目的 制备一种新型复合防腐涂层，增强316L不锈钢在中高温硫酸溶液中的耐蚀性。方法 首先使用化学氧化法在石墨(G)颗粒表面原位聚合聚苯胺(PANI)，制得PANI/G复合材料，再使用环氧树脂(EP)作为粘结剂，制备PANI/G/EP复合涂层。对比了PANI/G/EP复合涂层与PANI/EP复合涂层及添加氧化石墨烯(GO)制备的PANI/GO/EP复合涂层的电化学性能、附着力、导电性以及对应复合材料的导电性，同时探究了石墨与聚苯胺比例对PANI/G/EP复合涂层电化学性能的影响。通过傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)以及X射线能谱(EDS)等手段对PANI/G复合材料与PANI/G/EP复合涂层的化学键合与微观结构进行表征，使用划痕浸泡试验对比探究了PANI/EP复合涂层与PANI/G/EP复合涂层在产生微小缺陷时对不锈钢的保护效果。最后，根据实验结果对PANI/G/EP复合涂层的保护机理进行了探讨。结果 对比实验显示，PANI/G复合材料以及PANI/G/EP复合涂层的电导率均为最高(分别为1.66 S/cm和8.93×10^?3 S/cm)，且PANI/G/EP复合涂层试样的附着力最好(约5.23 MPa)，电化学性能最佳。在50 ℃与60 ℃的1 mol/L硫酸溶液中，PANI/G/EP复合涂层的自腐蚀电位相对不锈钢分别提高了580 mV与470 mV，进入了不锈钢的稳定钝化区，且阳极极化曲线的电流密度显著下降。电化学交流阻抗测试表明，涂覆涂层后，试样阻抗显著增大。对PANI/G复合材料中石墨用量的探究表明，当G∶PANI=2∶100时，涂层的防腐蚀性能最佳。划痕浸泡试验表明，浸泡于50 ℃的1 mol/L硫酸溶液中一周后，PANI/G/EP复合涂层试样缺陷处的暴露基体几乎没有发生腐蚀。结论 石墨(G)能有效提高复合涂层的导电性，强化阳极保护效果。在中温硫酸溶液中，PANI/G/EP复合涂层能同时提供物理屏蔽作用以及显著增强的阳极保护作用，对不锈钢具有优秀的腐蚀防护能力。

This paper aimed to prepare a new anti-corrosion composite coating to enhance the corrosion resistance of 316L stainless steel in medium and high temperature sulfuric acid solution. The chemical oxidation method was used to in-situ-polymerize polyaniline (PANI) on the surface of graphite(G) particles to prepare PANI/G composite material, and then epoxy resin (EP) was added as a film forming agent to prepare PANI/G/EP composite coating. The electrochemical performance, adhesion and conductivity of PANI/G/EP composite coating was compared with that of PANI/EP composite coating and PANI/GO/EP composite coating prepared by adding graphene oxide (GO). Then, the influence of the ratio of graphite to polyaniline on the electrochemical performance of PANI/G/EP composite coating was explored. The chemical bond and micro structure of PANI/EP composite coating and PANI/G/EP composite coating were characterized by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray energy spectroscopy (EDS). The scratch immersion test was used to compare the protective effect of PANI/EP composite coating and PANI/G/EP composite coating on stainless steel when there are small defects. Finally, the protection mechanism of PANI/G/EP composite coating on stainless steel was discussed based on the experimental results. Comparative experiments showed that the PANI/G composite material and the PANI/G/EP composite coating both had the highest electrical conductivity (1.66 S/cm and 8.93×10?3 S/cm respectively), and the PANI/G/EP composite coating sample had the best adhesion (about 5.23 MPa), and it showed the best electrochemical performance. In 1 mol/L sulfuric acid solution at 50 ℃ and 60 ℃, the self-corrosion potential of PANI/G/EP composite coating was significantly increased by 580 mV and 470 mV respectively, both reached the stable passivation zone of stainless steel, and the current density of the anode polarization curve dropped significantly. The electrochemical AC impedance test showed that the impedance modulus of the sample increases significantly after the coating is applied. The investigation of the graphite ratio in PANI/G composite material showed that the coating has the best anti-corrosion performance when G∶PANI= 2∶100. The scratch immersion test showed that after being immersed in 1 mol/L sulfuric acid solution at 50 ℃ for one week, the exposed substrate at the defects of PANI/G/EP composite coating samples hardly corroded. Graphite (G) can effectively improve the conductivity of the composite coating and strengthen the anode protection effect. In the medium temperature sulfuric acid solution, the PANI/G/EP composite coating can provide physical shielding and more significant anodic protection at the same time, and shows a significant corrosion protection effect for stainless steel.