Page 14 - 摩擦学学报2025年第5期
P. 14
648 摩擦学学报(中英文) 第 45 卷
2. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics,
Chinese Academy of Sciences, Gansu Lanzhou 730000, China;
3. School of Mechanical Engineering, Xinjiang University, Xinjiang Urumqi 830017, China)
Abstract: A series of Si and N co-incorporated DLC (Si/N-DLC) coatings were deposited using plasma enhance
chemical vapor deposition (PECVD) technology under varying SiH 4 /N 2 flow ratios, and the dependence of the coatings’
microstructure, mechanical properties and tribological behavior in oilfield produced water environment on the SiH 4 /N 2
flow ratio was investigated, focusing on the lubrication and failure mechanisms in the oilfield environment. The results
demonstrated that the Si/N-DLC coatings exhibited high-quality surface and cross-sectional morphologies, with smooth
surfaces (R a : 0.97~2.00 nm) and no micro-defects or cracks. As the SiH 4 /N 2 flow ratio decreased, the Si content in the
coating gradually decreased (from 6.98% to 0.00%), while the N content gradually increased (from 0.00% to 6.37%).
3 2
This compositional change induced a structural transformation of the coating from sp to sp bonding. Consequently, the
hardness and elastic modulus decreased overall, whereas the toughness and adhesion strength were significantly
improved, attributed to the formation of strong covalent bonds between C and N within the coatings. The Si/N-DLC
coatings substantially enhanced the tribological performance of the 316L SS substrate in oil field environments. The
friction coefficient and wear rate exhibited a decreasing-then-increasing trend with decreasing SiH 4 /N 2 flow ratio.
Notably, the Si 60 /N 40 coating system achieved a low friction coefficient of 0.024 and an ultra-low wear rate of 1.80×
–8 3
10 mm /N·m). The lubrication mechanism was attributed to the formation of a solid-liquid composite lubrication
system with the oil field produced water. In the mixed lubrication state, the synergistic effect of the liquid film on the
coating surface and the graphitized transfer film on the wear scar surface not only shifted the frictional shear interface,
but also effectively hindered material transfer (further wear) at the friction interface. This synergy significantly reduced
the friction coefficient of the coating and enhanced its wear resistance. For Si/N-DLC coatings deposited at higher
(Si 100 /N 0 ) and lower (Si 20 /N 80 and Si 0 /N 100 ) SiH 4 /N 2 flow ratios, the dominant wear mechanisms were abrasive wear and
corrosive wear, respectively, both exhibiting higher wear rates and even failure. These findings provided valuable
insights for advancing the application of DLC coatings in tribological protection under oil field conditions.
Key words: Si/N-DLC coating; SiH 4 /N 2 flow ratio; oilfield environment; ultra-low wear; lubrication mechanism
尽管新能源产业在全球迅速发展,石油作为全球 DLC涂层(Si/N-DLC)在降低残余应力和提升服役性
[1]
主要能源的战略地位仍难以撼动 . 同时,塑料和化纤 能,特别是在耐腐蚀和摩擦学性能方面显示出显著潜
[17]
等化工产品的生产高度依赖于石油衍生物,石油供应的 力 [17-21] . 例如,Wang等 将热力学稳定的Si–N和C–N
稳定性与国家安全密切相关. 但石油资源有限,为提高 键引入DLC涂层,使Si/N-DLC涂层在500 ℃高温下表
现出优异的摩擦学性能;Zhao等 比较了氢化DLC、
[22]
采收率,广泛采用CO 增强采油(CO -EOR)等三次采油
2
2
[2-3] Si掺杂氢化DLC和Si/N-DLC涂层在 NaCl质量分数为
技术. 开采过程中,油田产出的液体含水率超过90% .
3.5%溶液中的耐腐蚀行为,发现Si和N的协同作用显
这些产出水中含有大量悬浮颗粒和溶解的腐蚀性矿物
著提升了DLC涂层的耐腐蚀性能. 作者此前的研究 [23-24]
[4]
+
质(如Cl 、H 和 HCO 等),腐蚀与磨损 的协同作用对
−
−
3
也发现,Si/N-DLC涂层在海洋和油田环境中具有优异
管道和开采设备及其关键部件表面造成不可逆损伤,
的耐腐蚀性,归因于N的增韧作用和Si腐蚀产物的扩
导致重大经济损失和安全风险,因此,亟需开发高性
散. 然而,目前的研究多集中于单一环境下的腐蚀 [21, 23, 24]
能材料和技术. [17, 19, 25]
或摩擦行为 ,针对腐蚀与磨损协同作用下的性
表面涂层技术通过在金属表面沉积防护层,有效 能,特别是油田环境中的摩擦学行为和润滑机制相关
抵御腐蚀环境侵蚀并增强耐磨性能,可替代昂贵的高 研究仍然匮乏,这对于开发适用于油田环境的高性能
性能防腐耐磨合金,是1种经济高效的解决方案. 类金 DLC防护涂层具有重要意义.
刚石碳(Diamond-like carbon, DLC)涂层因其优异的功 因此,本研究中采用等离子体增强化学气相沉积
能特性,如高硬度、低摩擦系数、耐磨性和耐腐蚀性 [5-8] , 技术(PECVD),在不同SiH /N 流量比条件下沉积了
4
2
受到广泛关注. 掺杂是突破DLC涂层固有性能极限的 Si/N-DLC涂层,系统地研究了其微观结构、形貌、力
有效措施 [9-11] ,尤其是非金属掺杂DLC涂层 [12-14] 可避免 学性能和油田环境下的摩擦学行为,重点揭示其在油
金属元素与碳基体间电位差引起的电偶腐蚀 [15-16] ,展 田环境中的润滑机理,为发展高质量DLC防护涂层和
现出优异的性能和稳定性. 其中,Si和N元素共掺杂的 推动其在油田环境下的摩擦防护提供理论指导.