Production of Fe-35%Co alloy (% by mass) and study of its magnetic properties.

• Grant number: 22/13657-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2023
• End date: August 31, 2023
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Cristina Bormio Nunes
• Grantee: Higor Natan Alves Ferreira
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil

Abstract

To date, there are few scientific studies published on Fe-Co alloys with lower amounts of Co than the equiatomic alloy. Everything that was developed in relation to low-Co alloys (~(27 < %Co < 35)) was done by the industry, which does not provide data from the research carried out.These Fe-Co alloys with lower amounts of Co are relevant to be studied, as they have high saturation magnetizations, high Curie temperatures and are cheaper, as they have less cobalt. Despite all these virtues, they have an important deficiency, which is a low value of magnetic permeability when compared to the equiatomic alloy with the addition of 2% of V. However, in relation to the cost, considering only the prices of raw materials, a ton of 35% Co alloy costs about 30% less than Fe-Co equiatomic alloy. The price of Co per ton is 52,000 USD, and the iron contained in iron ore 153 USD (data from 09/29/2022), that is, a savings of 7700 USD per ton.Therefore, we understand that it is important that Fe-Co alloys with a lower Co content than the equiatomic alloy are revisited and studied more in depth and in a systematic way, making the correlation of materials science/engineering with the physical properties of the material. In addition, the study of additions to these alloys that improve their permeability would also be relevant. This understanding and complementary studies may help in the future in some alloy formulation that will improve the magnetic performance of these materials. Deformability performance is also important if these materials are to be used in the form of thin sheets. Consequently, the use of these materials in electrical machines that demand high saturation magnetizations and high permeabilities will lead to greater energy efficiency, an urgent demand in a world lacking in energy. In particular, the demand for energy efficiency applies to electric cars and aircraft.For the present, the object of study is the Fe-Co alloy with 35% Co by mass. One of the reasons for this choice is that the alloy with 35% Co compared to the alloy with 30% Co that we have already studied in a previous project may have an increase in permeability with only an increase of 5% Co, as this increase causes a decrease accentuated at K1, the first anisotropic constant, which will cause the anisotropic field to decrease. The present Scientific Initiation project refers to the Fe-Co alloy without any addition, which is one of the alloys proposed to be studied in the FAPESP Individual Grant 2021/06350-0 granted to the project entitled "Development of Fe-Co alloys with addition of Ti and Cr for applications in electrical machines with high energy performance". The addition of Cr is performed to improve the ductility of the alloy and the effects of this addition on the magnetic properties of the material will be analyzed. The addition of Ti is used to increase the permeability of the alloy. But the study of the alloy without additions is fundamental to obtain the real effect of these additions on the magnetic and mechanical properties, as they will be made using the same procedure, with the same raw materials, in order to eliminate some variables, such as the composition and purity of alloys that could affect the analysis of results.