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Results of polymer matrix hard magnetic composite materials with particles of powdered rapid quenched Nd-Fe-B strip are presented in this paper. Influence of additional materials on magnetic, mechanical and electrical properties of composite materials was studied. The composite without additions revealed good magnetic properties. With addition of soft magnetic materials—iron, the coercive force decreased while remanence of composite was almost not influenced. The addition of steel reduces both coercive force and remanence. However addition of metallic powders improves mechanical properties of the composite materials.

The paper presents a neural network model for evaluation of the magnetic/mechanical properties and the rate of corrosive wear of the polymer matrix hard magnetic composite materials with particles of the powdered rapid quenched Nd–Fe–B strip with addition of metallic powder: iron, aluminum, CuSn10 type cast copper–tin alloy and X2CrNiMo17-12-2 high-alloy steel. Simulation approach to model the magnetic/mechanical properties in function of the chemical composition employing a neural network technique was proposed. A neural network model of corrosion wear was established based on the research results from the investigations carried out in two corrosive environments. Simulation approach to model the corrosive wear in function of the chemical composition, nature of the corrosive environment and the test duration was proposed. The obtained results indicate that the developed neural networks are able to generalize which justified using these models to the simulation of magnetic/mechanical properties and corrosive wear of hard magnetic composite materials.

This paper presents the material and technological solution which makes it possible obtaining of soft and hard magnetic composite materials: nanocrystalline material–polymer. For fabrication of composite materials the following powders were used: soft magnetic material (Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 ) and hard magnetic material (Nd 14.8 Fe 76 Co 4.95 B 4.25 ). Polymer was used as the matrix (2.5 wt.%). Advanced composite materials were compacted by the one-sided uniaxial pressing. The complex relationships among the manufacturing technology of these materials, their microstructure, as well as their mechanical and physical properties were evaluated. Materialographic examination of powders morphology and the structure of composite materials were made. Composite materials show regular distribution of magnetic powder in polymer matrix. Examination of mechanical properties shows that these materials have satisfactory compression strength. Composite materials show lower magnetic properties in comparison with magnetic powder but their geometrical form allows extending their applications. The paper shows also the possibilities of these magnetic materials application. The advantage of the bonded composite materials is their simple technology, possibility of forming their properties, lowering manufacturing costs because of no costly finishing and lowering of material losses resulting from the possibility of forming any shape. The manufacturing of composite materials greatly expand the applicable possibilities of nanocrystalline powders of magnetically hard and soft materials.

The paper presents the characteristics of the protective polymer, lacquer, and metal coatings put down onto the hard magnetic composite substrate with the polymer matrix, reinforced with the Nd–Fe–B particles with additions of metal powders. Examinations of the coatings’ structures were made with the scanning electron microscopy method. Hardness, thickness, and adhesion tests of the deposited coatings were also made. It was found out that the protective coatings are characteristic of the uniform deposition on the entire surface and of the same thickness all over their area. These coatings are characterised by a compact structure with no visible delaminations and defects. Polymer coatings demonstrate higher hardness compared to the lacquer ones. The highest hardness of 350s is characteristic of the polyester polymer coating. It was found that the highest adherence of 8.4 MPa is characteristic of the polyester–epoxy coating, whereas, the lowest adherence is displayed by the phthal-urethane coating—5.0 MPa. The paper presents also the corrosive wear of the hard magnetic composite materials with the polymer matrix, reinforced with the Nd–Fe–B particles from the rapid quenched strip, sintered Nd–Fe–B magnets, and composite materials coated with the protective polymer, lacquer, and metal coatings. The corrosive resistance values in the water environment and in the 5% NaCl solution environment were determined. It was found out that the composite magnets with the polymer matrix demonstrate better corrosive resistance than the sintered magnets; whereas, the best protection from the corrosive environment is provided by the polymer coatings. The neural network model for evaluation of the rate of corrosive wear of the polymer matrix hard magnetic composite materials with addition of metallic powder was established based on the research results from the investigations carried out in two corrosive environments. Three types of input data were used in the investigation: the contribution of the added powder, the nominal variable that defined the corrosive environment and the time duration of the test. The percentage corrosive wear of the surface was the output produced from such input data.

Investigation results of the polymer matrix hard magnetic composite materials with nanostructured particles of the powdered rapid quenched Nd–Fe–B strip are presented at this paper. The Nd–Fe–B powder was mixed with powders of iron, aluminum, CuSn10 casting copper alloy with tin, high-alloy X2CrNiMo17-12-2 steel. Epoxy resin has been used as the matrix (2.5 wt.%). The composites were unilaterally and uniaxially pressed at room temperature under the pressure of 800–900 MPa and cured afterwards for 2 h at 180 °C. The influence of the kind of addition materials on magnetic, mechanical and electrical properties of composite materials was estimated. Metallographic examination of powders morphology and the structure of composite materials, EDS and XRD analysis were made. Investigations of magnetic properties of composite materials show the influence of the addition material. It was found out that addition of soft magnetic material decreases coercive force HcB and slightly reduces remanence Br of composite. Addition of non-magnetic material decreases coercive force HcB and reduces remanence Br. The fact is that employment of an addition of a metal material powder, like iron, aluminum, CuSn10 casting alloy of copper with tin, as well as of the X2CrNiMo17-12-2 high-alloy steel causes the decrease of the magnetic properties of the composite material, yet it improves its mechanical properties. Addition of the iron powder has the biggest effect on improvement of the compressive strength, whereas the X2CrNiMo17-12-2 high-alloy steel powder has the most advantageous influence on hardness increase. Metallographic examination of the structure reveals uniform distribution of Nd–Fe–B powder in the polymer matrix, grains are irregular elongated in one direction. However, distribution of additions in the polymer matrix is regular, agglomerations of powders of aluminum, and iron have been observed. XRD analysis has identified the hard magnetic phase Nd2Fe14B.

Dynamic developments in the engineering and technology fields give reasons to increase the requirements posed to various engineering materials. Hard magnetic materials based on rare earth and transition metal compounds, in particular on the Nd2Fe14B phase, are materials with big application possibilities. Good magnetic properties of these magnets come from the intrinsic properties of intermetallic phases remanence and Curie temperature; and properties formed by the structure coercive force and maximum energy product. The paper presents the material and technological solutions, which make it possible to obtain hard magnetic composite materials from powdered rapid quenched Nd-Fe-B strip bonded by polymer matrix. The complex relationship among the manufacturing technologies of these materials, their microstructure, as well as magnetic, mechanical, physical properties and corrosion resistance were evaluated. The paper also shows the potential applications of these magnetic materials.