42 n MATERIALS February 2026 www.drivesncontrols.com Aluminium: is it an acceptable alternative to copper windings? Record-high copper prices are prompting manufacturers in the electrical engineering sector to reassess long-held assumptions about the winding materials they use in electromagnetic components such as transformers, chokes and inductors. The sharp rise in copper costs – driven by supply shortages, geopolitical constraints and escalating demand from electrification – has made aluminium and hybrid aluminium– copper windings much more attractive than before. Engineers and procurement teams are now confronting a reality in which traditional copper-first design philosophies may no longer be economically sustainable, particularly for large-volume or cost-sensitive applications. Copper’s material advantages are well understood: excellent conductivity; favourable thermal properties; and strong mechanical resilience. These characteristics have historically justified copper’s higher price. But with global copper prices reaching unprecedented levels, the economic balance has shifted sharply. Aluminium – traditionally seen as a secondary or compromise material – is now re-entering conversations at the design stage. Its conductivity, about 60% that of copper, does require larger crosssections to achieve equivalent performance. In practical terms, this typically means a conductor with roughly 1.6 times the cross-sectional area. Yet in many designs, especially those where space is not a constraint, this increase is less restrictive than previously assumed. Engineers are realising that the decision is no longer just about electrical performance – it’s now about the sustainability of raw material costs over the lifespan of a product. The economics of manufacturing relatively large inductive components have changed faster than the technology itself. Why is aluminium gaining ground? The renewed interest in aluminium stems from several pragmatic factors: n Cost stability Even with the need for increased conductor volumes, aluminium remains much cheaper than copper. With copper prices at record highs, this gap is bigger than at any point in the past decade. n Weight benefits Aluminium’s lower density makes it especially valuable in applications where total system weight is critical – such as transportation, mobile equipment, and installations where structural loads must be reduced. n Modern joining techniques Improved mechanical terminations and surface treatments have addressed many of aluminium’s historical weaknesses, such as oxidation at connection points and concerns over long-term contact reliability. n Suitability for lower-density designs For inductors, filters and transformers operating at low to medium frequencies – particularly those with generous coil windows – aluminium’s larger cross-section is rarely a limiting factor. These considerations are now prompting design engineers to revisit winding specifications that may have gone unchanged for years. Despite the market pressures, copper’s position in certain high-performance applications remains secure. It is still the preferred choice for: n high-frequency inductors and chokes; n compact magnetic components where space is constrained; n harsh thermal environments; n precision applications; and n high-reliability sectors, such as rail traction and industrial power conversion. In these cases, copper’s conductivity and mechanical behaviour are difficult to replace As copper prices hit record highs, engineers are reassessing whether aluminium is now a more attractive option for some winding applications. Steve Hughes, managing director of REO UK, examines the pros and cons. Aluminium is challenging copper is some winding applications
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