As the core component determining the energy efficiency and performance of amorphous alloy transformers, amorphous ribbons have become the key to breaking through the energy-saving bottleneck of traditional transformers. Different from the crystalline core materials (such as silicon steel sheets) used in conventional transformers, amorphous ribbons are a new type of magnetic material with a unique atomic structure and excellent comprehensive properties. Their emergence and application have not only promoted the technological innovation of transformers but also provided a solid material foundation for global energy conservation and carbon neutrality goals. This article focuses on revealing the core secrets of amorphous ribbons, interpreting their material composition, preparation process, and unique advantages compared with traditional core materials, and explaining why this seemingly thin ribbon can become the core driving force for the energy saving of amorphous alloy transformers.
To understand the unique advantages of amorphous ribbons, it is first necessary to clarify their material composition and structural characteristics, which are the fundamental differences between them and traditional crystalline magnetic materials. Amorphous ribbons, also known as metallic glass ribbons, are a type of thin ribbon-shaped material formed by rapidly cooling molten alloy, with an atomic structure in a disordered amorphous state—unlike the regular and ordered crystalline structure of silicon steel sheets, the atoms of amorphous ribbons are randomly distributed in the material matrix, forming a glassy homogeneous structure without grain boundaries and defects.
The material composition of amorphous ribbons used in transformers is carefully designed to optimize their magnetic and electrical properties. The most commonly used amorphous ribbons are iron-based amorphous ribbons, with the typical chemical composition of Fe78B13Si9 (2605S2 model), which is mainly composed of iron (Fe) as the base material, supplemented by boron (B) and silicon (Si) as alloying elements. Iron is the core element to ensure the magnetic properties of the ribbon, providing high magnetic permeability; boron plays a role in reducing the crystallization temperature of the alloy, facilitating the formation of an amorphous structure during rapid cooling; silicon can improve the resistivity of the material, reduce eddy current loss, and enhance the thermal stability of the ribbon. In addition, a small amount of other elements (such as copper, niobium) can be added according to specific performance requirements to further optimize the magnetic properties and mechanical properties of the ribbon. This scientific and reasonable material ratio, combined with the unique amorphous structure, lays the foundation for the excellent performance of amorphous ribbons.
The unique amorphous structure of amorphous ribbons is closely related to their advanced preparation process, which is also an important prerequisite for their advantages over traditional materials. The preparation of amorphous ribbons adopts the rapid solidification technology (also known as the melt-spinning method), which is a revolutionary process different from the preparation of silicon steel sheets. The specific process is as follows: first, the alloy materials (iron, boron, silicon, etc.) are melted in a vacuum induction furnace at a high temperature of 1300℃~1500℃ to form a uniform molten alloy; then, the molten alloy is sprayed onto the surface of a high-speed rotating copper or copper-beryllium alloy roller through a slit nozzle with a width of 0.2~0.5mm; under the action of the high-speed rotating roller (rotating speed up to 3000~5000r/min), the molten alloy is rapidly cooled at a cooling rate of 106℃/s~107℃/s, and the atoms have no time to arrange regularly to form crystals, thus solidifying into a thin ribbon with an amorphous structure.
The thickness of the prepared amorphous ribbon is usually between 20μm~30μm, which is only 1/10~1/15 of the thickness of traditional silicon steel sheets (0.35mm~0.5mm). This ultra-thin thickness, combined with the rapid solidification process, not only ensures the formation of a complete amorphous structure but also brings unique advantages to the performance of the ribbon. In contrast, the preparation of silicon steel sheets requires multiple processes such as smelting, rolling, annealing, and punching, and the crystalline structure formed during the slow cooling process will inevitably produce grain boundaries and defects, which limit the improvement of their magnetic properties. The advanced preparation process of amorphous ribbons not only simplifies the production process but also fundamentally avoids the defects of crystalline materials, making their performance far superior to traditional silicon steel sheets.
The most prominent unique advantage of amorphous ribbons is their excellent magnetic properties, which are the core reason why amorphous alloy transformers can achieve 80% lower no-load loss. Magnetic properties are the key indicators of transformer core materials, directly determining the magnitude of no-load loss. Amorphous ribbons have two key magnetic properties that are far superior to silicon steel sheets: extremely high magnetic permeability and extremely low coercivity.
Magnetic permeability refers to the ability of a material to conduct magnetic flux. The higher the magnetic permeability, the easier the material is to be magnetized, and the smaller the energy consumed during the magnetization process. The magnetic permeability of iron-based amorphous ribbons can reach 104~105 H/m, which is 10~100 times higher than that of traditional silicon steel sheets (103~104 H/m). This high magnetic permeability enables the amorphous ribbon core to be magnetized and demagnetized with extremely small energy consumption, thereby greatly reducing hysteresis loss—the main component of transformer no-load loss. In practical applications, the high magnetic permeability of amorphous ribbons can also reduce the volume and weight of the transformer core under the same magnetic flux requirement, realizing the miniaturization of transformers.
Coercivity refers to the magnetic field strength required to eliminate the residual magnetism of a material after magnetization. The lower the coercivity, the easier it is to demagnetize the material, and the smaller the energy waste caused by the reverse arrangement of magnetic domains during the alternating magnetization process. The coercivity of amorphous ribbons is only 0.5A/m~2A/m, which is 1/10~1/50 of that of silicon steel sheets (5A/m~100A/m). This extremely low coercivity means that the magnetic domains in the amorphous ribbon core can reverse and rearrange with very little energy, further reducing hysteresis loss and improving the energy efficiency of the transformer. The combination of high magnetic permeability and low coercivity makes the hysteresis loss of amorphous ribbons reduce by more than 80% compared with silicon steel sheets, laying a core foundation for the energy-saving performance of amorphous alloy transformers.
Another unique advantage of amorphous ribbons is their high resistivity, which can effectively reduce eddy current loss in transformers. Eddy current loss is another important component of transformer no-load loss, which is generated by the induced current formed in the core when alternating magnetic flux passes through the core (a conductor). The magnitude of eddy current loss is inversely proportional to the resistivity of the core material: the higher the resistivity, the more difficult it is for eddy current to form and flow, and the smaller the eddy current loss.
The resistivity of iron-based amorphous ribbons is 1.3×10-6Ω·m~1.5×10-6Ω·m, which is 2~3 times higher than that of traditional silicon steel sheets (0.5×10-6Ω·m~0.7×10-6Ω·m). This high resistivity, combined with the ultra-thin thickness of amorphous ribbons (20μm~30μm), can effectively block the formation and flow of eddy currents in the core. In contrast, the thickness of silicon steel sheets is much larger, and the resistivity is lower, so eddy current loss is more serious. According to actual test data, the eddy current loss of amorphous ribbons is only 1/5~1/10 of that of silicon steel sheets. The significant reduction of eddy current loss, together with the reduction of hysteresis loss, enables the no-load loss of amorphous alloy transformers to be reduced by 80% compared with traditional silicon steel sheet transformers, achieving a qualitative leap in energy conservation.
Amorphous ribbons also have excellent thermal stability and corrosion resistance, which ensure the long-term stable operation of amorphous alloy transformers and extend their service life. Thermal stability refers to the ability of a material to maintain its performance unchanged under long-term high-temperature operation. Amorphous ribbons have a glass transition temperature of 400℃~450℃ and a crystallization temperature of 500℃~550℃, which is much higher than the operating temperature of transformers (usually 80℃~120℃). Therefore, under the normal operating conditions of transformers, amorphous ribbons will not undergo crystallization, and their magnetic properties and electrical properties can remain stable for a long time.
In terms of corrosion resistance, the amorphous structure of amorphous ribbons is homogeneous and dense, without grain boundaries and defects that are easily corroded, so it has better corrosion resistance than crystalline materials such as silicon steel sheets. In addition, the alloying elements (such as silicon, boron) in amorphous ribbons can form a dense oxide film on the surface of the ribbon, which can effectively isolate the external air, water vapor and other corrosive media, further improving the corrosion resistance of the ribbon. This excellent corrosion resistance and thermal stability make the average service life of amorphous alloy transformers reach 20~25 years, which is 5~10 years longer than that of traditional silicon steel sheet transformers, reducing the energy consumption and resource waste caused by equipment replacement.
Compared with traditional silicon steel sheets, amorphous ribbons also have the unique advantage of low magnetostriction and low noise, which is in line with the development trend of green and low-carbon transformers. Magnetostriction refers to the phenomenon that the shape and size of a material change when it is magnetized. The magnitude of magnetostriction is directly related to the operating noise of the transformer: the greater the magnetostriction, the greater the vibration of the core during operation, and the higher the noise.
The magnetostriction coefficient of amorphous ribbons is only 10×10-6~20×10-6, which is 1/3~1/5 of that of silicon steel sheets (50×10-6~100×10-6). This low magnetostriction makes the amorphous ribbon core vibrate very slightly during operation, so the operating noise of amorphous alloy transformers is 5~10 decibels lower than that of traditional silicon steel sheet transformers. This low-noise advantage not only improves the operating environment of the transformer but also reduces noise pollution, making amorphous alloy transformers particularly suitable for applications in residential areas, hospitals, schools and other noise-sensitive places, and further enhancing their practical value.
In addition, amorphous ribbons also have the advantages of simple production process and environmental protection, which further enhances their market competitiveness. As mentioned earlier, the preparation of amorphous ribbons adopts the one-step rapid solidification technology, which simplifies the production process compared with the multi-step preparation process of silicon steel sheets, reduces the energy consumption during production, and improves the production efficiency. At the same time, the raw materials of amorphous ribbons are widely available, and the production process does not produce harmful pollutants, which is in line with the requirements of green production.
It is worth noting that although amorphous ribbons have many unique advantages, their application also has certain technical requirements. For example, amorphous ribbons are relatively brittle and have poor toughness, so they need to be handled carefully during the core stacking process to avoid damage; in addition, the amorphous ribbon core needs to be annealed at a low temperature (200℃~280℃) after preparation to eliminate internal stress and further optimize its magnetic properties. With the continuous improvement of core stacking technology and annealing technology, these technical problems have been effectively solved, and the application of amorphous ribbons in transformers has become more and more mature.
In conclusion, the amorphous ribbon, as the core material of amorphous alloy transformers, has unique advantages that traditional crystalline materials such as silicon steel sheets cannot match, including excellent magnetic properties (high magnetic permeability, low coercivity), high resistivity, excellent thermal stability and corrosion resistance, low magnetostriction and low noise, simple production process and environmental protection. These unique advantages are closely related to its scientific material composition, unique amorphous structure and advanced preparation process. It is precisely because of these advantages that amorphous ribbons can fundamentally solve the problem of high no-load loss of traditional transformers, enabling amorphous alloy transformers to achieve 80% lower no-load loss and become the first choice for energy conservation in various fields. With the continuous development of material science and technology, the performance of amorphous ribbons will be further optimized, and their application scope will be more extensive, making greater contributions to global energy conservation, emission reduction and green development.
