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Volume 14, Issue 2
Displaying 1-5 of 5 articles from this issue
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[in Japanese]1967 Volume 14 Issue 2 Pages 47-59
Published: May 15, 1967
Released on J-STAGE: May 22, 2009
JOURNAL OPEN ACCESSDownload PDF (4502K) -
Toshitaka Fuziyama1967 Volume 14 Issue 2 Pages 60-70
Published: May 15, 1967
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThis report relates to magnetic properties of sintered Alnico type permanent magnet. The effects of history of iron powders, degree of oxidation of iron, nickel, cobalt, and copper powders, degree of evacuation and sintering time, and magnetic field cooling rate were investigated. Forming pressure, sintering temperature, degree of evacuation in sintering process, magnetic field cooling rate (900-700°C) of sintered permanent NKS-3 magnet are 6T/cm2, 1270-1300°C (NKS-1DA : 1350°C), 10 -1-10-3mmHg, 3-13 minute respectively.
Carbonyl, reduced (MH-300⋅P) and electrolytic iron powders are adequate for producing sintered NKS permanent magnet, and magnetic properties are improved by reducing iron, nickel, cobalt and copper powders, with hydrogen. At least lhr was necessary at 1300°C for obtaining well sintered product.
The best times of magnetic field cooling are 5-7 and 10 min. for titanium and silicon addition respectively. Addition of titanium reduces both remanence and maximum energy product value but increases coercive force.View full abstractDownload PDF (630K) -
Tatsuo Sato, Katsuto Nakatsuka, Koshi Toita, Junzo Shimoiizaka1967 Volume 14 Issue 2 Pages 71-76
Published: May 15, 1967
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSThe magnetite obtained by simultanious precipitaton from the mixed solution of ferrous and ferric ion (1:2) does not show the magnetic transformation at low temperature, and it can be easily oxidized in air.
It is supposed that the solid-solution of magnetite-γ-hematite is formed by oxidation of precipitates in air, and when this solid-solution was heated in neutral atmosphere, it changes to the magnetite having the magnetic transfomation at low temperature and α-hematite.
This segregation temperature is varied by the precipitating time and temperature. On the other hand, the precipitate changes to γ-hematite by low temperature heating in air. The transition point from this γ-hematite to α-hematite is also varied by precipitating time and temperature.View full abstractDownload PDF (359K) -
Hiroyasu Mitani, Keiichiro Shoji1967 Volume 14 Issue 2 Pages 77-85
Published: May 15, 1967
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSIron-nickel and iron-nickel-phosphorus powder mixtures were pressed and sintered. The diffusion of nickel in the sintered specimens and the sintering process of the pressed compacts were studied. The results obtained are as follows:
(1) The temperature of α→γ transformation for sintered iron-3% nickel specimen decreases with decreasing sintering time owing to the nickel rich areas in the specimen.
(2) It was found that the diffusion of nickel is accelerated in the sintered iron-3% nickel-0.5% phosphorus specimen. This may be attributed to the faster diffusion of nickel into the b.c.c. iron formed by preferential diffusion of phosphorus.
(3) In the sintered iron-3% nickel-0.5% phosphorus specimen prepared by the addition of nickel-phosphorus mother alloy powder, the diffusion of nickel is retarded by the interaction of nickel and phosphorus.
(4) When nickel and phosphorus increase in the compact, nickel phosphide is formed during sintering. Thus the sintering process is similar to that of iron plus nickel-phosphorus mother alloy powder compact.View full abstractDownload PDF (424K) -
Hisashi Suzuki, Takaharu Yamamoto, Kawakatsu Ichiro1967 Volume 14 Issue 2 Pages 86-91
Published: May 15, 1967
Released on J-STAGE: December 04, 2009
JOURNAL OPEN ACCESSEffects of carbon content on the properties of WC-10%Fe, WC-5%Fe-5%Co and WC2.5%Fe-7.5%Co alloys (sintered in vacuum at 1450°C for 1 hr) were studied. The results are summarized as follows;
(1) Sintering temperature of these alloys was higher than that of WC-Co alloys.
(2) In WC-Fe alloys and also in WC-Fe-Co alloys containing less than 50-60%Co as binder, tungsten dissolved scarcely into binder phase irrespective of the carbon content in the alloys. This is an essential difference between WC-Fe base alloys and WC-Co ones.
(3) Magnetic saturation of WC-Fe alloy was not constant in the phase region in which free carbon formed, due to the formation of the complex carbide phase. Similar result was observed also in WC-Fe-Co alloys containing less than 50-60%Co in binder. Magnetic saturation of WC-Fe alloy with extremely high carbon content was equal to the value estimated by assuming that the binder consists of pure iron. Magnetic saturation of each alloy with extremely low carbon content decreased due to the formation of M 6C type compound (η phase).
(4) WC-Fe and WC-Fe-Co alloys contained M23C 6 or (M23C 6+M3C) type compounds in the region corresponding to the two phase region in WC-Co alloys. It appears that the region in WC-Fe-Co alloys shifts to the lower carbon side compared with that of WC-Co alloy.
(5) Transverse-rupture strength of WC-Fe alloy showed a maximum value at the carbon content at which a large amount of free carbon was formed. The carbon content giving maximum strength decreased with increasing cobalt content.
(6) Strength of WC-Fe and WC-Fe-Co alloys was inferior to that of WC-Co base and WC-Ni alloys. This might be due to the formation of complex carbide even in the region correspon-ding to the two phase region of WC-Co base alloys and also due to the fact that the binder was b.c.c. alloy more brittle than f.c.c. In WC-Fe-Co alloys solution-hardning might be respon-sible also.View full abstractDownload PDF (3499K)
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