Effect of Heat Treatment on Microstructure and Thermal Stability of Nd–Fe–B Sintered Magnets

2011 ◽  
Vol 47 (10) ◽  
pp. 3270-3272 ◽  
Author(s):  
Youhao Liu ◽  
Shuai Guo ◽  
Renjie Chen ◽  
Dong Lee ◽  
Aru Yan
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Sintered Magnets ◽  
Thermal Stability Of

scholarly journals Improvement of Thermal Stability of Nd-Tb-Fe-Co-B Sintered Magnets by Additions of Pr, Ho, Al, and Cu

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
A. A. Lukin ◽  
E. I. Il'yashenko ◽  
A. T. Skjeltorp ◽  
G. Helgesen
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Magnetic Properties ◽  
Thermal Treatment ◽  
Temperature Interval ◽  
Magnetic Parameters ◽  
Sintered Magnets ◽  
Additional Doping ◽  
As Solubility ◽  
Thermal Stability Of

The present work investigates the influence of Pr, Al, Cu, B and Ho which were introduced into the Co-containing sintered magnets of Nd-Dy-Tb-Fe-Co-B type on the magnetic parameters (α, Hci, Br, BHmax⁡). The effect of heat treatment parameters on magnetic properties was also studied. It was revealed that the essential alloying of NdFeB magnets by such elements as Dy, Tb, Ho, Co as well as by boron-forming elements, for example, by titanium, may lead to reducing of F-phase quantity, and, as a consequence, to decreasing of magnetic parameters. It was also shown that additional doping of such alloys by Pr, B, Al and Cu leads to a significant increase of the quantity of F-phase in magnets as well as solubility of the Dy, Tb, Ho and Co in it. This promotes the increase of magnetic parameters. It was possible to attain the following properties for the magnets (Nd0,15Pr0,35Tb0,25Ho0,25)15(Fe0,71Co0,29)bal ⋅ Al0,9Cu0,1B8,5 (at. %) after optimal thermal treatment {1175 K (3,6–7,2 ks) with slow (12–16 ks) cooling to 675 K and subsequently remaining at T=775 K for 3,6 ks—hardening}: Br=0,88 T, Hci=1760 kA/m, BHmax⁡=144 kJ/m3, α<|0,01|%/K in the temperature interval 223–323 K.

Thermal stability of phase-separated nanograin structure during heat treatment

2021 ◽  
Vol 875 ◽  
pp. 160055
Author(s):  
Hua Guo ◽  
Fawei Tang ◽  
Yong Liu ◽  
Zhi Zhao ◽  
Hao Lu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Thermal Stability Of

Effect of Pre-Strain Rolling on Annealing Behavior of Friction-Stir Welded AA6061-T6 Aluminum Alloy

2018 ◽  
Vol 385 ◽  
pp. 355-358 ◽  
Author(s):  
Sergey Mironov ◽  
Sergey Malopheyev ◽  
Igor Vysotskiy ◽  
Daria Zhemchuzhnikova ◽  
Rustam Kaibyshev
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Alloy ◽  
Cold Rolling ◽  
Grain Growth ◽  
Rolling Schedule ◽  
Annealing Behavior ◽  
Friction Stir ◽  
Welding Direction ◽  
Thermal Stability Of

In this work, the effect of pre-strain cold rolling on thermal stability of friction-stir welded AA6061-T6 alloy was studied. The pre-strain rolling was found to be very effective in suppression of abnormal grain growth during standard post-weld T6 heat treatment. It was also shown that the efficiency of this approach essentially depends on rolling path and the rolling along welding direction was the most effective rolling schedule.

Synthesis of Fe-rich Fe–Al nanocrystalline solid solutions using ball milling

1999 ◽  
Vol 14 (5) ◽  
pp. 1760-1770 ◽  
Author(s):  
H. G. Jiang ◽  
H. M. Hu ◽  
E. J. Lavernia
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Thermal Stability ◽  
Intermetallic Compound ◽  
Ball Milling ◽  
Microstructural Evolution ◽  
Solid Solutions ◽  
Al Alloys ◽  
Time Intervals ◽  
Thermal Stability Of

The synthesis of nanocrystalline Fe, Fe–4 wt% Al, and Fe–10 wt% Al solid solutions by SPEX ball milling has been studied. The microstructural evolution during ball milling, as well as subsequent heat treatment, has been characterized. The results demonstrate that ball milling promotes the formation of αFe–4 wt% Al and αFe–10 wt% Al solid solutions by reducing the activation energy of these alloys and generating thermal energy during this process. For Fe–10 wt% Al powders milled for various time intervals up to approximately 20 min, the FeAl intermetallic compound is formed. For alloys annealed at temperatures ranging from 600 to 1000 °C, the addition of 10 wt% Al to Fe significantly enhances the thermal stability of the nanocrystalline Fe–Al alloys. Interestingly, the addition of Al within the range of 4–10 wt% seems to have little effect on the thermal stability of these alloys annealed under the same conditions. Also, the thermal stability improves for alloys milled in air as opposed to those processed using Ar.

scholarly journals Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

2020 ◽  
Author(s):  
Lijie Qu ◽  
Zhenyu Wang ◽  
Jing Qian ◽  
Zhengbin He ◽  
Songlin Yi
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Structural Changes ◽  
Aluminum Sulfate ◽  
Treated Wood ◽  
Treatment Temperature ◽  
Chinese Fir ◽  
Heat Treated ◽  
Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

Effects of Mn and Zr Addition in 6000 Series Aluminum Alloys on the Formation of Stabilized Substructures during Hot Deformation

2016 ◽  
Vol 877 ◽  
pp. 281-289 ◽  
Author(s):  
Hiroki Tanaka ◽  
Yasunori Nagai
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Alloys ◽  
Strain Rate ◽  
Hot Deformation ◽  
Fibrous Structure ◽  
Deformation Parameters ◽  
Zr Addition ◽  
Plane Strain Compression Test ◽  
Thermal Stability Of

Thermal stability of substructures in 6000 series aluminum alloys containing Mn and Zr elements was investigated using plane-strain compression test. In order to form thermally stabilized substructures, the deformation parameters should be selected so as to correlate with kinetic precipitation during the deformation. For substructures of the alloys containing Mn and Zr elements, the substructures were stable during the heat treatment at 540 ̊C when the alloys were deformed at a temperature above 350 ̊C. The sheets rolled above 350 ̊C at a strain rate of under 3 s-1 per pass showed the fibrous structure and well developed β-fiber textures after the heat treatment at 540 ̊C. The sheets with the fibrous structure had an average Lankford value larger than one.

scholarly journals Microstructure and Thermal Stability of Transition Metal Nitrides and Borides on GaN

2000 ◽  
Vol 622 ◽  
Author(s):  
Jacek Jasiński ◽  
Eliana Kamińska ◽  
Anna Piotrowska ◽  
Adam Barcz ◽  
Marcin Zieliński
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Contact Structure ◽  
Secondary Ion Mass Spectrometry ◽  
Metal Nitrides ◽  
Transition Metal Nitrides ◽  
Transmission Electron ◽  
Secondary Ion ◽  
Thermal Stability Of

ABSTRACTMicrostructure and thermal stability of ZrN/ZrB2 bilayer deposited on GaN have been studied using transmission electron microscopy methods (TEM) and secondary ion mass spectrometry (SIMS). It has been demonstrated that annealing of the contact structure at 1100°C in N2 atmosphere does not lead to any observable metal/semiconductor interaction. In contrast, a failure of the integrity of ZrN/ZrB2 metallization at 800°C, when the heat treatment is performed in O2 ambient has been observed.

scholarly journals Thermal stability of ribosomal ribonucleic acid from baby hamster kidney cells

1966 ◽  
Vol 101 (3) ◽  
pp. 721-726 ◽  
Author(s):  
SJ Martin
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Ribonucleic Acid ◽  
Sedimentation Coefficient ◽  
Kidney Cells ◽  
Baby Hamster Kidney ◽  
Similar Treatment ◽  
Ribosomal Ribonucleic Acid ◽  
Thermal Stability Of ◽  
Baby Hamster Kidney Cells

1. RNA has been prepared from baby hamster kidney cells by extraction with a phenol-EDTA mixture and further purified by passing through a column of Sephadex G-25 that had been equilibrated with water. 2. Aging of the total RNA extracts at 4 degrees or heating at 95 degrees followed by rapid cooling caused a conversion of 28s RNA into material sedimenting in sucrose gradients at approx. 18s. 3. When heated RNA was re-extracted with phenol the sedimentation profile was not returned to that of the unheated RNA. 4. The 28s and 18s RNA fractions were collected separately from sucrose gradients by precipitation with 2vol. of ethanol and passed through a Sephadex G-25 column equilibrated with water. 5. Heat treatment of purified 28s RNA at 95 degrees caused the sedimentation coefficient to increase to approx. 40s, whereas similar treatment of 18s RNA caused no significant increase. If the RNA was heated before the Sephadex G-25 treatment the sedimentation coefficient of the 28s and 18s RNA decreased to approx. 12s and 8s. 6. Heating mixtures of purified 28s and 18s RNA at 95 degrees caused some aggregation of 18s material with the 28s fraction.

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