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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

BETO 2021 Peer Review - 1.3.2.001 - Algae Biomass Composition

Addressing critical improvements in biomass productivity and associated biochemical composition is a priority for the economic and sustainable commercial development of biofuels and bioproducts from algae. Capitalizing on pathways that integrate engineering approaches with fundamental biochemistry of photosynthetic organisms will lead to a better understanding of the complex nexus of algae growth rates, productivity and composition. This project focuses on identifying the critical factors for economic development of fuel and bioproduct technologies. Algal compositional characteristics form the foundation of robust economic and business models. This project supports that foundation by developing and validating accurate compositional methods and disseminating them to the greater community. Simultaneously, we build a deep understanding of the dynamic biochemical composition and carbon allocation for biomass value and conversion yields. A co-product portfolio developed under this project demonstrated a 30% increase in intrinsic value. Additionally, an integrated pipeline of molecular diversity mapping for product discovery with quantitative demonstration across species was deployed over the BETO algae program. The advances made here are highly relevant to BETO's multi-year program targets of reducing costs and integrating dynamic biomass composition with conversion processes to provide options for bioproducts, all leveraging the molecular diversity of algae.

algal compositional characteristics↗
DOE OSTI2012

Induction Consolidation of Thermoplastic Composites Using Smart Susceptors

This project has focused on the area of energy efficient consolidation and molding of fiber reinforced thermoplastic composite components as an energy efficient alternative to the conventional processing methods such as autoclave processing. The expanding application of composite materials in wind energy, automotive, and aerospace provides an attractive energy efficiency target for process development. The intent is to have this efficient processing along with the recyclable thermoplastic materials ready for large scale application before these high production volume levels are reached. Therefore, the process can be implemented in a timely manner to realize the maximum economic, energy, and environmental efficiencies. Under this project an increased understanding of the use of induction heating with smart susceptors applied to consolidation of thermoplastic has been achieved. This was done by the establishment of processing equipment and tooling and the subsequent demonstration of this fabrication technology by consolidating/molding of entry level components for each of the participating industrial segments, wind energy, aerospace, and automotive. This understanding adds to the nation's capability to affordably manufacture high quality lightweight high performance components from advanced recyclable composite materials in a lean and energy efficient manner. The use of induction heating with smart susceptors is a precisely controlled low energy method for the consolidation and molding of thermoplastic composites. The smart susceptor provides intrinsic thermal control based on the interaction with the magnetic field from the induction coil thereby producing highly repeatable processing. The low energy usage is enabled by the fact that only the smart susceptor surface of the tool is heated, not the entire tool. Therefore much less mass is heated resulting in significantly less required energy to consolidate/mold the desired composite components. This energy efficiency results in potential energy savings of {approx}75% as compared to autoclave processing in aerospace, {approx}63% as compared to compression molding in automotive, and {approx}42% energy savings as compared to convectively heated tools in wind energy. The ability to make parts in a rapid and controlled manner provides significant economic advantages for each of the industrial segments. These attributes were demonstrated during the processing of the demonstration components on this project.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

A review of the fabrication methods and mechanical behavior of continuous thermoplastic polymer fiber–thermoplastic polymer matrix composites

Abstract Thermoplastic polymer fiber–thermoplastic polymer matrix composites (PPCs or PRFPs), often recognized as self‐reinforced or single polymer composites, are potential candidates for future advanced polymer composites because of various advantages ( e.g., recyclability, formability, low‐cost, ultra‐lightweight, environmental friendliness, etc.). The manufacturability and mechanical behavior of these composites compared to conventional carbon‐/glass‐/aramid‐fiber‐reinforced polymers is of great interest to the composites community, but there are a limited number of studies in this area. To this end, this paper reviewed fabrication methods with different processing parameters and mechanical behavior of uni‐/multi‐directional thermoplastic PPCs featuring continuous thermoplastic polymer fibers from limited data in the literature. It was shown that most specific behaviors (normalized by density) of these materials in various loading conditions (e.g., quasi‐static tension/shear/flexure, tension‐tension fatigue, and out‐of‐plane impacting, etc.) are comparable to or better than glass‐/aramid‐fiber‐reinforced polymers. Particularly, the specific ductility in the foregoing conditions outperforms all the carbon‐/glass‐/aramid‐fiber‐reinforced polymers. Thermoplastic PPCs with remarkable performance can be achieved through several uncomplicated methods (e.g., film stacking, hot compaction, powder and solution impregnations, matrix infusion and injection molding, additive manufacturing, etc.), which have some similarities to the methods used for carbon‐/glass‐/aramid‐fiber‐reinforced polymers. Moreover, several opportunities and challenging problems of thermoplastic PPCs were summarized at the end of this review paper. Efficient solutions may require countless efforts in the composites community to further strengthen the performance and understanding of thermoplastic PPCs for wide applications in various engineering fields in the future.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Functional group effect of chemically modified microcrystalline methyl cellulose on thermoplastic polyurethane composites

Microcrystalline cellulose (MCC) is a promising bio-based filler for lightweight yet mechanically high-performance eco-polymer composites because of its low density and high biocompatibility. However, intermolecular hydrogen bonding among MCC is stronger than the polymer–filler interactions, which deteriorate the mechanical properties of the composites. Herein, we investigated the effects of functional groups on the mechanical properties of composites by scrutinizing chemically modified microcrystalline methyl cellulose (m-MMC) with three different substitution levels of hydroxyl group to hydroxypropyl (HP) group: no-, low-, and high-level substitution (HP-0, HP-low, and HP-high). The degree of HP substitution of m-MMC was quantitatively measured by CP/MAS NMR analysis. The relatively bulky HP groups interrupted the filler–filler intermolecular interactions and reduced the crystallinity and density of m-MMC, as evident from X-ray diffractometer and pycnometer data, respectively. For scalable production of the composites, the m-MMC were compounded with thermoplastic polyurethane (TPU) by a twin-screw extruder at concentrations between 0.5 and 10 wt%. Despite its low filler concentration, the toughness of m-MMC/TPU composites was remarkably enhanced, up to 28% (229.2 to 294.4 MJ/m 3 ) at 0.5 wt% loading of HP-low, owing to the enhanced polymer–filler interactions. In conclusion, the fundamental understanding on structure–property relationships will provide insights for designing of mechanically robust yet eco-friendly polymer composites.

composites↗
DOE OSTI2019

Lightweight TiC–(Fe–Al) ceramic–metal composites made in situ by pressureless melt infiltration

Lightweight ceramic–metal (cermet) composites combine stiffness and hardness with fracture toughness and ductility. TiC and Al are ideal pairs among lightweight cermet composites because of their relatively high strength-to-weight ratios, but these materials are difficult to process in solid state or with Al melt infiltration without making an aluminum carbide phase, which is detrimental to mechanical properties. Here, Fe is added to a TiC powder preform to reduce the activity of Al with TiC during Al melt infiltration and to aid in pressing TiC preforms, making a lightweight TiC–(Fe–Al) composite while avoiding other, unwanted phases. The composites are made by first pressing TiC powder mixed with Fe followed by Al melt infiltration; the result is a composite with high TiC content in a two-phase matrix, both of which are Fe–Al-based. The composite has low density, low porosity, high hardness, no detectable Al 4 C 3 phase with X-ray diffraction and retains shape well during infiltration.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Sustainable Use of Coffee Husks For Reinforcing Polyethylene Composites

The utilization of the coffee husk fiber (CHF) from the coffee industry as a reinforcing filler in the preparation of a cost-effective thermoplastic based composite was explored in this study. The chemical composition and thermal properties of the CHF were investigated and compared with those of wood fiber (WF). CHF proved to be mainly composed of cellulose, hemicellulose and lignin, and exhibited similar thermal behavior to WF. High density polyethylene (HDPE) composites with CHF loadings of from 40 to 70% were prepared using melt processing and extrusion. The processing properties, mechanical behavior, water absorption and thermal performance of these composites were investigated. The effect of maleated polyethylene (MAPE) used as a coupling agent on the composite was explored. The experimental results showed that increasing the CHF loading in the HDPE matrix resulted in an increase in the modulus and thermal properties of the composites, but resulted in poor water resistance. The addition of a 4% MAPE significantly improved the interfacial behavior of the hydrophilic lignocellulosic fiber and the hydrophobic polymer matrix.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Fiber from DDGS and Corn Grain as Alternative Fillers in Polymer Composites with High Density Polyethylene from Bio-based and Petroleum Sources

The steady increase in production of corn based ethanol fuel has dramatically increased the supply of its major co-product known as distiller’s dried grain with solubles (DDGS). Large amount of DDGS and corn flour are used as an animal feed. The elusieve process can separate DDGS or corn flour into two fractions: DDGS fraction with enhanced protein and oil content or corn flour fraction with high starch content, and hull fiber. This study investigated the feasibility of using fiber from DDGS and corn grain as alternative fillers to wood fiber in high density polyethylene (HDPE) composites made with two different sources of polymers. Two fiber loading rates of 30 and 50% were evaluated for fiber from DDGS, corn, and oak wood (control) to assess changes in various physical and mechanical properties of the composite materials. Two HDPE polymers, a bio-based HDPE made from sugarcane (Braskem), and a petroleum based HDPE (Marlex) were also compared as substrates. The biobased polymer composites with DDGS and corn fibers showed significantly lower water absorption than the Marlex composite samples. The Braskem composite with 30% DDGS fiber loading showed the highest impact resistance (80 J/m) among all the samples. The flexural properties showed no significant difference between the two HDPE composites.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Enhanced Interfacial Adhesion and Characterisation of Recycled Natural Fibre-Filled Biodegradable Green Composites

The structural, thermal, mechanical, and biodegradable properties of composite materials made from polylactide (PLA) and agricultural residues (arrowroot (Maranta arundinacea) fibre, AF) were evaluated. Melt blended glycidyl methacrylate-grafted polylactide (PLA-g-GMA) and coupling agent-treated arrowroot fibre (TAF) formed the PLA-g-GMA/TAF composite, which had better properties than the PLA/AF composite. The water resistance of the PLA-g-GMA/TAF composite was greater than that of the PLA/AF composite; the release of PLA in water from the PLA/AF and PLA-g-GMA/TAF composites indicated good biological activity. The PLA-g-GMA/TAF material had better mechanical properties than PLA/AF. This behaviour was attributed to better compatibility between the grafted polymer and TAF. The results indicated that the T{sub g} of PLA was increased by the addition of fibre, which may have improved the heat resistance of PLA. Furthermore, the mass losses following burial in soil compost indicated that both materials were biodegradable, especially at high levels of AF or TAF substitution.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Synthesis and Performance Evaluation of Unsaturated Polyester Blends of Resins and Its Application on Non-woven/Fabric Jute Fibers Reinforced Composites

The present study focuses on the generation of eco-friendly value added product by utilizing bio-based material as reinforced and matrix phase. Processing of soy and alkyd resin as matrix was carried out by utilization of soy flour and Ricinodendron heudelotii oil, followed essential modification in few inferior properties of soy flour resin by blending with alkyd resin. Separate sets of resin were prepared by maintaining 0%, 5% and 10% of alkyd resin in 100 g of soy flour resin respectively in each set to attain a comparative study on performance of prepared sets of resin blend. Subsequently, performance evaluation of polyester blends was evaluated by processing with non-woven/fabric jute fibers reinforced composites. The blend of R. heudelotii oil based alkyd and soy-flour resin in processing of composites was the noval approach of the study. The resins blend were characterized by FT–IR, viscosity and zeta potential measurements while thermo-mechanical analyses, water absorbancy and surface analyses were performed in composites. Significant increases noticed in the viscosity of blend, the blend containing 10% alkyd resin is two times more viscous compared to soy-flour resin. Furthermore, improvement in properties including water absorption, thermo-mechanical properties and better fiber-matrix interfacial adhesion of the composite could be observed. Higher glass transition temperature T{sub g} value i.e. 126.8 °C obtained for composites with 10% blend as matrix might emphasizes on increase of the degree of cross linking provided by the α-eleostearic fatty acid chain moiety. The enhancements in properties indicate extending opportunities for fiber-reinforced composites in several industries including building material, furniture, aerospace, nano etc.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Modified Magnetic and Electrical Properties of Perovskite-Spinel Multiferroic Composites

Multiferroic composite samples (1 − x) Bi{sub 0.9}Pr{sub 0.1}FeO{sub 3}–xNi{sub 0.5}Co{sub 0.5}Fe{sub 2}O{sub 4} for x = 0, 0.1, 0.2, 0.3, and 1.0 were synthesized by sol-gel auto-combustion method. Detailed investigations were made on the structural, magnetic, and electrical properties of these composites. The X-ray diffraction (XRD) patterns confirm the co-existence of perovskite BPFO and spinel ferrite NCFO without any impurity phase. The average particle size of BPFO and NCFO nanoparticles is nearly equal to 110 nm and 35 nm respectively which are confirmed by XRD and transmission electron microscopy (TEM) analysis. Structural and surface morphology are studied by scanning electron microscopy (SEM). The dielectric properties of the composites are also studied at room temperature. The saturation and remnant magnetization are found to increase with increase in NCFO weight percentage in the composites. The saturation magnetization (Ms) values are 3.38 emu/g, 8.65 emu/g, and 13.87 emu/g and coercivity (Hc) values are 936.52 Oe, 1058.12 Oe, and 1046.77 Oe for BPFO-NCFO 1, 2, and 3 composite samples respectively. The incorporation of BPFO and NCFO enhances the multiferroic properties in the present composite materials which are quite promising for applications point of view.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Relationship Between the Integrity of Lubricating Film and the Tribological Behavior on TiAl-Ag Self-Lubricating Composites

To explore the relationship between the integrity of the lubricating film and the tribological behavior of a metal matrix self-lubricating composite, the friction and wear experiments of TiAl-Ag self-lubricating composites were carried out with a ball-on-disk configuration. Besides, an approximate model was developed for analyzing the relationship based on Blau’s theory. The research results suggest that the friction and wear behavior of the TiAl-Ag self-lubricating composites changes in accordance with the formation conditions of the Ag-rich lubricating film. Specifically, the friction coefficients and wear rates of the TiAl-Ag self-lubricating composites decreased from high levels at full composite–counterface ball contact to low levels at full-film lubrication. Hence, the integrity of the lubricating film is a possible criterion for the self-lubricating property of the self-lubricating composites.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Electron Backscattered Diffraction Study of Pulse Electrodeposited Cu-Y{sub 2}O{sub 3} Composite Coating

The current investigation is an effort of correlating the grain growth, crystallographic orientation and second-phase Y{sub 2}O{sub 3} particles to the mechanical properties of the electrodeposited pure copper (Cu) and Cu-Y{sub 2}O{sub 3} coatings. Energy-dispersive spectrum and elemental mapping confirm the codeposition of Y{sub 2}O{sub 3} in the composite coating matrix, which indeed justifies the composite (Cu-Y{sub 2}O{sub 3}) coating. Both pure Cu and Cu-Y{sub 2}O{sub 3} coatings have (101) preferred orientation; however, the volume fraction is found comparatively lower in composite coating. Both microstructural and textural characterization through electron backscattered diffraction technique show significant grain refinement in case of Cu-Y{sub 2}O{sub 3} composite coating compared to pure Cu coating, and prominent 〈011〉 fiber texture is observed in case of pure Cu coating compared to composite coating. By the addition of second-phase Y{sub 2}O{sub 3} in the matrix, the 〈011〉 fiber texture is disintegrated and concentrated at ϕ{sub 1} = 37°, ϕ = 45°, ϕ{sub 2} = 0°. Despite lower volume fraction of 〈011〉 fiber texture, better mechanical properties (hardness and wear resistance) of the composite coating compared to pure Cu coating can be attributed to finer grain size, higher misorientation angle and incorporation of second-phase Y{sub 2}O{sub 3} particles.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Microstructure and Mechanical Properties of Mg{sub 2}Si/AZ91 Composites In Situ Synthesized by Using Silica Fume as the Si Source

Microstructure and mechanical properties of in situ Mg{sub 2}Si/AZ91 composites fabricated using silica fume as the Si source were investigated. The composites contained α-Mg, network Mg{sub 17}Al{sub 12}, lamellar Mg{sub 17}Al{sub 12}, coarse polygonal Mg{sub 2}Si and needle-type Mg{sub 2}Si. Mischmetal modification eliminated the coarse polygonal Mg{sub 2}Si and resulted in a decreased amount of lamellar Mg{sub 17}Al{sub 12} and refined matrix grain size. Solution and aging treatment made the network Mg{sub 17}Al{sub 12} transform into lamellar Mg{sub 17}Al{sub 12}. As the volume fraction of Mg{sub 2}Si increased, the matrix grain size decreased, the amount of Mg{sub 17}Al{sub 12} increased, and more Mg{sub 17}Al{sub 12} precipitated in grain interiors as a result of the increased Al/Mg ratio caused by increasing the amount of Mg{sub 2}Si. The tensile strength and elastic modulus were much higher for the modified composites than for the unmodified one and increased by both increasing the volume fraction of Mg{sub 2}Si and performing aging treatment. The composites failed in a quasi-cleavage fracture mode, and coarse polygonal Mg{sub 2}Si phases were responsible for the lowest ductility of the unmodified composite. The highest UTS of 291.55 MPa obtained is much higher than those reported so far by using fly ash as the Si source, indicating that silica fume is more suitable as the Si source to synthesize Mg{sub 2}Si/AZ91 composites.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Application of IR Thermography with Thermal Diffusivity Analysis for Detection of Plies Displacement in CFRP Composites

This paper presents an efficient nondestructive testing (NDT) method for detection of plies displacement in carbon fiber reinforced plastic (CFRP) composites using the active thermography technique. To assess the capability of the proposed technique for detection of plies displacement, the CFRP composite specimens with simulated fault were designed and manufactured. The IR thermography measurements were conducted using two-sided experimental arrangement. From recorded sequences of thermal images, the temperature variations versus time plots were extracted to obtain the maximum thermal contrasts. For quantitative interpretation of the results, the thermal diffusivity values for each composite material were determined and related to the fiber volume fraction. The experimental results showed that the thermal diffusivity increases with an increase of fiber volume fraction; further, the values of thermal diffusivity are specimen thickness dependent. The obtained values of thermal diffusivity varied from 1.5 × 10{sup −7} m{sup 2}/s (for 3.2 mm composite with 8.5 vol.% carbon fiber) to 2.6 × 10{sup −7} m{sup 2}/s (for 7.7 mm composite with 34.1 vol.% carbon fiber). On the basis of these results, it was concluded that the active thermography combined with thermal diffusivity analysis can be considered as a reliable NDT technique for detection of plies displacement in CFRP composites.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Manufacturing and Validation of a Novel Composite Component for Aircraft Main Landing Gear Bay

Composite materials may reduce the final weight of the aircraft structural components, in addition to improve fatigue performance and corrosion resistance. In order to achieve the optimization of air transport systems, making them increasingly sustainable, the structural design must be surely reviewed, starting to follow the “composite thinking” philosophy. The present research provides some relevant outcomes concerning the design of a composite sample for the main landing gear bay of a large commercial airplane (EASA CS25 category), within ITEMB (integrated full composite main landing gear bay concept) project, a program of Clean Sky 2 EU research framework. The most ambitious goal is to develop a new generation of lower center fuselage (LCF) with an innovative integrated landing system in the fuselage, which is considered the next frontier in the development of landing systems for medium-haul aircraft, such as the Airbus A320 aircraft family. The development of a different architecture, with the landing gear integrated within the related fuselage bay, could lead to a simplification of the whole subassembly with potential advantage in terms of construction and assembly times. Final target of the project is the manufacturing of an innovative monolithic composite structure that will replace the actual configuration (a mixed structure of metal and composite subassemblies) reducing or actually removing all the cost of assembly and increasing the production rate. This paper presents the main results of the work, introducing the main processing steps and prototype results; in the last part of the work, also some experimental tests on significant element are introduced as the first assessment of the technology readiness level that has been achieved.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Electrodeposition and Characterization of Cr-MoS{sub 2} Composite Coatings

In this study, Cr-MoS{sub 2} composite coatings were electrodeposited from conventional Cr{sup +6} baths containing different amounts of MoS{sub 2} particles and various types of surfactant (cationic and anionic). The effect of bath chemical composition on the coatings properties like their microstructure, morphology, chemical composition, corrosion behavior, surface roughness and microhardness was investigated using x-ray diffraction, scanning electron microscopy (SEM), energy-dispersive x-ray analysis, potentiodynamic polarization, electrochemical impedance spectroscopy, surface profilometry and Vickers microhardness measurement techniques, respectively. The results showed that incorporation of MoS{sub 2} particles into the composite coatings is very limited and Cr matrix with very low crystallinity will be electrodeposited at various experimental conditions. The presence of MoS{sub 2} particles in the bath (up to an optimum value) leads to the formation of the composite coatings with lower surface roughness values than that of conventional chromium coating. Although more MoS{sub 2} particles will be incorporated into the electrodeposits when the solid content of the bath increases, chromium cannot be electrodeposited from baths containing high amounts of MoS{sub 2} particles. Application of cationic surfactant promotes incorporation of particles into the Cr metallic matrix. Moreover, the presence of surfactant in the bath results in the formation of coatings with less microcracks. All the composite coatings have more hardness values than that of conventional chromium coating; maximum hardness is attributed to the coatings that were electrodeposited from baths containing no surfactant. The corrosion test results revealed that the smooth coatings containing more MoS{sub 2} particles and less microcracks exhibit more corrosion resistance than the other ones.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Compositional analysis of biomass reference materials: Results from an interlaboratory study

Biomass compositional methods are used to compare different lignocellulosic feedstocks, to measure component balances around unit operations and to determine process yields and therefore the economic viability of biomass-to-biofuel processes. Four biomass reference materials (RMs NIST 8491–8494) were prepared and characterized, via an interlaboratory comparison exercise in the early 1990s to evaluate biomass summative compositional methods, analysts, and laboratories. Having common, uniform, and stable biomass reference materials gives the opportunity to assess compositional data compared to other analysts, to other labs, and to a known compositional value. The expiration date for the original characterization of these RMs was reached and an effort to assess their stability and recharacterize the reference values for the remaining material using more current methods of analysis was initiated. We sent samples of the four biomass RMs to 11 academic, industrial, and government laboratories, familiar with sulfuric acid compositional methods, for recharacterization of the component reference values. In this work, we have used an expanded suite of analytical methods that are more appropriate for herbaceous feedstocks, to recharacterize the RMs’ compositions. We report the median values and the expanded uncertainty values for the four RMs on a dry-mass, whole-biomass basis. The original characterization data has been recalculated using median statistics to facilitate comparisons with this data. We found improved total component closures for three out of the four RMs compared to the original characterization, and the total component closures were near 100 %, which suggests that most components were accurately measured and little double counting occurred. Here, the major components were not statistically different in the recharacterization which suggests that the biomass materials are stable during storage and that additional components, not seen in the original characterization, were quantified here.

09 BIOMASS FUELS↗
DOE OSTI2021

Applications of Strain-Coupled Magnetoelectric Composites

This article deals with research, development and future directions of magnetoelectric composites for practical devices applications. In the past 20 years there has been a surge of research in the area of multiferroics (MF) and magnetoelectrics (ME) due to their potential to replace existing technologies based only on ferroelectric or ferromagnetic materials. Some of the magnetoelectric composites show exceptionally high potential in the area of magnetic field sensors, however, work remains before commercialization can be realized. The cross coupling among various ferroic parameters in magnetoelectric composites is several orders higher than single phase magetoelectrics, which make its favorable for low detection (nT or pT) magnetic field sensors. Advances in both layered structures or controlled three-dimensional matrix composites for applications as magnetoelectric nonvolatile memory elements are both required. Robust cross-coupling among various parameters with more than four logic states and its compatibility with complementary-symmetry metal–oxide–semiconductor (CMOS) technology are the main requirements for heterostructure magnetoelectric thin films. The major hurdles in the area of magnetoelectric nonvolatile memory elements are poor interfacial properties and weak magnetoelectric coupling for high density fast read and write processes. Another potential area is strained coupled magneto-electric composites where magnetostriction mediated dimensional change in the magnetic layer effectively modulate the change in the dimension of piezoelectric layers via piezostriction, which leads to a strong ME coupling where their coupling magnitude is sufficient for magnetic field sensors. Energy harvesters based on magnetoelectric composites are also intriguing concepts to capture various types of waste energy, in the form mechanical vibration, pressure, wind energy, hydrothermal and waste temperature.

36 MATERIALS SCIENCE↗