目的 解决粉末包埋渗铝过程中渗剂粘结导致渗铝层表面质量差的问题，在无惰性气体保护气氛中，在Q235钢表面制备出耐高温氧化、耐高温硫化和耐腐蚀的渗铝层。方法 采用粉末包埋渗铝法，通过改变渗剂中填充剂的成分，解决渗剂粘结导致表面质量变差的问题，研究渗铝温度、保温时间对渗层试样表面质量及渗铝层厚度的影响，确定最佳渗铝条件。使用电子显微镜观察渗铝层表面质量并测定渗铝层厚度，采用能谱仪分析渗铝层主要元素分布，采用X射线衍射仪分析渗铝层物相组成，采用显微硬度计检测渗铝层硬度变化。结果 采用成分为15%铝粉+5%氯化铵+75%氧化铝+5%石墨粉的渗剂，在无惰性气体保护下900 ℃保温4 h，获得渗铝层厚度约为370 μm的渗铝试样。渗铝层由外向内依次为铝化物层、过渡层和基体，铝化物层主要含有Al、Fe两种元素，原子百分比保持在7:3左右，主要物相为Fe2Al5，硬度达到896HV0.1，远高于基体硬度。结论 渗剂中添加适量的石墨粉能够改善渗铝层表面质量，增加渗层厚度，过多的石墨粉反而不利于表面质量改善和渗铝层厚度的增长。渗铝层厚度随渗铝温度的升高先增大后减小，与保温时间呈抛物线关系。

The work aims to overcome the short comings of poor surface quality of aluminized layer and powder boning during aluminizing process and prepare an aluminized layer resistant to high temperature oxidation，high temperature sulfurization and corrosion on the surface of Q235 steel in an atmosphere not protected by inert gas. Aluminizing by powder pack cementation was adopt to change the filler constituent of aluminizing medium to solve the problem of poor surface quality caused by bonding of aluminizing medium. The effect of aluminizing temperature and holding time on the surface quality and thickness of aluminized layer was studied to determine the best aluminizing condition. The surface quality and the thickness of the aluminized layer were observed by electron microscope. The distributions of main elements on aluminized layer were analyzed by energy spectrometer. The phase composition of aluminized layer was studied by XRD. The hardness change in the aluminized layer was detected by microhardness tester. An aluminized layer with a thickness of about 370 μm was prepared by the powder composed of 15% aluminum powder, 5% ammonium chloride, 75% alumina and 5% graphite under 900 ℃ for 4 hours in a non-protective atmosphere. The aluminized layer was aluminide layer, transition layer and matrix from outside to inside. The aluminide layer mainly contained two elements including Al and Fe and the atomic ratio remained at 7:3. The main phase was Fe2Al5 and the hardness of aluminide layer reached 896HV0.1 which was much higher than that of the substrate. Adding some graphite in the powder can improve the surface quality of the aluminized layer and increase the thickness of the layer, while excessive graphite powder is not beneficial to the improvement of surface quality and the thickness growth of aluminized layer. The thickness of the aluminized layer increases first and then decreases with the increasing of the aluminizing temperature and has a parabolic relationship with the holding time.