田中 武雄

Mechanical alloying (MA) and mechanical grinding (MG) have been performed for Fe₈₆C₁₄ powders by a conventional ball-mill. MA has been carried out on a mixture of elemental iron and graphite powders and MG on a pre-alloyed iron-cementite powder. Ball-milled powders have been examined by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, ⁵⁷Fe Mössbauer spectroscopy and differential scanning calorimetry. Super-saturated solid solution of α-iron has been formed by a cold-welding of the pulverized iron particles on the MA process. By subsequent milling and/or heating, carbide has been formed from the solid solution. While, ultra-fine structure with capital size of few nano-meter has been formed for MG powder of the white cast iron. Amorphous phase has been formed by both MA and MG.

Mechanical alloying (MA) has been performed for a mixture of elemental iron and graphite powders by the conventional type ball-mill. Solid state reaction of Fe₃C formation has been studied for Fe₈₃C₁₇, Fe₇₅C₂₅ and Fe₇₁C₂₉ powders by transmission electron microscopy, X-ray diffractometry, ⁵⁷Fe Mössbauer spectroscopy and differential scanning calorimetry. The amorphous phase coexistent with α-Fe has been formed after 200 hour MA. After subsequent milling, these phases have been transformed into Fe₃C carbide through Fe₇C₃-like carbide. While, the successive reaction from Fe₅C₂ to Fe₃C has been also confirmed in the process of heating the amorhous phase coexistent with α-Fe.

Mechanical alloying (MA) and mechanical grinding (MG) have been performed for Fe₈₆C₁₄ powders by a conventional ball-mill. MA has been carried out on a mixture of elemental iron and graphite powders and MG on a pre-alloyed iron-cementite powder. Ball-milled powders have been examined by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, ⁵⁷Fe Mössbauer spectroscopy and differential scanning calorimetry. Super-saturated solid solution of α-iron has been formed by a cold-welding of the pulverized iron particles on the MA process. By subsequent milling and/or heating, carbide has been formed from the solid solution. While, ultra-fine structure with capital size of few nano-meter has been formed for MG powder of the white cast iron. Amorphous phase has been formed by both MA and MG.

Mechanical alloying (MA) of nickel and graphite powders was performed in the composition range Ni1-xCx (x = 0.10 to 0.90) by use of a conventional ball mill. The structure of mechanically alloyed samples was examined by X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and differential scanning calorimetry. A remarkable supersaturation of carbon in face-centered cubic (fcc) nickel phase was observed. A metastable phase Ni3C was formed by a prolonged MA treatment. For the purpose of comparative study, MA of cobalt and graphite powders was also performed in composition Co1-xCx (x = 0.10, 0.15, and 0.30). The supersaturation of carbon in fcc cobalt and formation of a metastable carbide Co3C were confirmed.

Mechanical alloying (MA) for Fe-C-Si mixtures of elemental powders was performed by a conventional ball-mill under an argon gas atmosphere. The phase formation on the ball-milling process was studied by X-ray diffractometry and differential scanning calorimetry. An addition of silicon suppressed the formation of iron-carbides to promote the amorphization. For high silicon concentration, intermetallic compounds such as FeSi,.A-FeSi2 and SiC were formed after indicating the partial amorphous formation. The inhomogeneous reaction, the slow reaction, which is a characteristic in MA of metal-nonmetal systems, was confirmed for Fe-C-Si system. © 1992, Japan Society of Powder and Powder Metallurgy. All rights reserved.

Mechanical alloying (MA) for Fe-C-Si mixtures of elemental powders was performed by a conventional ball-mill under an argon gas atmosphere. The phase formation on the ball-milling process was studied by X-ray diffractometry and differential scanning calorimetry. An addition of silicon suppressed the formation of iron-carbides to promote the amorphization. For high silicon concentration, intermetallic compounds such as FeSi,.A-FeSi2 and SiC were formed after indicating the partial amorphous formation. The inhomogeneous reaction, the slow reaction, which is a characteristic in MA of metal-nonmetal systems, was confirmed for Fe-C-Si system. © 1992, Japan Society of Powder and Powder Metallurgy. All rights reserved.

Mechanical alloying of iron and graphite powders was performed in composition range Fe(1-x)C(x) (x = 0.17-0.90) by the use of a conventional ball mill. The structures of mechanically alloyed samples were examined by X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy, Fe-57 Mossbauer spectroscopy and differential scanning calorimetry. The results from X-ray, TEM and Mossbauer measurements suggested the partial formation of amorphous phase. Amorphization was notable on the sample ball milled for about 200 h. After subsequent milling, formation of metastable carbides Fe3C for the powders with x = 0.17-0.25 and Fe7C3 for x = 0.29-0.70 was detected. Formation of fine paramagnetic particles was detected by Mossbauer spectroscopy for the powders having carbon content x = 0.80-0.90.

Mechanical alloying of iron and graphite powders was performed in composition range Fe(1-x)C(x) (x = 0.17-0.90) by the use of a conventional ball mill. The structures of mechanically alloyed samples were examined by X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy, Fe-57 Mossbauer spectroscopy and differential scanning calorimetry. The results from X-ray, TEM and Mossbauer measurements suggested the partial formation of amorphous phase. Amorphization was notable on the sample ball milled for about 200 h. After subsequent milling, formation of metastable carbides Fe3C for the powders with x = 0.17-0.25 and Fe7C3 for x = 0.29-0.70 was detected. Formation of fine paramagnetic particles was detected by Mossbauer spectroscopy for the powders having carbon content x = 0.80-0.90.

Mechanical alloying (MA) and mechanical grinding (MG) for Fe-C and Fe-C-Si systems have been performed by the use of a conventional ball-mill. Elemental powders and cast iron powders have been used for MA and MG, respectively. Phases formed on the ball-milling process has been studied by X-ray diffractometry, 57Fe Mbssbauer spectroscopy, transmission electron microscopy, scanning electron microscopy and differential scanning calorimetry.<BR>Results suggest that the partial amorphization of Fe-C system ball-milled for 200 hours has been occurred, while the single amorphous phase has been formed for Fe-C-Si system. The addition of silicon suppresses the formation of iron-carbides to promote the amorphization.

Mechanical alloying (MA) and mechanical grinding (MG) for Fe-C and Fe-C-Si systems have been performed by the use of a conventional ball-mill. Elemental powders and cast iron powders have been used for MA and MG, respectively. Phases formed on the ball-milling process has been studied by X-ray diffractometry, 57Fe Mbssbauer spectroscopy, transmission electron microscopy, scanning electron microscopy and differential scanning calorimetry.<BR>Results suggest that the partial amorphization of Fe-C system ball-milled for 200 hours has been occurred, while the single amorphous phase has been formed for Fe-C-Si system. The addition of silicon suppresses the formation of iron-carbides to promote the amorphization.

Mechanical alloying (MA) and mechanical grinding (MG) for Fe-C and Fe-C-Si systems have been performed by the use of a conventional ball-mill. Elemental powders and cast iron powders have been used for MA and MG, respectively. Phases formed on the ball-milling process has been studied by X-ray diffractometry, 57Fe Mbssbauer spectroscopy, transmission electron microscopy, scanning electron microscopy and differential scanning calorimetry.<BR>Results suggest that the partial amorphization of Fe-C system ball-milled for 200 hours has been occurred, while the single amorphous phase has been formed for Fe-C-Si system. The addition of silicon suppresses the formation of iron-carbides to promote the amorphization.

Mechanical alloying (MA) of iron and graphite powders has been performed using a conventional ball-mill. MA process of Fe₁-xCx (x=0.17-0.90) powders has been studied by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, 57Fe Mössbauer spectroscopy and differential scanning calorimetry.<BR>Results from X-ray diffraction and 57Fe Mbssbauer measurement suggest the formation of amorphous phase in powders ball-milled for about 200 hours. After subsequently long milling periods like 1000 hours, the formation of metastable carbides of Fe₃C and Fe₇C₃ has been detected for the powders of x=0.17-0.25 and x=0.29-0.70. Formation of super-paramagnetic Fe-C particles at room temperature has been detected by Mössbauer spectroscopy for the powders having a higher carbon content like x=0.90.

Mechanical alloying (MA) of iron and graphite powders has been performed using a conventional ball-mill. MA process of Fe₁-xCx (x=0.17-0.90) powders has been studied by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, 57Fe Mössbauer spectroscopy and differential scanning calorimetry.<BR>Results from X-ray diffraction and 57Fe Mbssbauer measurement suggest the formation of amorphous phase in powders ball-milled for about 200 hours. After subsequently long milling periods like 1000 hours, the formation of metastable carbides of Fe₃C and Fe₇C₃ has been detected for the powders of x=0.17-0.25 and x=0.29-0.70. Formation of super-paramagnetic Fe-C particles at room temperature has been detected by Mössbauer spectroscopy for the powders having a higher carbon content like x=0.90.

Mechanical alloying (MA) of iron and graphite powders has been performed using a conventional ball-mill. MA process of Fe₁-xCx (x=0.17-0.90) powders has been studied by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, 57Fe Mössbauer spectroscopy and differential scanning calorimetry.<BR>Results from X-ray diffraction and 57Fe Mbssbauer measurement suggest the formation of amorphous phase in powders ball-milled for about 200 hours. After subsequently long milling periods like 1000 hours, the formation of metastable carbides of Fe₃C and Fe₇C₃ has been detected for the powders of x=0.17-0.25 and x=0.29-0.70. Formation of super-paramagnetic Fe-C particles at room temperature has been detected by Mössbauer spectroscopy for the powders having a higher carbon content like x=0.90.