New Magnetic Domain Control Metal from Hitachi Can Boost Transformer Efficiency

Hitachi Metals has developed a new magnetic amorphous metal using its Metglas iron-based amorphous alloy and magnetic domain control technology that promises to bring dramatically higher efficiency to distribution transformers. The material has been named MaDC-A, an acronym for magnetic domain controlled. The new metal has a high flux density and approximately 25% lower core loss than conventional core materials, says the company.

In recent years, there has been a growing demand to cut carbon dioxide emissions as a countermeasure against global warming, creating a pressing need for energy saving. The energy efficiency standards for distribution transformers are becoming stricter in many countries, and, to comply with those standards, the development of metal core materials with a lower core loss is necessary.

The lack of a crystalline structure in the amorphous alloy causes it to have low hysteresis loss, which is energy loss that does not depend on the frequency generated when a magnetic field is applied to the core. Additionally, its thinness and high electrical resistivity create a characteristically low eddy-current loss, which is energy loss that occurs due to the eddy current generated when a DC magnetic field is applied to the core. The outcome, says Hitachi, is that a transformer made with it exhibits lower core loss than from magnetic steel sheets, commonly known as electrical steel or silicon steel, which are made of iron and silicon materials.

For over 20 years it has been recognized that core loss can be reduced by controlling magnetic domain structure, which is an area where a collection of minute magnets that exist in a ferromagnet is aligned in one direction. However, technologies that can be adapted for mass production have not been established. Hitachi says that by developing a magnetic domain structure control technology that adapts to mass production and applying it to Metglas, it has solved this issue that has plagued the industry for many years.

The company began supplying samples in March and mass production is planned to start in the first half of 2020 at the company’s Metglas Yasugi Works in Japan. For more info, see