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Volume 32, Issue 10
Displaying 1-22 of 22 articles from this issue
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Hideo Abe, Kunio Ito1968 Volume 32 Issue 10 Pages 927-933
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIt has been reported by several investigators that well-defined columnar crystals of ferrite are developed in the decarburized zone of carbon steel, while no investigation has been carried out on the texture of the columnar crystal zone.
The authors found simple fibre textures in the columnar crystal zones developed in several carbon steels (C=0.3∼0.8%) by decarburizing in a wet H2+N2 atmosphere. The fibre axes of the texture which aligned parallel to the axes of the columnar crystals were near [012], deviated by ±5°∼10° along the [02\={1}] zone circle. The development of this type of fibre texture was observed when the steels were decarburized at temperatures between (Ac3+40°C) and 860°C. In the case of 0.2%C steel, in which (Ac3+40°C) was higher than 860°C, the above type of texture was not developed and a different fibre texture aligned in the [001] direction was observed.
Austenitization prior to the decarburizing anneal was necessary to obtain the sharp near [012] type texture. The sharpness of the texture was also affected by the degree of surface finish of the specimen as well as the H2O content of the decarburizing gas.
From observations on the developing process of the texture, it was concluded that the fibre texture was developed by the γ→α transformation at the surface of the steel and that the growth process of the columnar crystals beyond 30 μ had no effect on the development of the preferred orientation.View full abstractDownload PDF (2307K) -
Harue Wada, Kôki Gunji, Tsuguyasu Wada1968 Volume 32 Issue 10 Pages 933-938
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe solubility of nitrogen in liquid Ni, Cr and Fe-Ni, Fe-Cr systems has been measured in the temperature range from 1780° to 2200°C over wide composition ranges. The measurements were made by a levitation-melting method.
The solubility of nitrogen in Ni was very low and increased with increasing temperature. For the Fe-Ni system, it was decreased with increasing Ni content and increased with increasing temperature. The solubility of nitrogen in the Fe-Cr system was increased with increasing Cr content up to 4.1 wt% at 1900°C for pure Cr, and decreased with increasing temperature.
Values of the partial molar heat of solution Δ\barHN of nitrogen were determined. The Δ\barHN in the Fe-Ni system showed an approximately linear relation with the Ni concentration, while the relationship was not linear in the Fe-Cr system. Using a statistical-thermodynamical method, an equation was derived for expressing interaction parameter εN(X) in terms of the excess enthalpy and entropy, which could be determined from the solubility of each component. The equation provided a reasonable explanation for the linearity of Δ\barHN in the iron-poor absorber system.View full abstractDownload PDF (1872K) -
Genjiro Mima, Shinichi Morita, Junzo Takahashi, Masaharu Yamaguchi1968 Volume 32 Issue 10 Pages 939-943
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe mechanism in the gaseous reduction of iron ore is very confusing and presents many problems still unsolved.
This is because several processes are occurring simultaneously and moreover, there are a large number of variables. In order to provide additional information to the reduction mechanism, in this investigation, the structural change of the ore, especially, the formation process of the sponge iron has been studied by means of optical microscopy and electron microscopy. Itabira iron ore was inserted in a horizontal tube furnace and reduced at 900°C by a H2-H2O gas mixture. Thin foils of iron ore and reduced iron were prepared and examined by transmission electron microscopy. It has been frequently observed that some of iron ore crystals are damaged on exposing to the electron beam. Selected area diffraction patterns obtained from these damaged iron ore crystals have shown that iron ore crystals transform to an amorphous state.
Optical and electron microscopic observations have revealed that the small reduced iron particles, as reduction proceeds, coalesce and grow, and finally coarse iron particles are formed.View full abstractDownload PDF (1880K) -
Genjiro Mima, Toshihiro Oka, Koji Baba1968 Volume 32 Issue 10 Pages 943-949
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUnder tensile load with their boundaries aligned at 45 deg. to the tensile axis of 99.99% aluminium bicrystal specimens, observations were made on the influence of the orientation of component crystals or boundary angle on the grain boundary sliding and shear deformation near the boundary by (1) the creep test, (2) increasing stress with a constant rate, and (3) increasing temperature with a constant rate.
Final grain boundary displacements of three kinds of above-mentioned test, generally, varied linearly with the crystal orientation relationship reported by Rhines et al. However, in the case of the creep test, the deviation from the linear relationship was observed more frequently than in the others.
With increasing boundary shear stress up to 100 g/mm2 with a constant rate of 1 g/mm2/min at 350°C, grain boundary sliding of the specimens was observed at the stress range from 9.5 to 29 g/mm2, with increasing temperature up to 430°C with a constant heating rate of 2.5°C/min under the boundary shear stress of 50 g/mm2, grain boundary sliding of the specimens was observed at the temperature range from 170° to 240°C.
The values of an index of the strength of grain boundary τ0 which was reported previously by us and of the activation energy Q varied as a linear function with the angle ω measured between crystal slip directions on the slip planes of component crystals most paralled to the boundary plane of bicrystal and when the angle ω varied from 14 to 60 deg., the value of τ0 increased from 1.77×104 to 3.86×104 g/cm2, and the value of Q increased from 10500 to 25000 cal/mol.View full abstractDownload PDF (1966K) -
Toshisada Mori, Eiji Ichise1968 Volume 32 Issue 10 Pages 949-954
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA definite correlation has been found between the interaction parameters of nitrogen dissolved in liquid iron and in austenite. This correlation is represented by the following equations:
(This article is not displayable. Please see full text pdf.)
In these equations, the values of eN(1600)(X) were taken from the table of Elliott et al., and that of εN(1600)(X) were calculated from those values. Similar equations were derived by using the recommended values of Schürmann et al.,
(This article is not displayable. Please see full text pdf.)
By making use of these equations, the unknown values of the interaction parameter of nitrogen in austenite at 1200°C were evaluated.
Temperature dependence of the slope of the regression line between interaction parameters of nitrogen in liquid iron and in austenite was discussed.
The authors suggested that the analogous correlation may be applied for the interaction parameter of carbon.
The values of interaction parameter of nitrogen dissolved in austenite and its temperature dependence derived by the authors from the results of previous investigations were summarized in the appendix.View full abstractDownload PDF (1005K) -
Akira Teramae, Satoshi Kado, Yasuo Otoguro, Riichi Todoroki1968 Volume 32 Issue 10 Pages 954-959
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn an attempt to develop the better effective low-alloy steel to the sulfur dewpoint corrosion in flue gases, an investigation was made in which the effects of alloying elements on the corrosion rate in 40% sulfuric acid at 60°C were studied. Since the superior effect of copper (0.1%) in steel had already been recognized, these effects of alloying elements were investigated in the presence of copper.
According to the results of weight-loss tests with 4-hour immersion in the same solution as mentioned before, the effects of alloying elements may be classified as follows:
(1) more effective: Sb, Se, As (antimony was most effective),
(2) slightly effective: Si,
(3) little effective: Sn, Bi, Te,
(4) slight accelerating effect on corrosion: C, Mn,
(5) accelerating effect on corrosion: P, S, Ti, Mo, Cr, Ni (The corrosion rate was linear to the sulfur content, and exponential to the phosphorus content).View full abstractDownload PDF (1623K) -
Akira Teramae, Satoshi Kado, Riichi Todoroki1968 Volume 32 Issue 10 Pages 960-965
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAs mentioned in a previous report, antimony, selenium and arsenic were found to be effective elements on corrosion resistance of steel in sulfuric acid together with coppere. In order to investigate electrochemically these behaviors of antimony, selenium, arsenic and tin together with copper, the polarization characteristics of these elements were determined by the rotating electrode method in 40% sulfuric acid at 60°C.
As for the individual effect, selenium was more effective and the others were less effective than copper. Selenium inhibited both anodic and cathodic reactions. Anodic inhibition by selenium was accelerated in coexistence with copper, but cathodic reaction was little affected. Antimony and arsenic inhibited the anodic reaction. In coexistence with copper, arsenic promoted the anodic inhibition by copper, but antimony showed the combined effect with copper and inhibited both anodic and cothodic reactions. The effect of antimony was strongest for the corrosion resistance of steel in sulfuric acid. Tin had no effect on polarization characteristics.View full abstractDownload PDF (1374K) -
Akira Teramae, Satoshi Kado, Riichi Todoroki1968 Volume 32 Issue 10 Pages 965-969
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInvestigations were made on the relation between the corrosion behavior and the corrosion products of steels in 40% sulfuric acid at 60°C. The difference of effects among the alloying elements (Sb, Se, As and Sn) on corrosion products were analyzed by means of chemical analysis and X-ray diffraction. The effects of metallic ions (Sb3+, Se6+, As5+ and Sn4+) on the corrosion of Fe-0.3%Cu alloy in 40% sulfuric acid at 60°C were also investigated, and the following results were obtained.
(1) Antimony formed an intermetallic compound (Cu2Sb) together with copper in steel. This compound was concentrated in the corrosion product film, and inhibited both anodic and cathodic reactions, thus suppressing the corrosion of steel in sulfuric acid.
(2) Arsenic was effective on anodic inhibition by redeposition like copper. In this case, the combined effect with copper was not found.
(3) Selenium had both properties of antimony and arsenic and formed an intermetallic compound with copper. But the individual effect was stronger than the combined effect with copper.
(4) The effect of tin was scarecely observed even in the presence of copper.View full abstractDownload PDF (1236K) -
Tokuzou Tsujimoto1968 Volume 32 Issue 10 Pages 970-975
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe structures of Ti-4∼14%Al-2∼8%V alloys have been examined by optical microscopy after annealing for a long period in the range of 600°∼1100°C. A partial titanium-aluminium-vanadium ternary diagram for this range has been established.
To distinguish α and α2 phases, use was made of the fact that no precipitation from α2 occurs with decreasing temperature, but α2 is precipitated from α in the high aluminium alloys.
Ti-6%Al-4%V alloy is situated on the border-line for the formation of the α2 phase. Increase in aluminium or vanadium content for this alloy brings about the formation of the α2 phase.View full abstractDownload PDF (2794K) -
Eiji Isono, Tatsuru Ueno, Tateshi Udagawa1968 Volume 32 Issue 10 Pages 976-981
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn extraordinary attenuation of ultrasonic Lamb waves in mild steel sheets up to 500°C was observed, and we confirmed that it is due to the Snoek damping of carbon and/or nitrogen dissolved in the steel.
The measurement of Lamb wave attenuation has been devised more quantitatively in order to confirm the relation between the aging index and other quality of steel sheets and the internal friction.
The results are as follows:
(1) The internal friction Q−1 max by pulsed Lamb waves at 2.25 MHz of a commercial ultrasonic flaw detector is roughly equal to the total concentration of solute carbon and nitrogen atoms in the specimen following Smit’s relation.
(2) Group velocity of Lamb waves is found to be suitable as the velocity of waves to obtain Q−1.
(3) The solution of precipitated atoms, carbon and/or nitrogen, is observed when the specimen is heated above 325°C.
(4) The relation between the aging index and Q−1 max of specimens is found to be quite similar to that already reported.View full abstractDownload PDF (1635K) -
Hideo Kaneko, Tsuyoshi Murakami, Jun Ikeuchi1968 Volume 32 Issue 10 Pages 982-987
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe process of carburization is the oldest and has been most extensively employed in industry as a method of case hardening of steels. The progress in the carburization technique, however, has not been extremely rapid. Therefore a new method with higher rate of penetration and better quality of case is extensively craved for. To find a solution of this problem, electrodischarge carburization has been conducted by the present authors to combine electrodischarge heating and the carburizing action in a special electrolyte. This is a method of case hardening of steels in a electrolyte that contains the chemicals required to produce a case comparable with one resulting from liquid carburization. This provides a convenient method of carburization, with low distortion and with considerable high rate of penetration and uniformity of control of the case.
The best carburizing conditions obtained in the present study are as follows:
electrolyte: ethleneglycol saturated with sodiumchloride
applied voltage: 150 V DC
carburizing time: 1∼5 min
case depth: 0.2∼0.3 mm
hardness of the case: >Hv 850View full abstractDownload PDF (1516K) -
Yutaka Ogawa, Eihachiro Tanaka1968 Volume 32 Issue 10 Pages 988-993
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe microstructure of 99.99% silver compressed between room temperature and 800°C has been studied. The mean strain rate was 0.1∼20%/min. By using the high temperature microscope which was specially designed for the present purpose, the microstructure was observed during hot compression. The results obtained are as follows: Thermal etching of grain boundary took a long time, but when stress was applied to the specimen, grain boundary could be observed within about 1 sec. Above 400°C, grain boundary migration and sliding were observed, but recrystallized small grains were not observed. After compression above 500°C, grains were larger than before compression and they became larger with increase in compression temperature. Grain boundary migrated faster with increase in strain rate.View full abstractDownload PDF (1939K) -
Hisashi Suzuki, Takaharu Yamamoto, Hitoyuki Sakanoue1968 Volume 32 Issue 10 Pages 993-997
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe binder phase of WC-Co alloys has been thought to be the γ(fcc) phase. But, recently it was found by the present authors that a γ(fcc)→ε′(hcp) martensitic transformation occurs at low temperature under some external stresses.
In this experiment, the amount, distribution and thermal stability of the ε′ phase transformed in deformed superficial layers of the alloys by abrasion were mainly studied. The electron-micrographs of a thin film of the deformed surface including the fracture surface were also studied. The two-phase specimens containing 10∼20%Co and having the average grain size of about 1.4 μ were vacuum-sintered at 1345°∼1375°C for 1.5 hr.
The results obtained were as follows: (1) The amount of the ε′ phase increased with increasing abrasion time, and it reached a maximum constant value after the abrasion of more than 4∼5 min. (2) This maximum value increased further in the alloy having higher cobalt and carbon contents, and also in the case of abrasion by a coarser diamond wheel. (3) As for distribution of the amount of the ε′ phase from the surface to the inside, peaks were found in each alloy at the depth of about 5 μ, with the sharp decrease at the further depth. (4) A (ε′→γ) reverse transformation was observed to begin at temperatures above about 400° and 600°C in high and low carbon alloys, respectively. The transformation was completed at about 800°C in each alloy. (5) The ε′ phase formed on the abrasion or fracture surface was confirmed using transmission-electron microscope.View full abstractDownload PDF (1447K) -
Kozi Hayashi, Hisashi Suzuki, Ichiro Kawakatsu1968 Volume 32 Issue 10 Pages 997-1003
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe purpose of this experiment was to make clear the reason why WC-Co alloy is superior in the strength to other WC-Ni and WC-Fe alloys. The observation on the surface cracks and the fracture surfaces have been carried out for various cemented carbides, using optical and electron microscope, respectively. Specimens having 20% binders of Co, Ni and Fe were sintered. Their grain size was fixed at 75∼149 μ for the study of surface cracks, and at 75∼149,∼44 and 1∼2 μ for the study of fracture surfaces. Surface cracks were produced by the Vikers-indentor, and fracture surfaces, by bending-rupture. The results obtained were as follows:
(1) The following phenomena were commonly observed in each alloy having the coarrest grain size. On the portion of the surface subjected to tensile stress, initial cracks formed mainly in carbide grains, accompanied by almost no slip lines in both carbide and binder phases. On the sheared portion, however, cracks formed preferentially in the binder, with numerous slip lines in both phases of the alloys excepting WC-Fe alloy.
(2) As for the surface or interior cracks formed under tensile stress, various types of propagation were observed. In WC-Ni alloy, the propagation was very easy to occur along the carbide-binder interface; In WC-Fe alloy, along the double carbide-binder and-carbide interfaces, or through the double carbide; In WC-Co alloy, generally through the binder and scarcely along the carbide-binder interface. Therefore, the resistance to crack propagation should be largest in WC-Co alloy considering the plastic deformation of the binder, leading to the superior strength of that alloy.
(3) In WC-Co alloys, cleavage fracture of the ε′(hcp) phase, transformed from the γ(fcc) binder phase before the occurrence of fracture, was not often observed, probably due to the small amount of the ε′ phase.View full abstractDownload PDF (3064K) -
Masaiti Hori1968 Volume 32 Issue 10 Pages 1003-1007
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSWhen Al-bronze is slowly cooled, it shows a brittleness called “self-annealing phenomenon of Al-bronze”.
This phenomenon is caused by γ2 produced at β→α+γ2 transformation. Therefore the depressing of the self-annealing phenomenon poses an important problem from the engineering point of view, and it was made clear that additions of Fe and Mn are effective on the depressing of β→α+γ2 transformation.
The present study was intended to investigate the depressing effects of additions of Be and both Be and Fe on the β→α+γ2 transformation of Cu-Al alloy. For this purpose, the T.T.T. diagrams of these Cu-Al alloys were made out through examinations of microstructures. The results obtained are as follows: (1) The nose of Cu-Al-0.63Be alloy was about 462°C, 6.7×103 sec and the nose of Cu-Al-0.66Be-3.65Fe alloy was about 525°C, 1.2×103 sec. (2) Additional effects of Be and Fe on the depressing of β→α+γ2 transformation was not recognized. However, the isothermal transformation speed of Cu-Al-0.66Be-3.65Fe alloy was slightly slower than Cu-Al-3Mn alloy, and the addition of Be was effective for the depressing of β→α+γ2+κ transformation of Cu-Al-Fe alloy.View full abstractDownload PDF (1547K) -
Takashi Yasunaka, Tôru Araki, Satoshi Watanabe1968 Volume 32 Issue 10 Pages 1008-1012
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAusforming was applied to 18Ni-Co-Mo steels containing 0.002∼0.1%C. Effects of ausforming on the aging behavior, mechanical properties and microstructure with thin foil and extruction replica electron microscopy have been studied.
Disk-shaped precipitates in overaged low carbon alloys were found to have a structure close to that of Ni3Mo.
Ausforming accelerated age hardening and precipitation of Mo2C, but diminished the strength increment due to aging. In fully aged alloys, increase in 0.2% yield strength by ausforming was increased with carbon content but the trend gradually saturated beyond 0.05%C. The increasing rate of yield strength of the aged 0.1%C alloy was 0.39 kg/mm2 per % reduction above 17% reduction in thickness.
The strength of the present alloys ausformed and fully aged can be explained by the combination of ordinary strengthening and the decreased age hardening by ausforming, the primary cause of the former being the increase of dislocation density in martensite.View full abstractDownload PDF (2248K) -
Tomoo Sato, Etsujirô Yajima, Tôru Miyazaki, Shôry&uc ...1968 Volume 32 Issue 10 Pages 1013-1018
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInvestigations were carried out to clarify the influence of Mn and Ti on age-hardening behaviors of 17Cr-7Ni PH stainless steel. The results obtained are as follows:
(1) The age-hardening behavior of 17Cr-7Ni steel containing 0.9%Ti is comparable with that of the commercial 17-7 PH stainless steel containing 1.4%Al.
(2) Steel in which part of Ni is substituted with Mn and Ti is not added shows age-hardening as well.
(3) Steel containing Mn and Ti shows remarkable age-hardening due to the complex effect of the Ni-Mn precipitate and the Ni-Ti precipitate.
(4) These stainless steels are age-hardened if the matrix of the steels is martensite or delta-ferrite, while they are not hardened if it is austenite. The amount of age-hardening in the steels is roughly estimated from a special structural diagram showing the phases in the steel quenched from 1050°C and the increment of hardness due to age-hardening at 500°C for 1 hr.View full abstractDownload PDF (2331K) -
Tomoo Suzuki1968 Volume 32 Issue 10 Pages 1019-1025
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSOn the age-hardening of the Fe-Ni-Mn martensitic alloys, the hardening mechanism of the zone formation coming from a miscibility gap was proposed, and its propriety was confirmed by thermodynamic considerations. The results obtained may be summarized as follows:
(1) The hardening rate formed C curves on the reciprocal temperature-time diagram, and its nose temperature was raised as the Ni and Mn contents were concurrently increased. This result showed the existence of a solubility limit surface in the bcc phase of ternary Fe-Ni-Mn system.
(2) Under the application of Meijering’s treatment, possible combination of the energy parameters of Fe-Ni, Fe-Mn and Ni-Mn binary systems was deduced from the extent of the miscibility gap island which explained the result (1).
(3) From the equilibrium phase diagrams of Fe-Ni, Fe-Mn and Ni-Mn systems, the energy parameters for the interaction between different atoms in the bcc phase were estimated. The energy parameters of the Fe-Ni and Fe-Mn systems were nearly equal, and the Ni-Mn system showed was a larger value of negative number than them. This results satisfied the condition of (2).
(4) As the energy parameter of the Ni-Mn system had a large value of negative number, the zone rich in Ni and Mn should be ordered. It was pointed out that the ordered zone sheared by dislocations contributed to the hardening of this alloy, in addition to the hardening by the strain caused by the zone.
(5) The intense hardening response observed in the 10∼12%Ni, 5∼6%Mn alloy was interpreted in terms of the relation between the solubility line and the martensitic region.View full abstractDownload PDF (2161K) -
Toshio Katagiri, Nobujiro Takamoto1968 Volume 32 Issue 10 Pages 1025-1028
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMicroscopic examination was made on the formation of the pore in the boride layer of pure iron by gas boronizing, as it is considered as a cause of its brittleness.
By boronizing for various periods at 1000°C, it was observed that a pore was found from the initial stage of boronization, and with treating for 10 min the pore was formed all over the boride layer. With further boronization, the pore was found mostly on the boundary between the boride layer and the matrix. At the temperatures below 900°C, the pore was observed slightly in the FeB layer and not found on the boundary between the boride layer and the matrix irrespective of the boronizing time. It was found that by diffusion annealing of the boride layer, the pore did not move or form newly. By chemical analysis, Fe2+ and Fe3+ were observed in the reaction tube after boronizing.
From the above-mentioned results it was considered that the formation of the pore was not caused by the Kirkendall effect or difference in the coefficient of thermal expansion between the boride layer and the matrix,but by some chemical reaction.View full abstractDownload PDF (1806K) -
Goro Ôhira, Tamotsu Satô1968 Volume 32 Issue 10 Pages 1029-1034
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSGraphites in Ni-C and Fe-C alloys are flaky and considered to be anomalous eutectic alloys. It is of interest to compare the process of solidification of Ni-C alloy with that of Fe-C alloy, because the former is a simple binary alloy and the latter is a more complicated system with the transformation in the solid state. The Authors discovered that the graphites in Ni-C alloy were isolated and the Ni phase had not so deep grooves at the solid-liquid interface as the austenite in Fe-C alloy. Then, the growth mechanism accompanied by nucleation of graphites was considered. Nucleation in Ni-C alloy was investigated and the possibility of this mechanism was considered. The Ni phase at the solid-liquid interface had deep grooves by additions of 0.1∼0.3%S.View full abstractDownload PDF (1825K) -
Hidehiro Gotô, Minoru Hosoya1968 Volume 32 Issue 10 Pages 1035-1040
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the analysis of nitrogen in metals by the vacuum fusion or the carrier gas fusion method, lower values have generally been obtained than those of the wet method, because the surface of the melt is covered with a graphite layer deposited and the evolution of gas from the sample becomes difficult.
Therefore, we have attempted to eliminate such interference of the graphite, using the MgO lining-graphite crucible. The results of determination of nitrogen by the proposed method was in good agreement with those by the chemical method and it was confirmed that even in the case of the sample containing Al, nitrogen was quantitatively extracted without any influence of gettering.
The time required for a single determination was about 5 to 8 minutes.View full abstractDownload PDF (1769K) -
Yukio Ohba1968 Volume 32 Issue 10 Pages 1041-1042
Published: 1968
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (397K)
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