Razvoj tehnike hitrega radiacijskega sintranja za izdelavo naprednih večkomponentnih trajnih magnetov tipa Nd-Fe-B brez izmeta in z zmanjšano vsebnostjo kritičnih surovin
Oznaka in naziv projekta
Z2-2645 Razvoj tehnike hitrega radiacijskega sintranja za izdelavo naprednih večkomponentnih trajnih magnetov tipa Nd-Fe-B brez izmeta in z zmanjšano vsebnostjo kritičnih surovin
Z2-2645 Development of rapid radiation-sintering technique for net-shape manufacture of advanced multicomponent Nd-Fe-B permanent magnets with reduced use of critical raw materials
Logotipi ARRS in drugih sofinancerjev
Projektna skupina
Vodja projekta: dr. Tomaž Tomše
Sodelujoče raziskovalne organizacije: Povezava na SICRIS
Sestava projektne skupine: Povezava na SICRIS
Vsebinski opis projekta
Magneti na osnovi redkih zemelj, predvsem Nd-Fe-B magneti, so eni izmed najbolj pomembnih materialov za moderno Evropo. Uporabljajo se v različnih napravah in so zelo pomembni za razvoj tehnologij, ki bodo omogočile prehod v nizkoogljično družbo. Prvič, električni motorji, ki uporabljajo magnete, kot so na primer vlečni motorji za električna vozila, so bolj varčni, zmogljivejši in manjši od motorjev, kjer magnetno polje ustvarjajo tuljave. Drugič, nekatere tehnologije, kot na primer vetrne turbine, ki za ustvarjanje elektrike izrabljajo obnovljive vire, tudi potrebujejo magnete za delovanje. Za pretvorbo električne energije v mehansko in obratno, so pomembni tako oblika in velikost magneta, kot tudi njegova kemijska sestava in mikrostruktura, na kar pa močno vpliva proces izdelave magneta. Široko izbiro glede oblike ponujajo plastomagneti, v zadnjem času pa se tudi pospešeno razvijajo različne dodajalne tehnologije za proizvodnjo magnetov. Vendar pa se magnetne lastnosti takšnih magnetov ne morejo kosati s povsem gostimi sintranimi magneti, ki se izdelajo s konvencionalno metalurgijo prahov. Po drugi strani pa sintranje na visoki temperaturi močno omeji izbiro oblike magneta, kar omejuje zasnovo električnih motorjev. Tudi za najbolj osnovne oblike, kot so prizme in valji, je po sintranju potrebno mehansko brušenje in žaganje. Posledica tega pa je materialni odpad, kar je nezaželeno, saj so elementi redkih zemelj na vrhu seznama kritičnih elementov, ki ga je pripravila Evropska Komisija. V tej projektni prijavi predlagam povsem nov pristop k proizvodnji visoko zmogljivih Nd-Fe-B magnetov brez izmeta. Da bi se drastično zmanjšali časi sintranja, kar je ključ do večje izbire glede oblike magneta in bolj ugodne mikrostrukture, bom razvil tehniko hitrega sintranja, ki bo temeljila na prenosu toplote preko intenzivnega toplotnega sevanja. V ta namen bom uporabil posebno vrsto elektro-uporovne peči, znano kot Spark Plasma Sintering, ki omogoča hitrosti segrevanja nekaj sto stopinj na minuto. Delovni proces bo zajemal tudi razvoj orodja za napovedovanje temperature v vzorcu. Izvedel bom študijo vpliva procesnih parametrov na nastanek mikrostrukture in magnetnih lastnosti, na podlagi rezultatov pa bom s pomočjo metode končnih elementov izdelal model za simuliranje temperature med sintranjem. Da bi izboljšal porabo kritičnih materialov, bom za namen raziskave uporabil Nd-Fe-B material, ki bo vseboval manj Nd, kot ga vsebujejo komercialni magneti. Krajši časi sintranja bodo zmanjšali rast zrn in preprečili verjetnost za nezaželene difuzijske procese, kar bo izboljšalo zmogljivost magneta pri povišanih temperaturah, kar je zelo zaželeno pri elektromotorjih. Nadaljnje, da bi zmanjšal porabo dragih dodatkov, kot je na primer disprozij, bom pripravil magnete z lokalno različnimi kemijskimi sestavami (večkomponentni magneti). V kombinaciji z izboljšano obliko magneta bom tako dosegel lastnosti, kakršnih doslej ni bilo moč doseči, kar bo predstavljalo pomemben korak k razvoju elektromotorjev in generatorjev naslednje generacije, kjer zasnova naprave ne bo več pogojena z omejeno izbiro oblike magneta.
Rare-earth permanent magnets, particularly Nd-Fe-B magnets, are some of the most crucial engineering materials necessary for modern Europe. They are used in a wide range of devices and are essential to the technologies that will facilitate the transition from a fossilfuel-based energy-and-transportation system to a low-carbon society. Firstly, permanent magnet motors like traction motors of electrical vehicles offer several advantages over induction motors where magnetic flux is generated by current-carrying copper coils, including better energy efficiency, compact size, light weight and high torque. Secondly, some of the alternative electricity-producing technologies like wind-turbine generators also rely on permanent magnets to provide magnetic field. Shape and size of the magnet, the material’s chemical composition and microstructure have been identified as extremely important for energy‑conversion applications. The freedom to tailor these parameters is limited intrinsically by the magnet manufacturing method. Polymer‑bonded magnets and, more recently, magnets produced by various emerging additive manufacturing techniques, can be produce in intricate shapes, but their overall magnetic performance cannot match the performance of fully-dense sintered magnets manufactured by conventional powder‑metallurgy methods. On the other hand, the limitations of the high-temperature sintering approach with regard to the final magnet’s geometry are a major problem for motor designers. In addition, post‑sinter machining is required even for basic geometrical forms like rectangular and cylindrical bars. This results in material waste, which is highly undesired, considering that the rare-earth elements are most critical of the EU’s Critical Raw Materials (CRMs). In this Project application, a completely novel approach to the net-shape manufacture of high-performance Nd-Fe-B magnets is proposed. To drastically reduce the sintering times, which is the key to control the final shape of the magnet, as well as to tailor the material’s microstructure, a rapid sintering technique based on the heat transfer by means of intense electromagnetic radiation in vacuum will be developed. A special type of electric resistance furnace, called Spark Plasma Sintering, that enables heating rates several hundred degrees/minute, will be used for this purpose. A part of the work process will focus on the development of a reliable tool for predicting the temperature of the sample. A comprehensive study of the effect of the process parameters on the microstructure and magnetic properties will be performed and the finite element method (FEM) will be used to create a model for simulating the temperature change during heating and predicting the development of temperature gradients in the material. The project will address several topical issues associated with NdFe-B magnets. To improve the resource efficiency, Nd-Fe-B magnetic material with a rareearth-lean composition will be considered. Reduced sintering times will minimize the grain growth and prevent undesired diffusional processes, boosting the material’s hightemperature performance, which is highly desired for motor applications. Further, magnets containing regions with different chemical compositions (multicomponent magnets) will be prepared, which will minimize the use of alloying additions such as expensive dysprosium and reduce the material costs. Combined with an optimized magnet shape, the properties of such magnets will be beyond the existing state-of-the-art and an important step towards development of the next-generation electrical motors and generators where the design of the device will no longer be constrained by the limited choice of the magnet geometry.
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Faze projekta in opis njihove realizacije
WP1. Study of the sintering parameters
WP2. Finite element modelling
WP3. Rapidly-sintered magnets with core-shell-type microstructure
WP4. Multicomponent magnets with improved geometry