摘要
目的研究单次滑动摩擦条件下石蜡/石墨烯复合涂层对单质炸药晶体HMX(110)界面摩擦特性及摩擦安全性的抑制机理。方法采用旋涂法在HMX表面制备石蜡涂层和石蜡/石墨烯复合涂层。通过多功能摩擦磨损试验机和高速红外测温系统测试了HMX表面的摩擦系数和表面最大温度,并通过光学显微镜和拉曼光谱仪分析了HMX磨痕形貌及磨损区域和磨削的化学结构。结果随着接触压力从30.9 MPa增加到51.7 MPa,石蜡涂层使HMX表面摩擦系数和摩擦温升的降幅分别可达63%和61%。然而,向石蜡中引入石墨烯后,石蜡/石墨烯复合涂层使HMX表面摩擦系数和摩擦温升的降幅分别进一步降低至71%和83%。进一步分析表明,随着界面摩擦功率密度的增加,无涂层HMX表面的摩擦功-热转化系数为38%,石蜡涂层使HMX界面的摩擦功-热转化系数降至31%,而向石蜡涂层引入石墨烯后,HMX界面摩擦功-热转化系数进一步降低至24%。此外,石蜡涂层可使HXM摩擦感度从72%降低至16%,而石蜡/石墨烯复合涂层可进一步将HMX摩擦感度降至10%。结论石蜡/石墨烯复合涂层在降低摩擦系数与降低摩擦功-热转化系数的双重机制主导下,通过减少直接接触、分散能量积累并加速热量耗散,显著抑制HMX界面摩擦热失控行为,为高能炸药的安全应用提供了理论依据。
As a representative energetic material,cyclotetramethylene tetranitramine(HMX,C4H8N8O8)has become a crucial energy carrier in modern high-energy weapon systems due to its high energy density and detonation velocity,currently finding extensive applications in defense fields such as polymer-bonded explosives(PBXs)and solid rocket propellants.However,the heat accumulation caused by interfacial friction during processing and transportation may trigger accidental ignition,posing a critical safety challenge.Current research primarily focuses on the macroscopic characterization of frictional temperature rise in PBXs,while significant knowledge gaps remain regarding to the microscopic mechanisms and active control methods for interfacial friction-induced temperature rise in HMX single compound explosives.Although surface coating technologies can remarkably improve the HMX's frictional safety,limitations such as lubricant performance degradation under extreme loads and insufficient thermal conduction efficiency still restrict the effectiveness of single-layer coatings.Furthermore,how will the composite coating that synergistically combines lubrication and thermal management affect the interfacial friction behavior of explosives remains unclear,this severely hinders the development of active frictional safety control technologies for explosives.Therefore,this study aims to investigate the inhibition mechanism of the wax/graphene composite coating on the frictional properties of HMX(110)crystal surfaces,with the goal of enhancing the frictional safety of HMX during mechanical processing and transportation and providing theoretical insights for improving the safety of energetic materials.To systematically elucidated the mechanism by which the wax/graphene composite coating suppresses the frictional characteristics of HMX(110)surfaces,interfacial tribological experiments on HMX explosive crystals were conducted with a reciprocating tribometer(MFT3000),and the counter-surface for the tribology was a HMX tip.To amplify the interfacial friction coefficient and temperature rise characteristics of HMX crystals,the experimental parameters were systematically configured with a contact pressure range of 30-60 MPa,sliding velocity of 50 mm/s,and friction distance of 15 mm.To ensure data reliability and reproducibility,each test was conducted in quintuplicate under identical tribological conditions.After the tribological experiment,post-test morphological characterization of HMX wear tracks was performed with an optical microscope(BX51-P),while chemical structural analysis of wear-induced scratches and debris was conducted via Raman spectroscopy.Real-time temperature monitoring at the HMX friction interface was achieved through a high-speed infrared thermography system,featuring a spatial resolution of 120μm and temporal resolution of 5 ms,with thermal emissivity calibrated to 35%and measurement accuracy maintained within±5%.For evaluating the frictional safety of coated HMX specimens,sensitivity testing was executed following the standard protocol GJB 5891.24-2006 with a BM-B pendulum friction apparatus.Specifically,20 mg samples were compressed between hardened steel anvils and subject to 50 consecutive impacts at a 66°contact angle under 1.5 MPa pressure.The results demonstrated that as the contact pressure increased from 30.9 MPa to 51.7 MPa,the wax/graphene composite coating reduced the surface friction coefficient of HMX by up to 71%and effectively suppressed interfacial frictional temperature rise by 83%.Notably,the composite coating showed superior performance to the wax coating,achieving additional reduction of 34%in friction coefficient and 33%in temperature rise.Further analyses revealed that the composite coating significantly inhibited the frictional work-heat conversion coefficient on HMX surfaces.The frictional work-heat conversion coefficient for uncoated HMX surfaces was 38%,it reduced to 31%with the application of the wax coating,and it further reduced to 24%with the application of the wax/graphene composite coating.This represents maximum reductions of approximately 36.8%and 22.6%compared with uncoated and wax-coated HMX,respectively.Additionally,the wax coating reduced the frictional sensitivity of HMX from 72%to 16%,while the wax/graphene composite coating achieved a further reduction of frictional sensitivity to 10%,demonstrating a 37.5%additional improvement over the wax coating.The observed results in the present study conclude that the wax/graphene composite coating,governed by dual mechanisms of reducing friction coefficient and frictional work-heat conversion coefficient,can effectively mitigate frictional thermal runaway at HMX interfaces by minimizing direct contact,dispersing energy accumulation,and accelerating heat dissipation.These findings can provide a theoretical foundation for the safety assessment of high-energy explosive materials.
作者
朱晓
何洪途
李国成
王敬凯
余家欣
银颖
ZHU Xiao;HE Hongtu;LI Guocheng;WANG Jingkai;YU Jiaxin;YIN Ying(Key Laboratory of Testing Technology for Manufacturing Process,Southwest University of Science and Technology,Sichuan Mianyang 621010,China;Institute of Chemical Materials,China Academy of Engineering Physics,Sichuan Mianyang 621999,China)
出处
《表面技术》
北大核心
2025年第23期127-140,共14页
Surface Technology
基金
国家自然科学基金(52575239)
高端装备界面科学与技术全国重点实验室开放基金项目(SKLTKF22A01)
四川省科技厅资助项目(2024NSFSC0147,2024NSFTD0019)。
关键词
HMX
石蜡/石墨烯复合涂层
摩擦特性
摩擦功-热转化系数
摩擦感度
HMX
wax/graphene composite coating
frictional properties
frictional work-heat conversion coefficient
frictional sensitivity
