scholarly journals Development and Characterization of Field Structured Magnetic Composites

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2843
Author(s):  
Balakrishnan Nagarajan ◽  
Yingnan Wang ◽  
Maryam Taheri ◽  
Simon Trudel ◽  
Steven Bryant ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Monomer Conversion ◽  
Filler Loading ◽  
Magnetic Composites ◽  
Uv Curable ◽  
Epoxy Resin System ◽  
Out Of Plane ◽  
Combine Magnetic Field ◽  
Microstructural Morphology ◽  
Particle Alignment

Polymer composites containing ferromagnetic fillers are promising for applications relating to electrical and electronic devices. In this research, the authors modified an ultraviolet light (UV) curable prepolymer to additionally cure upon heating and validated a permanent magnet-based particle alignment system toward fabricating anisotropic magnetic composites. The developed dual-cure acrylate-based resin, reinforced with ferromagnetic fillers, was first tested for its ability to polymerize through UV and heat. Then, the magnetic alignment setup was used to orient magnetic particles in the dual-cure acrylate-based resin and a heat curable epoxy resin system in a polymer casting approach. The alignment setup was subsequently integrated with a material jetting 3D printer, and the dual-cure resin was dispensed and cured in-situ using UV, followed by thermal post-curing. The resulting magnetic composites were tested for their filler loading, microstructural morphology, alignment of the easy axis of magnetization, and degree of monomer conversion. Magnetic characterization was conducted using a vibrating sample magnetometer along the in-plane and out-of-plane directions to study anisotropic properties. This research establishes a methodology to combine magnetic field induced particle alignment along with a dual-cure resin to create anisotropic magnetic composites through polymer casting and additive manufacturing.

scholarly journals Rheology-Assisted Microstructure Control for Printing Magnetic Composites—Material and Process Development

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2143
Author(s):  
Balakrishnan Nagarajan ◽  
Martin A.W. Schoen ◽  
Simon Trudel ◽  
Ahmed Jawad Qureshi ◽  
Pierre Mertiny
Keyword(s):  
Manufacturing Process ◽  
Computer Aided Design ◽  
Quantum Interference ◽  
Permanent Magnets ◽  
Building Blocks ◽  
Magnetic Characteristics ◽  
Microstructure Control ◽  
Magnetic Composites ◽  
Uv Curable ◽  
Particle Alignment

Magnetic composites play a significant role in various electrical and electronic devices. Properties of such magnetic composites depend on the particle microstructural distribution within the polymer matrix. In this study, a methodology to manufacture magnetic composites with isotropic and anisotropic particle distribution was introduced using engineered material formulations and manufacturing methods. An in-house developed material jetting 3D printer with particle alignment capability was utilized to dispense a UV curable resin formulation to the desired computer aided design (CAD) geometry. Formulations engineered using additives enabled controlling the rheological properties and the microstructure at different manufacturing process stages. Incorporating rheological additives rendered the formulation with thixotropic properties suitable for material jetting processes. Particle alignment was accomplished using a magnetic field generated using a pair of permanent magnets. Microstructure control in printed composites was observed to depend on both the developed material formulations and the manufacturing process. The rheological behavior of filler-modified polymers was characterized using rheometry, and the formulation properties were derived using mathematical models. Experimental observations were correlated with the observed mechanical behavior changes in the polymers. It was additionally observed that higher additive content controlled particle aggregation but reduced the degree of particle alignment in polymers. Directionality analysis of optical micrographs was utilized as a tool to quantify the degree of filler orientation in printed composites. Characterization of in-plane and out-of-plane magnetic properties using a superconducting quantum interference device (SQUID) magnetometer exhibited enhanced magnetic characteristics along the direction of field structuring. Results expressed in this fundamental research serve as building blocks to construct magnetic composites through material jetting-based additive manufacturing processes.

Comparison of magnetic and microwave absorbing properties between multiwalled carbon nanotubes nanocomposite, nickel zinc ferrite nanocomposite and hybrid nanocomposite

2014 ◽  
Vol 11 (4) ◽  
pp. 317-322 ◽  
Author(s):  
L. Yu ◽  
S. Ahmad ◽  
Sivanesan Appadu ◽  
I. Kong ◽  
Mou'ad Tarawneh ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Magnetic Particles ◽  
Weight Ratio ◽  
Filler Loading ◽  
Hybrid Nanocomposite ◽  
Multiwalled Carbon ◽  
Microwave Absorbing Properties ◽  
Microwave Absorbing ◽  
Thermoplastic Natural Rubber

Three types of fillers were incorporated in the thermoplastic natural rubber by melt blending process. They are NiZn ferrite, multiwalled carbon nanotubes, and hybrid NiZn ferrite/multiwalled carbon nanotubes followed by weight ratio of 1:1. Their magnetic properties and microwave absorbing properties were investigated. The ball-milled techniques, resulted good filler dispersion in hybrid nanocomposite, proven by the matching saturation magnetization experimental values with the theory calculation. It was found that the magnetic property strongly depends on the amount of magnetic particles in the nanocomposites. The mixing of two different types of filler (multiwalled carbon nanotubes and NiZn ferrite) showed an enhancement of the microwave properties at lower filler loading.

scholarly journals From Single-Core Nanoparticles in Ferrofluids to Multi-Core Magnetic Nanocomposites: Assembly Strategies, Structure, and Magnetic Behavior

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2178
Author(s):  
Theodora Krasia-Christoforou ◽  
Vlad Socoliuc ◽  
Kenneth D. Knudsen ◽  
Etelka Tombácz ◽  
Rodica Turcu ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Magnetic Particles ◽  
Magnetic Behavior ◽  
Oxide Nanoparticles ◽  
Magnetic Characterization ◽  
Magnetic Composites ◽  
Functional Coating ◽  
High Magnetic Moment

Iron oxide nanoparticles are the basic components of the most promising magnetoresponsive nanoparticle systems for medical (diagnosis and therapy) and bio-related applications. Multi-core iron oxide nanoparticles with a high magnetic moment and well-defined size, shape, and functional coating are designed to fulfill the specific requirements of various biomedical applications, such as contrast agents, heating mediators, drug targeting, or magnetic bioseparation. This review article summarizes recent results in manufacturing multi-core magnetic nanoparticle (MNP) systems emphasizing the synthesis procedures, starting from ferrofluids (with single-core MNPs) as primary materials in various assembly methods to obtain multi-core magnetic particles. The synthesis and functionalization will be followed by the results of advanced physicochemical, structural, and magnetic characterization of multi-core particles, as well as single- and multi-core particle size distribution, morphology, internal structure, agglomerate formation processes, and constant and variable field magnetic properties. The review provides a comprehensive insight into the controlled synthesis and advanced structural and magnetic characterization of multi-core magnetic composites envisaged for nanomedicine and biotechnology.

scholarly journals Enhancing the Low-Frequency Induction Heating Effect of Magnetic Composites for Medical Applications

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 386 ◽  
Author(s):  
Ziyin Xiang ◽  
Khao-Iam Jakkpat ◽  
Benjamin Ducharne ◽  
Jean-Fabien Capsal ◽  
Jean-François Mogniotte ◽  
...  
Keyword(s):  
Induction Heating ◽  
Magnetic Particles ◽  
Varicose Veins ◽  
Local Heating ◽  
Low Frequency ◽  
Experimental Tests ◽  
Medical Applications ◽  
Magnetic Composite ◽  
Magnetic Composites ◽  
Frequency Excitation

This study aims to enhance the low-frequency induction heating (LFIH) effect in a thermoplastic polymer doped with iron oxide magnetic particles, which are promising candidates for several medical applications thanks to their confirmed biocompatibility. Two main approaches were proposed to successfully boost the heating ability; i.e., improving the magnetic concentration of the composite with higher filler content of 30 wt %, and doubling the frequency excitation after optimization of the inductor design. To test the magnetic properties of the ferromagnetic composite, a measurement of permeability as a function of temperature, frequency, and particle content was carried out. Thermal transfer based COMSOL simulations together with experimental tests have been performed, demonstrating feasibility of the proposed approach to significantly enhance the target temperature in a magnetic composite. These results are encouraging and confirmed that IH can be exploited in medical applications, especially for the treatment of varicose veins where local heating remains a true challenge.

scholarly journals Villari Effect at Low Strain in Magnetoactive Materials

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2472 ◽  
Author(s):  
Graciela Riesgo ◽  
Laura Elbaile ◽  
Javier Carrizo ◽  
Rosario Díaz Crespo ◽  
María Ángeles García ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnetic Flux ◽  
Cross Section ◽  
Magnetic Particles ◽  
Magnetic State ◽  
Soft Magnetic ◽  
Magnetic Composites ◽  
The Cross ◽  
Silicone Matrix ◽  
Villari Effect

Magnetic composites of soft magnetic FeGa particles embedded in a silicone matrix have been synthesized. The Villari effect has been studied depending on the size and concentration of the particles and on the magnetic state of the composite. The results indicate a decrease in the Villari effect when the concentration of the magnetic particles increases. These results suggest a relationship between the Villari effect and the mechanical properties of the composites. The Young’s modulus of the composites has been obtained by microindentation and their values related to the intensity and slope of the Villari signals. The results are explained on the basis that the reduction in the cross section of the composite when submitted to stress is the main origin of the variation of the magnetic flux in the Villari effect in this kind of composite. It has also been obtained that the magnetic state of the composite plays an important role in the Villari signal. When the magnetization of the composite is greater, the magnetic flux across the composite is greater too and, so, the same reduction in the cross section originates a greater Villari signal.

Influence of Particle Alignment on Thermal Diffusivity in Transformer Cores Made of Polymer Bonded Soft Magnetic Composites

2011 ◽  
Author(s):  
M. Anhalt ◽  
B. Weidenfeller
Keyword(s):  
Thermal Diffusivity ◽  
Filler Content ◽  
Filler Particle ◽  
Longitudinal Direction ◽  
Laser Flash ◽  
Perpendicular Direction ◽  
Flash Method ◽  
Soft Magnetic ◽  
Magnetic Composites ◽  
Particle Alignment

Measurements of thermal diffusivity α by laser flash method (LFA) have been performed on polypropylene-iron composites with filler particle content from 10vol.% to 70vol.% at temperatures from 305K to 410K. Experimental data of thermal diffusivity have been compared with existing mathematical models whereas best congruent fit is a model by Hashin and Shtrikman. Additionally to composites containing randomly distributed filler material, composites containing aligned particles where produced. LFA measurements where performed on samples in longitudinal and perpendicular direction of particle alignment. Values of thermal diffusivity in longitudinal direction of alignment where always higher than unaligned samples and in perpendicular direction of the alignment, respectively, with a maximum of 1.64: 1 (αlongitudinal: αunaligned) at a filler content of about 30vol.%.

Additive Manufacturing of Magnetically Loaded Polymer Composites: An Experimental Study for Process Development

2017 ◽  
Author(s):  
Balakrishnan Nagarajan ◽  
Alejandro F. Eufracio Aguilera ◽  
Ahmed Qureshi ◽  
Pierre Mertiny
Keyword(s):  
Magnetic Field ◽  
Additive Manufacturing ◽  
Polymer Composites ◽  
Magnetic Particles ◽  
Magnetic Flux Density ◽  
Droplet Deformation ◽  
Particle Settling ◽  
Droplet Stability ◽  
Particle Alignment ◽  
The Magnetic Field

Material jetting is an additive manufacturing technique that allows to produce three-dimensional solid parts without tooling and with minimum material wastage. In this context, magnetically loaded polymer composites with oriented magnetic particles are promising for many electrical and electronic applications. In this study, permanent magnet based alignment configurations were evaluated and compared in terms of different magnetic flux density using the finite element method. The particle alignment in cured droplet specimens and the stability of magnetically loaded polymer droplets deposited on a substrate were characterized for a material jetting based additive manufacturing process. Particle alignment and droplet deformation under the influence of the magnetic field was captured using real-time optical microscopy. The influence of rheological additives in controlling droplet stability in the magnetic field and mitigating particle settling were studied through experiments. The primary goal of this research was to identify parameters that facilitate high particle alignment, and material combinations that enhance droplet stability and mitigate particle settling. This fundamental research serves to enhance the understanding of processes and material behaviour for material jetting based additive manufacturing.

scholarly journals Understanding and Tailoring the Mechanical Properties of Liga Fabricated Materials

1998 ◽  
Vol 546 ◽  
Author(s):  
T. E Buchheit ◽  
T. R. Christenson ◽  
D. T. Schmale ◽  
D. A. Lavan
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Anisotropic Material ◽  
Mechanical Test ◽  
Plating Bath ◽  
Plane Anisotropy ◽  
Out Of Plane ◽  
Microstructural Morphology ◽  
Test Frame ◽  
Deposition Conditions

AbstractLIGA fabricated materials and components exhibit several processing issues affecting their metallurgical and mechanical properties, potentially limiting their usefulness for MEMS applications. For example, LIGA processing by metal electrodeposition is very sensitive to deposition conditions which causes significant processing lot variations of mechanical and metallurgical properties. Furthermore, the process produces a material with a highly textured lenticular microstructural morphology suggesting an anisotropic material response. Understanding and controlling out-of-plane anisotropy is desirable for LIGA components designed for out-of-plane flexures. Previous work by the current authors [6] focussed on results from a miniature servo-hydraulic mechanical test frame constructed for characterizing LIGA materials. Those results demonstrated microstructural and mechanical properties dependencies with plating bath current density in LIGA fabricated nickel (LIGA Ni). This presentation builds on that work and fosters a methodology for controlling the properties of LIGA fabricated materials through processing. New results include measurement of mechanical properties of LIGA fabricated copper (LIGA Cu), out-of-planeand localized mechanical property measurements using compression testing and nanoindentation of LIGA Ni and LIGA Cu.

Sign in / Sign up

Export Citation Format

Share Document