Specialists discuss innovations in magnetic materials

International conference highlights Brazilian contributions to research on microstructure and magnetic properties.

By Diego Freire

Agência FAPESP – The state of the art in magnetic materials and the evolution of related technologies were discussed at the 22nd edition of the Soft Magnetic Materials Conference (SMM), hosted by the Brazilian Metallurgical, Materials & Mining Association (ABM) in São Paulo on September 13-16.

The conference is organized every two years by European industry associations. This is the first time that it has ever been held outside Europe. For Fernando Landgraf, SMM22 Conference Chair and President of the São Paulo State Technological Research Institute (IPT), the choice of venue evidences Brazil’s importance in the field.

“The Brazilian community has a significant presence in this branch of science and technology linked to magnetic materials, a field of the highest importance to industry and society in general,” Landgraf said. “For example, all electric motors use this kind of material, which is easily magnetized and demagnetized. Brazil is especially recognized worldwide for its research on the relationships between the microstructure of these materials and their magnetic properties, which are highly relevant to the development of the field.”

According to Landgraf, materials engineering expertise is key to the development of easily magnetized and demagnetized materials that generate motion with less energy dissipation, among other benefits.

“The conversion of electricity into motion by means of magnetism involves a loss of energy,” he said. “One of the challenges is making this process occur with as little energy loss as possible. Energy dissipation in magnetic materials is well studied, as is the development of new, more efficient materials for industry. This research is all the more important considering that 1% of the world’s steel is used in this kind of application. That’s 10 million metric tons of steel produced and used in electric motors every year. Brazil produces 500,000 tons per year for this purpose.”

Magnetostriction of materials

Some of the advances achieved by Brazil in the development of new magnetic materials presented at the conference include studies by the University of São Paulo’s Lorena School of Engineering (EEL-USP) to increase magnetostriction in soft materials. Magnetostriction is a property of ferromagnetic materials that causes them to change their shape or dimensions in response to an external magnetic field.

“Addition of the chemical element boron is an endeavor to increase magnetostriction. Several systems have been studied, including ferrotitanium and ferrovanadium. The idea is to understand why magnetostriction improves when materials are doped with these non-magnetic materials and, in a second stage, with boron,” said Cristina Bormio Nunes, a researcher at EEL-USP.

Nunes presented studies of ferrochrome, an alloy of iron, chrome, silicon and other elements used in the manufacturing of specialty steels, including corrosion-resistant grades with high electrical resistivity, among many others.

In researching new magnetic materials, Nunes’ group at EEL-USP adapted a system that makes magnetic measurements using mechanical forces. The project, “Construction of a force sensor using Fe-Ga and Fe-Al doped with boron”, which was supported by FAPESP, led to the development of a transducer that helps researchers to measure magnetostrictive properties and materials’ magnetization by applying compression or traction force.

The researchers are now working on miniaturization of the sensor and its encapsulation as a product.

“This enables us to develop magnetic materials that can be used as touch, force, pressure or presence sensors as well as several other types of sensors. Applications range from construction and automotive manufacturing to medicine, as in minimally invasive surgery, which requires magnetostrictive materials to handle scalpels or cameras inserted through tiny incisions,” said Mateus Botani de Souza Dias, also a researcher at EEL-USP.

Dias is working on optimization of the magnetic and mechanical properties of alloys of iron, aluminum and boron. The project, “Optimization of the piezomagnetic properties of Fe-Al-B alloys for use in force sensors”, is also supported by FAPESP.

“These studies are at the knowledge frontier and will contribute to advancement of the field internationally, which in itself justifies the choice of Brazil as the venue for SMM22 and the promotion of a more intense dialog between local researchers and the international community,” said Frank Patrick Missell from the University of Caxias do Sul (UCS).

Magneto-elastic sensors

Missell is a physics graduate of Princeton University and holds a PhD from the Massachusetts Institute of Technology (MIT), both in the United States. His specialty is developing magneto-elastic sensors with a wide range of applications, including portable devices that detect bacteria in medical samples and food.

Other participants in the conference highlighted new investment by the industry. Daniel Domingues from Aperam, a producer of stainless and electrical steel as well as nickel alloys, spoke about a new high-permeability grain-oriented electrical steel (HGO) to be launched in 2016 for use in the cores of high-efficiency transformers.

Over US$15 million will be invested in the project, which promises to offer the market a product with enhanced permeability and energy efficiency. “For the power generation and distribution sectors, that means smaller, more efficient transformers,” Domingues said.

SMM22 featured speakers and 190 scientific papers from 29 countries besides Brazil: Argentina, Austria, Belgium, Canada, Colombia, the Czech Republic, Finland, France, Germany, Ghana, Greece, Indonesia, Ireland, Italy, Japan, Mexico, Norway, Romania, Russia, Singapore, Slovakia, Slovenia, South Korea, Spain, Thailand, Turkey, the UK, Ukraine, and the USA.

Technical visits to the Magnetic Materials Laboratory of USP’s Physics Institute in the city of São Paulo and to the National Synchrotron Light Laboratory at the National Energy & Materials Research Center (CNPEM) in Campinas, São Paulo State, were organized.

For more information, visit www.abmbrasil.com.br/seminarios/smm22/2015/general-information.asp.