Magnetic Force Microscopic Description of the Structure of Glow Discharge Nitrided Layers Produced on Ni27Ti2AlMoNb Steel

2011 ◽  
Vol 172-174 ◽  
pp. 851-856
Author(s):  
Tomasz Borowski ◽  
Jerzy Jeleńkowski ◽  
Tadeusz Wierzchoń

The paper analyzes the magnetic properties and stability of austenite, athermal martensite, and deformation martensite that form in Ni27Ti2AlMoNb steel subjected to glow discharge assisted nitriding, and also of nitrogen austenite (S phase with various lattice constants) which occurs when the nitriding process is conducted below the temperature As. The analysis of these structural components and their morphology was performed using a magnetic force microscope (MFM), whereas the phase composition of the nitrided layers produced on this steel was determined by X-ray diffraction.

2017 ◽  
Vol 898 ◽  
pp. 1669-1674 ◽  
Author(s):  
Bin Shao ◽  
Bing Bing Li ◽  
Chun Hong Li ◽  
Yi Long Ma ◽  
Qiang Zheng ◽  
...  

The microstructure and the chemistry distribution of AlNiCo 9 samples were characterized by the X-ray diffraction, magnetic force microscope, field emission scanning electron microscopy and transmission electron microscope. An interface of a high Al content was formed near the FeCo-rich phases with a size of about 30 nm. S elements mainly combined with Ti to form titanium sulfide bars with the length between 70-150 μm, while S elements was not confirmed in the nanostructured FeCo-rich phase and AlNi-rich phase. Si and Nb preferably existed in the NiAl-rich phase, and a higher content Nb near the Cu precipitate boundary was observed. Moreover, the magnetic domain structure of AlNiCo 9 was also studied.


2001 ◽  
Vol 674 ◽  
Author(s):  
M. I.N. da Silva ◽  
J. C. González ◽  
M. S. Andrade

ABSTRACTIn this study, we investigated the magnetic domains of a FeMnSiNiCr stainless steel sample using Magnetic Force Microscope (MFM). We compared the magnetic patterns obtained by scanning the sample with three coated probes with different magnetic properties: Medium magnetic moment (MM), low magnetic moment (LM), and low coercivity (LC). The probe-surface separation was varied between 25 to 300 nm in order to quantify the magnetic microstructure of the sample. A simple model for the probe-sample interaction was used to interpret the contrast change as a function of the probe-surface separation. The experiment showed that the average maximum frequency decreases with the probe-surface separation and the intensity of the frequency is the strongest for the MM probe. X ray diffraction experiments were used to identify the different phases present in the sample. The X-ray diffraction experiments together with the MFM showed that α-phase islands surrounded by a γ-phase matrix are responsible for the magnetic properties of the sample.


1991 ◽  
Vol 69 (2) ◽  
pp. 277-285 ◽  
Author(s):  
Jing-Long Du ◽  
Steven J. Rettig ◽  
Robert C. Thompson ◽  
James Trotter

The synthesis of the β and γ forms of M(Ph2PO2)2 where M = Co and Mn are described and the compounds are characterized by infrared spectroscopy, differential scanning calorimetry, X-ray powder diffraction, and low-temperature (2–80 K) magnetic susceptibility studies. Single crystal X-ray diffraction studies are reported on the γ forms. Crystals of the γ forms of poly-bis(μ-diphenylphosphinato)cobalt(II) and poly-bis(μ-diphenylphosphinato)manganese(II) are isomorphous, crystallizing with 4 formula units per unit-cell in the monoclinic space group P21/c. Lattice constants are a = 8.080(2), 8.161(1), b = 23.550(6), 23.751(1), c = 11.726(3), 11.6946(6) Ǻ, and β = 92.88(2), 93.026(8)° for the Co and Mn derivatives respectively. The structures were solved by heavy atom methods and were refined by full-matrix least-squares procedures to R = 0.039 and 0.045 for 4041 and 2878 reflections with I ≥ 3σ(I), respectively. Both crystal structures consist of double phosphinate-bridged chain polymers containing tetrahedrally coordinated metal atoms: Co—O = 1.950(2)–1.963(2) Ǻ, O—Co—O = 104.81(8)–117.77(9)°, Mn—O = 2.016(3)–2.033(3) Ǻ, O—Mn—O = 103.2(1)–114.7(1)°. All four compounds exhibit antiferromagnetic coupling and magnetic susceptibilities have been analyzed according to two Heisenberg models for linear chains of metal ions with S = 3/2 for cobalt and S = 5/2 for manganese. The Weng model (with values for the Wagner and Friedberg model in parentheses) gives –J = 0.25 (0.26) cm−1 and 0.55 (0.60) cm−1 for the β and γ forms, respectively, of Co(Ph2PO2)2, and 0.34 (0.36) cm−1 and 0.17 (0.17) cm−1 for the β and γ forms, respectively, of Mn(Ph2PO2)2. Key words: crystal structure, diphenylphosphinates of cobalt(II) and manganese(II), magnetic properties.


Author(s):  
H. Q. Ye ◽  
K.Y. Hu

The precipitate in 2024 alloys containing Cu and Mg as the main strengthening elements is the S’ phase, which belongs to an orthorhombic system with the Cmcm space group and lattice constants of a=0.400 nm, b=0.923 nm and c=0.714 nm. The orientation relationships between the S’ phase and matrix were established by x-ray diffraction data as follows: [100]s’ //[100], [010]s’ //[021], [001]s’ //[01 ]. Recent HREM observations on the crystallography and morphology of the S’ phase have been reported. In this work Hr images of the S’ -matrix interface are presented with suitable resolution power.A 2024 Al alloy containing 4.43wt% Cu, 2.0wt% Mg and 0.53wt% Mn was treated at 495°C for 1h and quenched in water. Aging treatments were carried out at 190°C for 6h and 24h, respectively. Specimens were examined on the JEOL 200CX and 4000EX microscopes, the later of which has interpretable resolution of about 0.17 nm.


2020 ◽  
Vol 43 (1) ◽  
pp. 26-42 ◽  
Author(s):  
Zahra Hajian Karahroudi ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi

AbstractThis study presents a preparation of SrFe12O19– SrTiO3 nanocomposite synthesis via the green auto-combustion method. At first, SrFe12O19 nanoparticles were synthesized as a core and then, SrTiO3 nanoparticles were prepared as a shell for it to manufacture SrFe12O19–SrTiO3 nanocomposite. A novel sol-gel auto-combustion green synthesis method has been used with lemon juice as a capping agent. The prepared SrFe12O19–SrTiO3 nanocomposites were characterized by using several techniques to characterize their structural, morphological and magnetic properties. The crystal structures of the nanocomposite were investigated via X-ray diffraction (XRD). The morphology of SrFe12O19– SrTiO3 nanocomposite was studied by using a scanning electron microscope (SEM). The elemental composition of the materials was analyzed by an energy-dispersive X-ray (EDX). Magnetic properties and hysteresis loop of nanopowder were characterized via vibrating sample magnetometer (VSM) in the room temperature. Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed the molecular bands of nanoparticles. Also, the photocatalytic behavior of nanocomposites has been checked by the degradation of azo dyes under irradiation of ultraviolet light.


2020 ◽  
Vol 10 (03) ◽  
pp. 2050003
Author(s):  
M. R. Hassan ◽  
M. T. Islam ◽  
M. N. I. Khan

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.


2010 ◽  
Vol 654-656 ◽  
pp. 1106-1109
Author(s):  
Ya Qiong He ◽  
Chang Hui Mao ◽  
Jian Yang

Nanocrystalline Fe-Co alloy powders, which were prepared by high-energy mechanical milling, were nitrided under the mixing gas of NH3/H2 in the temperature range from 380°C to 510°C. X-ray diffraction (XRD) was used to analyze the grain size and reaction during the processing. The magnetic properties of the nitrided powders were measured by Vibrating Sample Magnetometer (VSM). The results show that with the appearance of Fe4N phase after nitride treatment, and the grain-size of FeCo phase decreases with the increase of nitridation temperature between 380°C to 450°C.The saturation magnetization of nitrided alloy powder treated at 480°C is about 18% higher than that of the initial Fe-Co alloy powder, accompanied by the reduction of the coercivity. Transmission electron microscope (TEM) was used, attempting to further analyze the effect of Fe4N phase on microstructure and magnetic properties of the powder mixtures.


2011 ◽  
Vol 268-270 ◽  
pp. 356-359 ◽  
Author(s):  
Wen Song Lin ◽  
C. H. Wen ◽  
Liang He

Mn, Fe doped ZnO powders (Zn0.95-xMnxFe0.05O2, x≤0.05) were synthesized by an ameliorated sol-gel method, using Zn(CH3COO)2, Mn(CH3COO)2and FeCl2as the raw materials, with the addition of vitamin C as a kind of chemical reducer. The resulting powder was subsequently compacted under pressure of 10 MPa at the temperature of 873K in vacuum. The crystal structure and magnetic properties of Zn0.95-xMnxFe0.05O2powder and bulk samples have been investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). X-ray photoelectron spectroscopy (XPS) was used to study chemical valence of manganese, iron and zinc in the samples. The x-ray diffraction (XRD) results showed that Zn0.95-xMnxFe0.05O (x≤0.05) samples were single phase with the ZnO-like wurtzite structure. No secondary phase was found in the XRD spectrum. X-ray photoelectron spectroscopy (XPS) showed that Fe and Mn existed in Zn0.95-xMnxFe0.05O2samples in Fe2+and Mn2+states. The results of VSM experiment proved the room temperature ferromagnetic properties (RTFP) of Mn, Fe co-doped ZnO samples.


Sign in / Sign up

Export Citation Format

Share Document