Microstructure and properties of heat treated iron powder compacts intended for ac soft magnetic applications

Magnetic core components are often made from laminated sheet steel, but they are difficult to manufacture in near net shape, resulting in large core losses at higher frequencies. In this study, the pure iron powder was treated with aqueous phosphoric acid to produce phosphate insulating layer on the surface. After drying the powder, it was mixed with 0.5wt% Zn stearate and compacted in a mold with a diameter of 20mm at 800MPa. The powder compacts were then heat treated at 500°C for 1 hour. The results showed that insulated iron powder was obtained with uniform phosphate layer by chemical reaction. With increased amount of phosphate layer, the core loss and density of compacts were decreased. It was also found that the addition of ethyl alcohol during insulating reaction resulted in improved core loss value.

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Sintering of bimodal micrometre/nanometre iron powder compacts - A master sintering curve approach

Powder Technology ◽

10.1016/j.powtec.2021.06.052 ◽

2021 ◽

Author(s):

Swathi K. Manchili ◽

Johan Wendel ◽

Eduard Hryha ◽

Lars Nyborg

Keyword(s):

Iron Powder ◽

Powder Compacts

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Effect of Substrate Plate Heating on the Microstructure and Properties of Selective Laser Melted Al-20Si-5Fe-3Cu-1Mg Alloy

Materials ◽

10.3390/ma14020330 ◽

2021 ◽

Vol 14 (2) ◽

pp. 330

Author(s):

Pan Ma ◽

Pengcheng Ji ◽

Yandong Jia ◽

Xuerong Shi ◽

Zhishui Yu ◽

...

Keyword(s):

Room Temperature ◽

Internal Stresses ◽

Test Results ◽

Laser Melting ◽

Microstructure And Properties ◽

Uniform Microstructure ◽

Heat Treated ◽

Fine Microstructure ◽

Plate Heating ◽

Substrate Plate

The Al-20Si-5Fe-3Cu-1Mg alloy was fabricated using selective laser melting (SLM). The microstructure and properties of the as-prepared SLM, post-treated SLM, and SLM with substrate plate heating are studied. The as-prepared SLM sample shows a non-uniform microstructure with four different phases: fcc-αAl, eutectic Al-Si, Al2MgSi, and δ-Al4FeSi2. With thermal treatment, the phases become coarser and the δ-Al4FeSi2 phase transforms partially to β-Al5FeSi. The sample produced with SLM substrate plate heating shows a relatively uniform microstructure without a distinct difference between hatch overlaps and track cores. Room temperature compression test results show that an as-prepared SLM sample reaches a maximum strength (862 MPa) compared to the heat-treated (524 MPa) and substrate plate heated samples (474 MPa) due to the presence of fine microstructure and the internal stresses. The reduction in strength of the sample produced with substrate plate heating is due to the coarsening of the microstructure, but the plastic deformation shows an improvement (20%). The present observations suggest that substrate plate heating can be effectively employed not only to minimize the internal stresses (by impacting the cooling rate of the process) but can also be used to modulate the mechanical properties in a controlled fashion.

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Effect of Cooling Rate on Microstructure and Properties of Heat-Treated Fe3Al Intermetallics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.3891 ◽

2011 ◽

Vol 189-193 ◽

pp. 3891-3894

Author(s):

Ya Min Li ◽

Hong Jun Liu ◽

Yuan Hao

Keyword(s):

Heat Treatment ◽

Cooling Rate ◽

Lattice Distortion ◽

Annealing Furnace ◽

Microstructure And Properties ◽

Homogenizing Annealing ◽

Heat Treated ◽

Mixed Fracture ◽

Sand Mould ◽

The Impact

The casting Fe3Al intermetallics were solidified in sodium silicate sand mould and permanent mould respectively to get different cooling rates. After heat treatment (1000°С/15 h homogenizing annealing + furnace cooling followed by 600°С/1 h tempering + oil quenching), the microstructure and properties of Fe3Al intermetallics were investigated. The results show that the heat-treated Fe3Al intermetallics at higher cooling rate has finer grained microstructure than lower cooling rate, and the lattice distortion increases due to the higher solid solubility of the elements Cr and B at higher cooling rate. The tensile strength and hardness of the Fe3Al intermetallics at higher cooling rate are slightly higher also. However, the impact power of intermetallics at higher cooling rate is 67.5% higher than that at lower cooling rate, and the impact fracture mode is also transformed from intercrystalline fracture at lower cooling rate to intercrystallin+transcrystalline mixed fracture at higher cooling rate.

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Interface Frictional Behaviour of Aluminium and Iron Powder Compacts at Room Temperature

Modeling, Synthesis and Fracture of Advanced Materials for Industrial and Medical Applications - Advanced Structured Materials ◽

10.1007/978-3-030-48161-2_7 ◽

2020 ◽

pp. 111-123

Author(s):

Pragat P. Marathe ◽

Kanhu C. Nayak ◽

Prashant P. Date ◽

Sergei Alexandrov

Keyword(s):

Iron Powder ◽

Room Temperature ◽

Powder Compacts ◽

Frictional Behaviour

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Effect of Pressure Carbonization in Carbon/Carbon Composite Process (II)

MRS Proceedings ◽

10.1557/proc-251-171 ◽

1991 ◽

Vol 251 ◽

Author(s):

H. Okamoto ◽

T. Hosomura ◽

K. Kosaka

Keyword(s):

Iron Powder ◽

Phenolic Resin ◽

Carbon Composite ◽

X Ray Diffraction ◽

Micro Structure ◽

Carbon Yield ◽

X Ray ◽

Effect Of Pressure ◽

Heat Treated ◽

Powder Addition

ABSTRACTWe have found that pressurized carbonization cause the increase of carbon yield and the improvement of micro structure In the case of pitch resin. While the effects of pressurized carbonization on phenolic resin are not obvious.In this study, carbonization and graphitization characteristics of phenolic resin were investigated experimentally. Phenolic resin specimens with and without iron powder addition were carbonized at the temperature of 650 °C under the pressure of atmospheric or 100MPa. Then each of them was heat-treated at the temperature of 1200, 1500 and 1900 °C respectively. Measurement of yield, density, x-ray diffraction and optical observation were carried out in the experiments. It is indicated from those results that pressurized carbonization of phenolic resin makes graphite crystallization progress and this effect is promoted by addition of iron powder.

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