单嘉禄,乌日开西.艾依提,郭钢.石墨烯对激光熔覆镍基复合涂层耐腐蚀性能的影响[J].表面技术,2023,52(5):175-188.
SHAN Jia-lu,AIYITI.Wurikaixi,GUO Gang.Effect of Graphene on Corrosion Resistance of Laser Cladding Nickel Base Composite Coating[J].Surface Technology,2023,52(5):175-188 |
| 石墨烯对激光熔覆镍基复合涂层耐腐蚀性能的影响 |
| Effect of Graphene on Corrosion Resistance of Laser Cladding Nickel Base Composite Coating |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.05.017 |
| 中文关键词: 激光熔覆 石墨烯 Ni60 酸性 中性 碱性 耐腐蚀性能 |
| 英文关键词:laser cladding graphene Ni60 acidic neutral alkaline corrosion resistance |
| 基金项目:新疆维吾尔自治区天山青年计划(2017Q015) |
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| 目的 研究石墨烯(Gr)含量对镍基复合涂层耐腐蚀性能的影响，通过分析Gr对复合涂层耐腐蚀性的影响规律从而确定Gr的最优添加量，同时研究不同Gr含量的镍基复合涂层在3种不同pH值溶液(酸性、中性、碱性)中的腐蚀行为。方法 采用预置粉激光法制备了5种不同Gr含量(质量分数分别为0%、0.3%、0.5%、0.8%、1%)的石墨烯/镍基(Gr/Ni60)复合涂层，并对复合涂层进行腐蚀前表面微观形貌分析、耐腐蚀性能测试、X射线光电子能谱分析、腐蚀后表面形貌分析。结果 在加入Gr的复合涂层中，C元素与Cr元素主要分布在枝晶间，枝晶内区域主要以Fe、Ni为主。随着复合涂层中Gr含量的升高，在酸性腐蚀条件下，自腐蚀电位随着Gr含量的增加而升高，从−0.466 V升高到−0.384 V，极化电阻也由纯Ni60涂层的87.71 Ω/cm2升高到153.53 Ω/cm2，但各涂层均没有明显的钝化区间，主要发生析氢腐蚀，枝晶内腐蚀严重。在中性腐蚀环境下，各涂层出现了明显的钝化区间，当Gr的质量分数为0.8%时，钝化区间最长达到0.285 V，此时相位角值及阻抗模值均达到最大值，且表面生成的氧化物提高了涂层的耐腐蚀性能。在碱性腐蚀条件下，5种不同Gr含量的复合涂层相比于中性腐蚀环境下的复合涂层均出现了较长的钝化区间，当Gr的质量分数为0.8%时，钝化区间长度达到了1.506 V，极化电阻值也达到最大值3 030.32 Ω/cm2，当Gr的质量分数为1%时，3种环境下的耐腐蚀性能较Gr质量分数为0.8%时的耐腐蚀性能均有一定程度的降低。结论 Gr的加入对Ni基复合涂层耐腐蚀性能的积极影响显著。Gr的添加量有最优值，Gr添加过多会使复合涂层耐腐蚀性能降低，碱性腐蚀条件下复合涂层的耐腐蚀性能要优于酸性和中性腐蚀条件下的耐腐蚀性能，当Gr的质量分数为0.8%时，复合涂层具有最优异的耐腐蚀性能。 |
| 英文摘要: |
| Laser cladding (LMD) technology can be used to manufacture 3D components, repair damaged parts and prepare high-performance coatings. It can not only maintain the original advantages of materials, but also enhance other properties of materials, such as wear resistance and corrosion resistance. In recent years, based on various excellent properties, graphene has been used as the reinforcing phase of metal matrix composites, and its properties have been studied. The work aims to study the effect of graphene (Gr) content on corrosion resistance of nickel base composite coating and determine the optimal content of Gr by analyzing the effect of Gr on the corrosion resistance of composite coating, and explore the corrosion behavior of nickel base composite coatings with different Gr contents in three solutions (acidic, neutral and alkaline) with different pH values. Q235 steel was cut into a 160 mm×70 mm×8 mm rectangle and used as the matrix for the experiment, and the rust and oxide scale on the surface were removed by an angle grinder. The surface was polished to be smooth and flat with sandpaper, and the surface of the matrix was wiped clean with absolute ethanol. Different proportions of Gr (0%, 0.3%, 0.5%, 0.8%, and 1%, mass fraction) were added to Ni60 powder as cladding powder. The uniformly mixed Gr/Ni60 powder was put into a 60 mm×40 mm mold and preset on the Q235 matrix, and the preset powder thickness was 0.8 mm. The YLS-2 000 W fiber laser was used in the experiment. The scanning speed in the cladding process was 6 mm/s, the laser power was 1 400 W, and the lap rate between two adjacent channels was 30%. The sample was cut with wire cutting machine, the coating surface was polished to be smooth, and the coating surface was corroded with aqua regia solution (V(HCl)︰V(HNO3)=3︰1), then the micro morphology of the coating surface before corrosion was observed with scanning electron microscope (SUPRA-55VP), and BRUKER X-FLASH- SDD-5010 energy spectrometer (EDS) was adopted to map the coating surface to analyze the element segregation on the coating surface. The corrosion resistance of the coating was analyzed by Linear Sweep Voltammetry (LSV) test and Electrochemical Impedance Spectroscopy (EIS) test with ChenHua CHI660E electrochemical workstation. The surface composition and elemental valence state of the coating were analyzed by semefi K-alpha + X-ray photoelectron spectroscopy tester, and the surface morphology of the coating after corrosion was observed. The Gr/Ni60 composite coating with good bonding with the matrix was successfully prepared on the surface of Q235 by laser cladding technology. The results indicated that the C and Cr elements of the composite coating with Gr were mainly distributed among the dendrites, and the intragranular regions were mainly Fe and Ni. The content of Gr increased with the increase of corrosion potential in the composite coating. Under acidic corrosion conditions, the self-corrosion potential increased with the increase of GR content, from −0.466 V to −0.384 V, and the polarization resistance also increased from 87.71 Ω/cm2 to 153.53 Ω/cm2 of pure Ni60 coating, but each coating had no obvious passivation range, mainly hydrogen evolution corrosion. Under the neutral corrosion environment, each coating had an obvious passivation range when the Gr content was 0.8wt.%, the longest passivation interval reached 0.285 V, the phase angle value and impedance mode value reached the maximum, and oxides were formed on the surface, which improved the corrosion resistance of the coating. Under the condition of alkaline corrosion, the composite coatings with five different Gr contents had a longer passivation range compared with those under the neutral corrosion environment. When the GR content was 0.8wt.%, the passivation interval length reached 1.506 V and the polarization resistance reached the highest value of 3 030.32 Ω/cm2. When the Gr content was 1wt.%, the corrosion resistance of the composite coating was not as good as that of the composite coating with Gr content of 0.8wt.% in the three corrosive environments. The addition of GR has a significant positive effect on the corrosion resistance of Ni base composite coating. The addition amount of GR has the optimal value. Excessive addition of GR will reduce the corrosion resistance of the composite coating. The corrosion resistance of the composite coating under alkaline corrosion conditions is better than that under acidic and alkaline corrosion conditions. When the content of GR is 0.8wt.%, the corrosion resistance of the composite coating is the best. |
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