郎梼,刘刚,何伟焕,李勇,刘加将.高粗糙度NiCrB打底层对陶瓷颗粒增强聚合物基复合涂层性能的影响[J].表面技术,2024,53(5):205-213.
LANG Tao,LIU Gang,HE Weihuan,LI Yong,LIU Jiajiang.Effect of High Roughness NiCrB Bond Coat on Properties of Ceramic Particle Reinforced Polymer Composite Coating[J].Surface Technology,2024,53(5):205-213 |
| 高粗糙度NiCrB打底层对陶瓷颗粒增强聚合物基复合涂层性能的影响 |
| Effect of High Roughness NiCrB Bond Coat on Properties of Ceramic Particle Reinforced Polymer Composite Coating |
| 投稿时间：2023-05-25 修订日期：2023-10-31 |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.05.021 |
| 中文关键词: 镍基打底层 电弧喷涂 高粗糙度 高结合强度 耐腐蚀性能 |
| 英文关键词:nickel-based bond coat arc spraying high roughness high adhesion corrosion resistance |
| 基金项目:华能集团总部科技项目(HNKJ21-HF243) |
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| Author | Institution |
| LANG Tao | Sichuan Huaneng Kangding Hydropower Co., Ltd., Chengdu 610041, China |
| LIU Gang | Xi'an Thermal Power Research Institute Co., Ltd., Xi'an 710054, China |
| HE Weihuan | Sichuan Huaneng Kangding Hydropower Co., Ltd., Chengdu 610041, China |
| LI Yong | Xi'an Thermal Power Research Institute Co., Ltd., Xi'an 710054, China |
| LIU Jiajiang | Sichuan Huaneng Kangding Hydropower Co., Ltd., Chengdu 610041, China |
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| 中文摘要: |
| 目的 提高水电装备过流部件表面聚合物基复合抗空蚀涂层与碳钢基材的结合强度，解决因聚合物涂层局部分层，使得水进入聚合物涂层与碳钢界面，引起碳钢快速氧化膨胀，导致涂层快速剥落的难题。方法 采用电弧喷涂技术在碳钢基材表面制备NiCrB高粗糙度耐腐蚀打底层，然后在其上涂覆聚氨酯基复合涂层。通过激光共聚焦显微镜、扫描电镜，以及结合强度测试、电化学测试和中性盐雾测试，分别表征打底层的表面形貌、致密度，并评价打底层对聚氨酯基复合结合强度和防腐蚀性能的影响。结果 通过调控参数，在NiCrB打底层表面形成由熔滴气化后沉积形成的规则排布凸起颗粒，涂层的表面粗糙度相较于常规热喷涂涂层得到显著提高，在Ra 10.95~37.24 μm内可有效调控，且涂层的孔隙率均低于1.5%。添加高粗糙度致密NiCrB打底层后，聚氨酯基复合涂层的结合强度由13.6 MPa升至30.5 MPa。在基体添加NiCrB打底层后，其开路电位由−0.73 V升至−0.54 V，腐蚀电位(vs. SCE)由−0.76 V升至−0.58 V，电荷转移电阻由1 729 Ω.cm2升至8 425 Ω.cm2。在上层聚合物涂层破损的情况下，带有NiCrB打底层的样品在接受300 h中性盐雾测试后无明显锈点，相较于无打底层样品，其盐雾腐蚀寿命提高了11倍以上。结论 通过电弧喷涂NiCrB打底层可以在较大范围内实现表面粗糙度的调控，打底层的高粗糙度显著提升了聚合物基复合涂层的结合强度，打底层优异的耐腐蚀性能显著提升了聚合物基复合涂层的长效耐腐蚀性能，保障了水力过流部件的长效服役。 |
| 英文摘要: |
| The hydraulic flow components, such as turbines and volutes, in high-sediment rivers are susceptible to surface wear, cavitation erosion, and corrosion due to the presence of high-sediment water flows. These issues can lead to rapid failure of these components, thereby affecting the safety and stable operation of the power plant. Polymer-based composite coatings offer several advantages over other methods, including low cost, excellent cavitation resistance, and high construction flexibility, which have been widely employed for surface protection of carbon steel parts. However, polymer-based composite anti-cavitation coatings often exhibit poor bonding with the carbon steel substrate, and localized coating damage can lead to rapid oxidation and rusting of the carbon steel, resulting in peeling of the coating. To address these problems, in the present paper, it is proposed to greatly enhance the bonding strength and increase the corrosion resistance of the polymer-based composite coating by introducing a NiCrB bond coat with high surface roughness. The NiCrB bond coat was prepared on the carbon steel surface by using arc spraying technology, which offered high flexibility and low cost. During this process, the nickel-based wire was melted and partially evaporated due to the high arc temperature of up to 6 000 ℃. The liquid-gas two-phase deposition ensured a high surface roughness, thereby strengthening the mechanical locking between the polymer-based composite coating and the low carbon steel substrate. Consequently, the bonding strength and service life of the coating could be improved. Subsequently, a ceramic-reinforced polymer coating was coated onto the NiCrB bond coat. The surface morphology and roughness of the bond coat were measured with a laser confocal microscope. The bonding strength of the coating was tested with an Instron 1195 tester according to the ASTM C633 standard. The corrosion resistance of the coating was evaluated through measurements of open circuit potential, impedance spectrum, polarization curve, and neutral saltfog spray corrosion. The results indicated that, through parameter control, regularly arranged convex particles could be formed on the surface of the NiCrB coating after droplet gasification. The surface roughness of the coating was significantly higher than that of conventional thermal spraying coatings, ranging from Ra 10.95-37.24 μm, while the porosity remained below 1.5%. The addition of a high-roughness dense NiCrB layer increased the bonding strength of the polyurethane-based composite coating from 13.6 MPa to 30.5 MPa. Moreover, the incorporation of NiCrB in the substrate elevated the open circuit potential from −0.73 V to −0.54 V, the corrosion potential from −0.76 V vs. SCE to −0.58 V vs. SCE, and the charge transfer resistance from 1 729 Ω.cm2 to 8 425 Ω.cm2. It was found that even the top polymer-based coating was cracked, the sample with a NiCrB bond coat exhibited no visible rust spots after a 300 h neutral salt fog spray test, representing an 11-fold increase compared with the sample without the bond coat. In summary, arc-sprayed NiCrB coating allows for effective control of surface roughness within a wide range. The enhanced roughness significantly improves the bonding strength of the polymer-based composite coating. The superior corrosion resistance of the coating ensures long-term protection and the extended service life of hydraulic flow components. |
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