The cobalt-based amorphous alloy strip CoNiFeSiB is composed of iron, cobalt, silicon and boron. It features high magnetic permeability, low coercivity, extremely low loss, good temperature stability, a nearly zero magnetostriction coefficient, and is insensitive to mechanical stress. It can operate for a long time in harsh environments, significantly enhancing the stability and reliability of the product components. It is particularly suitable for transformers and inductors in military power supplies, replacing permalloy and ferrite.