中文摘要：

通过热浸铝和扩散退火处理在45钢表面制备Fe-Al金属间化合物镀层。研究了镀层微观形貌、物相和显微硬度随退火温度升高的变化规律。结果表明，经700℃扩散退火处理的热浸镀铝钢，镀层与基体之间呈长舌状结合。800℃退火处理后，长舌状形貌基本消失，镀层厚度增至300μm。900-1000℃退火处理后，镀层呈连续的双层结构，与钢基体结合得更紧密。随扩散退火温度升高，镀层由富铝相Fe2Al5转变为富铁相FeAl和Fe3Al，导致镀层显微硬度降低。

英文摘要：

A Fe-Al intermetallic compound coating was prepared by hot-dip aluminizing and diffusion annealing on the surface of 45 steel. The variation of the coating＇s micromorphology, phase, and microhardness with the increasing of annealing temperature was studied. The results showed the coating of hop-dip aluminized steel exhibits a tongue-like bonding to the substrate after annealing at 700 ℃. The tongue-like morphology disappears basically and the coating thickens is increased to 300 μm after annealing at 800 ℃. The coating annealed at 900-1 000 ℃ has a continuous double-layered structure and a more strong adhesion to steel substrate. The coating transfers from aluminum-rich phase Fe2Al3 to iron-rich phases FeAl and Fe3Al with the increasing of diffusion annealing temperature, resulting in an decrease of microhardness of the coating.