• Title/Summary/Keyword: Fe-Mn alloy

Search Result 216, Processing Time 0.029 seconds

Purification of Waste Acid and Manufacture of Complex Oxide and Mn-Ferrite Powder by Co-Roasting Process (폐산의 정제 기술 및 분무 배소법에 의한 복합 산화물과 Mn-Ferrite 분말의 제조)

  • 유재근;김정석;민병구;성낙일
    • Resources Recycling
    • /
    • v.7 no.4
    • /
    • pp.64-75
    • /
    • 1998
  • The purpose of this study is to produce high putity composite powder composed of Fe-oxide, Mn-oxide and Mn-ferrite having superior homogencity in composition and particle size distribution by co-roasting process. Binary component metal (Fe, Mn) chloride solutions were produced by dissolving mill scale and ferro-mangancse alloy in hydrochloric acid. These chloride solutions contained the impurities such as SiO$_{2}$, P, Al, Ca and Na, which were originated from the Fe/Mn source materials. The neutralization and polymeric coagulant method were adoped to refine the hydrochloric liquor. When pH is far below the isoelectric point (pH 2-3), the SiO$_{2}$ was the most effectively reduced element, while other impurities remained unchanged. By increasing pH above 3, most of the impurities could be reduced effectively due to the coprecipitation reaction. The polymeric coagulants such as poly vinyl alcohol, resin amine and ammonium molybdate were found to have no effect on the spray roaster designed by the authors. The produced oxide powders were confirmed to be mixtures of Fe-oxide, Mn-oxide and mn-ferrite. the powders were homogeneously mixed and the particle size increased sleeply with increasing co-roasting temperature.

  • PDF

Structural and Magnetic Properties of Co2MnSi Heusler Alloy Films

  • Lim, W.C.;Okamura S.;Tezuka N.;Inomata K.;Bae, J.Y.;Kim, H.J.;Kim, T.W.;Lee, T.D.
    • Journal of Magnetics
    • /
    • v.11 no.1
    • /
    • pp.8-11
    • /
    • 2006
  • Recently half-metallic full-Heusler alloy films have attracted significant interests for spintronics devices. As these alloys have been known to have a high spin polarization, very large TMR ratio is expected in magnetic tunnel junctions. Among these alloys, $Co_2MnSi$ full-Heusler alloy with a high spin polarization and a high Curie temperature is considered a good candidate as an electrode material for spintronic devices. In this study, the magnetic and structural properties of $Co_2MnSi$ Heusler alloy films were investigated. TMR characteristics of magnetic tunnel junctions with a $Co_2MnSi/SiO_2/CoFe$ structure were studied. A maximum MR ratio of 39% with $SiO_2$ substrates and 27% with MgO(100) substrates were obtained. The lower MR ratio than expectation is considered due to off-stoichiometry and atomic disorder of $Co_2MnSi$ electrode together with oxidation of the electrode layer.

High Nitrogen Steel for Core of Over-head Transmission Line (가공송전선 코아용 고질소강 연구)

  • Kim, Bong-Seo;Yoo, Kyung-Jae;Kwon, Hae-Woong;Lee, Hee-Woong;Kim, Byung-Geol
    • Proceedings of the KIEE Conference
    • /
    • 1998.07d
    • /
    • pp.1555-1557
    • /
    • 1998
  • In order to investigate the core material for over-head transmission line with non-magnetic and high strength nitrogen steel, microstructure and several basic properties of Fe-Mn-Cr-Ni-N steel have been studied. It is necessary that core material have a $\gamma$ phase to have a non-magnetic characteristics. To acquire a $\gamma$ phase, Mn, Ni and C are added as a alloying element. It was found that Fe-25Mn-16Cr-1Ni-N alloy have a stable $\gamma$ phase. The precipitate from this alloy system was $(Cr, Fe)_7C_3$. High Mn and N steel satisfies Sievert's relation that solubility of nitrogen increases with the square root of partial pressure of gas in metal-gas system and the hardness have proportional relation with nitrogen concentration.

  • PDF

Effect of Repetitive Cold Rolling and Annealing on the Superplasticity of Fe-10Mn-3.5Si Alloy (Fe-10Mn-3.5Si 합금의 초소성에 미치는 반복 냉연 및 소둔의 영향)

  • Jeong, Hyun-Bin;Choi, Seok-Won;Lee, Young-Kook
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.35 no.4
    • /
    • pp.211-219
    • /
    • 2022
  • It is known that superplastic materials with ultrafine grains have high elongation mainly due to grain boundary sliding. Therefore, in the present study we examined the influence of grain refinement, caused by a repetitive cold rolling and annealing process, on both superplastic elongation and superplastic deformation mechanism. The cold rolling and annealing process was repetitively applied up to 4 times using Fe-10Mn-3.5Si alloy. High-temperature tensile tests were conducted at 763 K with an initial strain rate of 1 × 10-3 s-1 using the specimens. The superplastic elongation increased with the number of the repetitive cold rolling and annealing process; in particular, the 4 cycled specimen exhibited the highest elongation of 372%. The primary deformation mechanism of all specimens was grain boundary sliding between recrystallized α-ferrite and reverted γ-austenite grains. The main reason for the increase in elongation with the number of the repetitive cold rolling and annealing process was the increase in fractions of fine recrystallized α-ferrite and reverted γ-austenite grains, which undergo grain boundary sliding.

Effects of Si, Mn, and Cr on the dissociation rate of $Fe_3C$. (철탄화물의 분해속도에 미치는 Si, Mn 및 Cr 의 영향)

  • Kim, Dong-Ui
    • Journal of Korea Foundry Society
    • /
    • v.5 no.3
    • /
    • pp.13-18
    • /
    • 1985
  • Decarburization phenomena were investigated at $800^{\circ}C$ by the $PH_2O/PH_2$ + Ar gas mixture in the case iron range which contains Si, Mn and Cr as an alloying elements. Dissociation of cementite in a matrix which contains graphitizer as Si begins at the carbon rich cementite dendrite arms. Several primary austenite $({\gamma})$ skeletons are surrounded by those nucleated graphite nodules, and that forms a limited area of nucleation region. Decarburization reactions at $800^{\circ}C$ in Fe-C, Fe-Mn-C and Fe-Cr-C alloy are followed by parabolic rate law under the gas mixture of $PH_2O/PH_2=0.01$ and the modified rate const. ${\kappa}$ were in the range of $1{\sim}6{\times}10^{-10}cm^2/s$.

  • PDF

Crystal structures and magnetic properties of Mn-Al-M (M=Cu, Fe) alloys (Mn-Al-M(M=Cu, Fe) 합금계의 결정구조 및 자기적 성질)

  • Choe, Won-Gyu;Go, Gwan-Yeong;Yun, Seok-Gil
    • Korean Journal of Materials Research
    • /
    • v.5 no.1
    • /
    • pp.22-35
    • /
    • 1995
  • In this study, crystal structures and magnetic properties of as-ast, annealed and rapidly solidified Mn-A1-M( M=Cu, Fe) alloys have been investigated. In $Mn_{0.56}Al_{0.44}$ alloys, the largest fraction of $\tau$ phase and values of magnetic properties was obtained in Mnl, i6Alo or alloy. And this alloy was used as the basic composition. In $Mn_{0.56-X}M_{X}Al_{0.44}$ alloys, when annealed, $\tau$- and $\beta$-Mn phase appeared at x< 0.08, $\tau$- and $\kappa$ phase at 0.10 $\leq x \leq$ 0.12 and $\kappa$- phase only at 0.15 $\leq x \leq$0.20 . When rapidly solidified, specimens showed similar phases as when annealed except that $\varepsilon$ phase appeared at x=0.04. In Mnu FexAlo 44 alloys, asyast specimens showed $\tau$-, $\beta$-Mn and $\gamma_2$- phase at x<0.08 and K and $\beta$-Mn phase at x>0.10. When rapidly solidified, Mn-Fe-Al specimens showed $\varepsilon$-, $\gamma_2$- and small amount of $\tau$- and $\kappa$ phase at x<0.08 and $\kappa$- phase only at 0.$\leq x \leq$0.20. All the alloys investigated were ferromagnetic. The Curie temperature of annealed specimens and rapidly solidified of Mno 5sAlu 44 alloy were -650K and -644K. Spontaneous magnetization( UII of annealed and rapidly solidified specimens were 40-45 (emu/g) and 50-52(emu/g), respectively. Remanent (M,) to saturation magnetization( Ms) ratio was -0.7. M, of rapidly solidified specimen was about 48(emu/g). Magnetic properties of $Mn_{0.56}Al_{0.44}$ alloys were found to be determined by the relative fraction of ferromagnetic r- and K- phase. When M= Cu and x=0.15, maximum as($\sigma_{0.0}$) was obtained by about 64.3 emu/g), and when M=Fe and x=0.15, 66.4( emu/g). The Curie temperature decreased as x increased.

  • PDF

Austenite Stability of Sintered Fe-based Alloy (철계 소결합금의 오스테나이트 안정성)

  • Choi, Seunggyu;Seo, Namhyuk;Jun, Junhyub;Son, Seung Bae;Lee, Seok-Jae
    • Journal of Powder Materials
    • /
    • v.27 no.5
    • /
    • pp.414-419
    • /
    • 2020
  • In the present study, we investigated the austenite stability of a sintered Fe-based nanocrystalline alloy. The volume fraction of austenite was measured based on the X-ray diffraction data of sintered Fe-based nanocrystalline alloys, which were prepared by high-energy ball milling and spark plasma sintering. The sintered alloy samples showed a higher volume fraction of austenite at room temperature as compared to the equilibrium volume fraction of austenite obtained using thermodynamic calculations, which resulted from the nanosized crystalline structure of the sintered alloy. It was proved that the austenite stability of the sintered Fe-based alloy increased with a rise in the amount of austenite stabilizing elements such as Mn, Ni, and C; however, it increased more effectively with a decrease in the actual grain size. Furthermore, we proposed a new equation to predict the martensite starting temperature for sintered Fe-based alloys.

Effect of Annealing Temperature on the Permeability and Magneto-Impedance Behaviors of Fe68.5Mn5Si13.5B9Nb3Cu1 Amorphous Alloy

  • Le Anh-Than;Ha, Nguyen Duy;Kim, Chong-Oh;Rhee, Jang-Roh;Chau Nguyen;Hoa Nguyen Quang;Tho Nguyen Due;Lee, Hee-Bok
    • Journal of Magnetics
    • /
    • v.11 no.1
    • /
    • pp.55-59
    • /
    • 2006
  • The effect of annealing temperature on the permeability and giant magneto-impedance (GMI) behaviors of $Fe_{68.5}Mn_{5}Si_{13.5}B_9Nb_3Cu_1$ amorphous alloy has been systematically investigated. The nanocrystalline $Fe_{68.5}Mn_{5}Si_{13.5}B_9Nb_3Cu_1$ alloys consisting of ultra-fine $(Fe,Mn)_3Si$ grains embedded in an amorphous matrix were obtained by annealing their precursor alloy at the temperature range from $500^{\circ}C\;to\;600^{\circ}C$ for 1 hour in vacuum. The permeability and GMI profiles were measured as a function of external magnetic field. It was found that the increase of both the permeability and the GMI effect with increasing annealing temperature up to $535^{\circ}C$ was observed and ascribed to the ultrasoft magnetic properties in the sample, whereas an opposite tendency was found when annealed at $600^{\circ}C$ which is due to the microstructural changes caused by high-temperature annealing. The study of temperature dependence on the permeability and GMI effect showed some insights into the nature of the magnetic exchange coupling between nanocrystallized grains through the amorphous boundaries in nanocrystalline magnetic materials.

Finite Element Analysis and Experimental Verification for the Cold-drawing of a FCC-based High Entropy Alloy (FCC계 고엔트로피 합금의 냉간 인발 유한요소해석 및 실험적 검증)

  • Cho, H.S.;Bae, S.J.;Na, Y.S.;Kim, J.H.;Lee, D.G.;Lee, K.S.
    • Transactions of Materials Processing
    • /
    • v.29 no.3
    • /
    • pp.163-171
    • /
    • 2020
  • We present a multi-step cold drawing for a non-equiatomic Co10Cr15Fe25Mn10Ni30V10 high entropy alloy (HEA) with a simple face-centered cubic (FCC) crystal structure. The distribution of strain in the cold-drawn Co10Cr15Fe25Mn10Ni30V10 HEA wires was analyzed by the finite element method (FEM). The effective strain was expected to be higher as it was closer to the surface of the wire. However, the reverse shear strain acted to cause a transition in the shear strain behavior. The critical effective strain at which the shear strain transition behavior is completely shifted was predicted to be 4.75. Severely cold-drawn Co10Cr15Fe25Mn10Ni30V10 HEA wires up to 96% of the maximum cross-sectional reduction ratio were successfully manufactured without breakage. With the assistance of electron back-scattering diffraction and transmission electron microscope analyses, the abundant deformation twins were found in the region of high effective strain, which is a major strengthening mechanism for the cold-drawn Co10Cr15Fe25Mn10Ni30V10 HEA wire.

Effect of Solution Treatment on the Microstructure and Damping Capacity of Fe-17%Mn Alloy (Fe-17%Mn 합금의 미세조직과 진동감쇠능에 미치는 용체화처리의 영향)

  • Lee, Young-Kook;Jun, Joong-Hwan;Choi, Chong-Sool
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.9 no.1
    • /
    • pp.12-18
    • /
    • 1996
  • Austenite(${\gamma}$) grain size, ${\varepsilon}$ martensite volume fraction and damping capacity of Fe-17%Mn alloy have been investigated as a function of solution treatment temperature of $600^{\circ}C$ to $1100^{\circ}C$. With increasing the solution temperature, ${\gamma}$ grain size, ${\varepsilon}$ martensite content and damping capacity are increased, while the hardness is decreased. When ${\gamma}$ grains are small, ${\varepsilon}$ plates grow in only one direction in each ${\gamma}$ grain. However, if the ${\gamma}$ grains are large in accordance with high solution treating temperature, several ${\varepsilon}$ variants with different orientations are formed and intersected each other in each ${\gamma}$ grain. In spite of small ${\varepsilon}$ martensite content, the damping capacity of the specimen which was annealed at $700^{\circ}C$, followed by subzero treatment at $-196^{\circ}C$, is almost equal to that of the specimen annealed at $1000^{\circ}C$ and subsequently quenched to room temperature. From this result it is suggested that the damping capacity of Fe-17%Mn alloy having fine ${\gamma}$ grains is mainly attributed to the movement of ${\gamma}/{\varepsilon}$ interface without the operation of other damping sources such as ${\varepsilon}/{\varepsilon}$ boundaries and stacking faults in ${\varepsilon}$ reported previously.

  • PDF