Oil-impregnated porous polyimide(iPPI)materials are usually used as retainer for bearings.In these bearings,balls and rings,balls and retainers are two different kinds of contact.In this paper,the friction and wear pr...Oil-impregnated porous polyimide(iPPI)materials are usually used as retainer for bearings.In these bearings,balls and rings,balls and retainers are two different kinds of contact.In this paper,the friction and wear properties of iPPI were investigated using steel(disc)–steel(ball)–iPPI(pin)double-contact friction test rig for simulating the actual contact in bearings.The results show that compared with that of iPPI–steel single contact,the friction coefficient of iPPI–steel in double contacts is lower and decreases with the amount of additional oil.The surface of iPPI in single contact suffers more wear compared with that in double contacts.Different from single contact,the worn surfaces of iPPI in double contacts are blackened.The Raman spectra of worn surfaces of balls and discs indicate thatα-Fe_(2)O_(3) and Fe_(3)O_(4) were formed during rubbing of the double contacts.Many nanoscale iron oxide particles are found on the worn surfaces of iPPI in double contacts;on the contrary,few particles could be found on the surface in single contact.In double-contact friction,the nanoscale wear debris penetrates inside the iPPI material through the process of extruding and recycling of oil,which is the mechanism of the blackening of the iPPI worn surfaces.The studies show that the double-contact friction method is a new and effective method to study the friction in bearings,especially for those with polymer retainer.展开更多
【目的】研究硅藻土对硅酸钠的吸附效果,探讨油井水泥环微裂缝的修复问题。【方法】采用硅酸钠作为自愈合剂,硅藻土为载体,利用真空浸渍法制备硅藻土基自愈合材料;借助扫描电子显微镜(scanning electron microscope,SEM)、红外光谱仪(in...【目的】研究硅藻土对硅酸钠的吸附效果,探讨油井水泥环微裂缝的修复问题。【方法】采用硅酸钠作为自愈合剂,硅藻土为载体,利用真空浸渍法制备硅藻土基自愈合材料;借助扫描电子显微镜(scanning electron microscope,SEM)、红外光谱仪(infrared spectrometer,FTIR)、全自动表面积和孔结构分析仪(automatic surface area and pore structure analyzer,BET)进行分析;通过对比分析掺入硅藻土基自愈合材料前、后水泥石的抗压强度、恢复率和渗透率等,对自愈合效果进行评价;通过对水泥石裂缝表面物质进行X射线衍射分析(X-ray diffraction,XRD)、热重分析(thermal analysis,TG)和SEM分析评价材料的自愈合机制。【结果】利用真空浸渍法能够成功制得硅藻土基自愈合材料;硅藻土基自愈合材料在油井水泥中最佳掺量为9%(质量分数),该试样劈裂造缝后自愈合14 d的抗压强度比纯水泥的提高99.57%,自愈合14 d后渗透率为0.42 mD,渗透率降低率达到75.44%,比纯水泥试样的高40.94%,且自愈合14 d后裂缝表面已经闭合。【结论】硅藻土基自愈合材料制备工艺简单,在油井水泥浆中具有良好的分散性和稳定性,可以促进油井水泥石微裂缝自愈合。展开更多
油藏是典型的高温、高压、高矿化度且厌氧的多重极端环境,油藏微生物是其中重要的组成部分。研究油藏微生物对阐明油气资源的形成、生物地球化学循环及生命起源与进化等过程有重要意义。通过文献调研,对油藏中微生物的相互作用方式、机...油藏是典型的高温、高压、高矿化度且厌氧的多重极端环境,油藏微生物是其中重要的组成部分。研究油藏微生物对阐明油气资源的形成、生物地球化学循环及生命起源与进化等过程有重要意义。通过文献调研,对油藏中微生物的相互作用方式、机理和主要功能进行了阐述,对油藏微生物在提高石油采收率、石油污染生物修复以及碳捕集、利用与封存(carbon capture,utilization and storage,CCUS)等领域中的作用机理和应用进展进行了总结,并提出了未来在利用油藏微生物过程中还需要解决的关键问题。油藏微生物在油气勘探及环境修复应用中具有经济成本较低和环境友好的优势,未来具有良好的应用前景。研究成果可为油藏微生物的研究和应用提供参考。展开更多
基金This work was supported by the Natural Science Foundation of Zhejiang Province(No.LY21E050003)Science and Technology Innovation 2025 Major Project of Ningbo(No.2019B10078).
文摘Oil-impregnated porous polyimide(iPPI)materials are usually used as retainer for bearings.In these bearings,balls and rings,balls and retainers are two different kinds of contact.In this paper,the friction and wear properties of iPPI were investigated using steel(disc)–steel(ball)–iPPI(pin)double-contact friction test rig for simulating the actual contact in bearings.The results show that compared with that of iPPI–steel single contact,the friction coefficient of iPPI–steel in double contacts is lower and decreases with the amount of additional oil.The surface of iPPI in single contact suffers more wear compared with that in double contacts.Different from single contact,the worn surfaces of iPPI in double contacts are blackened.The Raman spectra of worn surfaces of balls and discs indicate thatα-Fe_(2)O_(3) and Fe_(3)O_(4) were formed during rubbing of the double contacts.Many nanoscale iron oxide particles are found on the worn surfaces of iPPI in double contacts;on the contrary,few particles could be found on the surface in single contact.In double-contact friction,the nanoscale wear debris penetrates inside the iPPI material through the process of extruding and recycling of oil,which is the mechanism of the blackening of the iPPI worn surfaces.The studies show that the double-contact friction method is a new and effective method to study the friction in bearings,especially for those with polymer retainer.
文摘油藏是典型的高温、高压、高矿化度且厌氧的多重极端环境,油藏微生物是其中重要的组成部分。研究油藏微生物对阐明油气资源的形成、生物地球化学循环及生命起源与进化等过程有重要意义。通过文献调研,对油藏中微生物的相互作用方式、机理和主要功能进行了阐述,对油藏微生物在提高石油采收率、石油污染生物修复以及碳捕集、利用与封存(carbon capture,utilization and storage,CCUS)等领域中的作用机理和应用进展进行了总结,并提出了未来在利用油藏微生物过程中还需要解决的关键问题。油藏微生物在油气勘探及环境修复应用中具有经济成本较低和环境友好的优势,未来具有良好的应用前景。研究成果可为油藏微生物的研究和应用提供参考。
