L (1633K, 42.3mol%Ni-40.4mol%Mo-17.3mol%B)+Mo=Mo2B+NiMo2B2
P3:L (1812K, 53.5mol%Ni-33.7mol%Mo-12.8mol%B)+Mo=NiMo+NiMo2B2
E1:L (1622K, 51.0mol%Ni-31.6mol%W-17.4mol%B)=(Ni)+W+NiW2B2
E2:L (1260K, 71.0mol%Ni-7.0mol%W-22.0mol%B)=(Ni)+Ni3B+NiW2B2
E3:L (1291K, 65.4mol%Ni-4.8mol%W-29.8mol%B)=Ni2B+Ni3B+NiW2B2
P1:L (2115K, 23.8mol%Ni-43.1mol%W-33.1mol%B)+WB=W2B+NiW2B2
P2:L (1657K, 48.9mol%Ni-33.1mol%W-18.0mol%B)+W2B=W+NiW2B2
The calculated phase diagrams are expected to be useful for the development of new Ni-based heat-, corrosion- or wear-resistance alloys.抄録全体を表示PDF形式でダウンロード (1045K)
研究
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久保 裕, 幸村 淳, 井寄 裕介, 川田 常宏2006 年 53 巻 5 号 p. 430-434
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスWC-0.40mass%VN-0.44mass%Cr3C2-8.0mass%Co alloy with different amount of carbon content using commercially available 0.4 micron WC powders were prepared by sintering and HIPing. In these alloys trace amount of V-rich phase were observed by EPMA analysis.
Quantification of V-rich phases was performed as follows. (1) The location of V-rich phase was determined by EPMA. (2) Determination of the same V-rich phase was performed by FE-SEM. (3) Cutting off the portion containing the V-rich phase and making thin film was done by FIB. (4) Determination of the size of V-rich phase was carried out by FE-TEM observation. (5) The threshold value was set by coincidation of the size by FE-TEM with peak width of EPMA line analysis. (6) EPMA V mapping image was binarized by the threshold value. (7) Area % was obtained by image analysis of binarized image. (8) Random 20 fields were analyzed by the same method mentioned above and average value was obtained.
The amount of V-rich phase in middle carbon alloy was 0.008 area% and the amount of V-rich phase increased with increasing carbon content from 0.001 to 0.051 area%.抄録全体を表示PDF形式でダウンロード (1500K) -
松野 恭司, 川上 優, 寺田 修, 林 宏爾2006 年 53 巻 5 号 p. 435-440
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスThe microstructures and properties of VC+Cr3C2 doped WC-2, 4mass%Co submicro-grained hardmetals that were prepared from WC powder of 0.12μm by hybrid sintering (a combination method of directly electrifying hot-press sintering with normal sintering, i.e., external heating pressureless sintering) and normal sintering were investigated, following the previous study on 10 mass% Co hardmetal.
The lowest densification sintering temperature for almost full density (≥99% of theoretical density) in hybrid sintering, e.g., for 2 mass% Co alloy, was lower by 40 K than in normal sintering, which was larger than that (30 K) for 10 mass% Co hardmetal. The minimum WC mean grain size and the maximum hardness HV of hybrid-sintered hardmetal were 0.19μm and 2650, respectively. These values were smaller and larger than those (0.22μm and 2460) of normal-sintered hardmetal, differing from 10 mass% Co hardmetal. The fracture toughness (Kc) at a definite hardness of hybrid hardmetal was superior with that of normal-sintered hardmetal in the same way as 10 mass% Co hardmetal. Thus, it was concluded that hybrid sintering has merits in the densification sintering temperature, grain size, hardness and fracture toughness, compared with normal sintering, particularly for low Co hardmetals.抄録全体を表示PDF形式でダウンロード (1232K)
研究速報
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坂本 竜一, 松尾 明, 今里 州一, 村上 清人, 松田 健次, 兼田 もと宏2006 年 53 巻 5 号 p. 441-446
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスCemented carbide is known as an excellent tribo-material and therefore applied to mechanical seals, bearings, dies, and so on. Recently, the research on tribo-properties has become more important for the tribo-material development in accordance with needs of improved wear resistance and higher operation speed. In this study, effect of WC-3mass%TiC-2mass%TaC binder-less cemented carbide with dispersed modular carbon on tribo-properties was evaluated and considered. In the result, the effectiveness of frictional surface feature and self lubrication due to dispersed carbon on tribo-properties were found.抄録全体を表示PDF形式でダウンロード (1309K)
Paper
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平田 浩郎, 岩永 健吾, 山崎 裕司, 高木 研一2006 年 53 巻 5 号 p. 447-451
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスRecently, super engineering plastics containing various kinds of fillers and a very corrosive fluorocarbon resin are increasing in the plastic injection molding. Injection molding machine parts used in severe molding conditions requires excellent mechanical properties and corrosion resistance of the part materials. In this paper, in order to investigate the applicability of Mo2NiB2 base cermets, having high corrosion resistance, into injection molding machine parts, the mechanical properties and corrosion resistance of the cermets with the composition of Ni-5.0mass%B-51.0mass%Mo-(17.5-X)mass%Cr-Xmass%V (X=0∼10.0) cermets were studied. Transverse rupture strength (TRS) and hardness of the cermets increased monotonically with increasing V content and reached the maximum values of 2.94GPa and 87.2HRA at 10.0mass%V (X=10.0), respectively. The excellent corrosion resistance for a molten fluorocarbon resin together with relatively high TRS was obtained up to 5.0mass%V (X=5.0).抄録全体を表示PDF形式でダウンロード (879K) -
角谷 均, 入舩 徹男2006 年 53 巻 5 号 p. 452-458
発行日: 2006年
公開日: 2006/12/19
ジャーナル オープンアクセスHigh-purity and super-hard nano-polycrystalline diamond has been successfully synthesized by direct conversion from high-purity graphite under static pressures above 15 GPa and temperatures above 2573 K. TEM analysis revealed that the polycrystalline diamond has a mixed texture of a homogeneous fine structure (particle size: 10-30 nm, formed in a diffusion process) and a lamellar structure (formed in a martensitic process). Differences in the direction of maximum compression force on graphite particles create different conversion processes to cubic diamond, leading to the mixed texture. Results of indentation hardness tests using super-hard synthetic diamond Knoop indenter showed the polycrystalline diamond has very high Knoop hardness of 120-145 GPa. On the contrary, the polycrystalline diamonds synthesized from the non-graphitic carbons at 15-18 GPa and 1873-2273 K have a single texture consisting of a very fine homogeneous structure (5-10 nm, formed in a diffusion process) without a lamellar structure and containing no hexagonal diamond phase. The hardness values of such single-nano polycrystalline diamonds from non-graphitic carbons (70-90 GPa) are significantly lower than that of polycrystalline diamond from graphite. The excessively small size of diamond particles and the absence of the lamella structure seem to lower the hardness of the polycrystalline diamond.抄録全体を表示PDF形式でダウンロード (1577K)
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