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Volume 19, Issue 7
Displaying 1-5 of 5 articles from this issue
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[in Japanese], [in Japanese]1973 Volume 19 Issue 7 Pages 271-280
Published: February 25, 1973
Released on J-STAGE: November 19, 2010
JOURNAL FREE ACCESSDownload PDF (634K) -
Takeshi Kameoka, Takashi Kimura1973 Volume 19 Issue 7 Pages 281-285
Published: February 25, 1973
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn order to clarify the complex dimensional change which occurred during sintering of Fe-Cu-C sintered alloys, swelling and shrinkage during sintering cycle have been investigated by means of a specially-made dilatometer.
In both Fe-Cu and Fe-C binary powder compacts, the swelling at high temperature increased in proportion to the amount of respective constituents. However in the case of Fe-Cu-C ternary powder compacts, the amount of swelling at high temperature did not agree with the sum of that of each binary system. With increasing the contents of both Cu and C, the swelling at high temperature became larger, but inversely the dimensional change at room temperature was less. This phenomenon is closely relatel with not only the decrease of copper growth by the addition of C, but also the change of gradient of dilatometric curve during cooling in the range of γ phase, affected by the addition of more Cu and C.View full abstractDownload PDF (369K) -
Tohru Kohno, Teruhisa Watanabe1973 Volume 19 Issue 7 Pages 286-290
Published: February 25, 1973
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSA general equation on the bending curvature of iron powder compacts during bronze-infiltrating process was constructed by assuming that the infiltrating process would go through following four steps:
1) Generating of liquid phase from the bronze infiltrant.
2) Infiltrating of the liquid phase into the iron skeleton.
3) Dimensional changes of the skeleton during infiltrating process.
4) Bending of the skeleton based on the difference between dimensional changes of the upper and the lower parts of itself during infiltrating process.
That is, 1/ρ=K⋅Pr1/2⋅R-1⋅H-1{t1/2-(t-ty=H)1/2}
where, l/ρ: curvature of bending (cm-1)
K: constant
Pr: porosity of the skeleton
R: radius of the capillary (cm)
H: height of the skeleton (cm)
t: time (sec)
ty: time taken for liquid to infiltrate to the point of y, in the height direction of the skeleton (sec)
From experimental results of infiltration under several constant infiltrating conditions, it was confirmed on the whole that the general equation could he adapted to the actual infiltrating process.View full abstractDownload PDF (303K) -
D. Delic, T. Janackovic, D. Uskokovic, M.M. Ristic1973 Volume 19 Issue 7 Pages 291-301
Published: February 25, 1973
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe authors have studied the sintering kinetics of a-Nb205 by means of a comparative analysis under isothermal and non-isothermal conditions. It was demonstrated that there exists non-linear dependence between the effective diffusion coefficients and the reciprocal temperature value.
The change in the relative linear shrinkage rate
∂(ΔL/Lo)T/∂√τ
follows the law of distribution, very close to the normal distribution, the maximum of which is the result of the change in the material structure state due to the change in the disperse system "activity". As the point defect concentration is the function of the oxygen partial pressure and temperature, characterized by both the ever-decreasing and increasing functions, it has been demonstrated that the abrupt increase of the relative linear shrinkage rate is the result of the existence of some other structure defects.
The qualitative analysis of the sintering process carried out from aspect of the subatom electronic configuration theory indicates that the high temperature of the sintering of a-Nb2O5 is the result of the greats tatistic weight of the atoms with stable configuration of niobium.View full abstractDownload PDF (493K) -
Hideji Igarashi, Yasuo Kuroyanagi, Kiyoshi Okazaki1973 Volume 19 Issue 7 Pages 302-307
Published: February 25, 1973
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSNiZn ferrite groups of a constant grain size with the relative density ranging from 50 to 98% and the groups of a constant density with the grain size from 0.6 to 80μ were fabricated by the hot-pressing and the ordinary firing method. For each group, initial permeability and BH characteristics were systematically measured as a function of density and grain size.
The results obtained are summerized as follows:
(1) The relation between the density and permeability follows the logarithmic mixing rule.
(2) The maximum initial permeability increases linearly with increase of the grain size.
(3) Coercive force is in the linear relation with the reciprocal of grain size, but is almost independent of density.
(4) Remanent magnetic flux density depends strongly on density, but is almost independent of grain size.View full abstractDownload PDF (3853K)
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