高碱性润滑油中硼酸钙添加剂的摩擦学性能

发布时间：2018-04-09 08:52

本文选题：等离子辅助球磨　切入点：高碱性润滑油　出处：《集美大学》2017年硕士论文

【摘要】：本文选用油酸、十六烷基三甲基溴化铵(CTAB)分别作为修饰剂,利用等离子辅助球磨技术制备了表面修饰硼酸钙添加剂。通过扫描电子显微镜、X射线衍射仪、傅里叶红外光谱仪、同步热分析仪等方法对其进行形貌观察及结构表征,并探究其在高碱性润滑油中的分散性和摩擦学性能。对所制备的硼酸钙添加剂进行扫描电镜观察发现,油酸修饰后的硼酸钙粒径在50nm—300nm之间,而CTAB修饰的硼酸钙一次颗粒平均粒径只有50nm左右,球磨后的粉体聚集成大约500nm左右的团聚体。X射线衍射分析表明,等离子辅助球磨快速细化了硼酸钙的晶粒尺寸,但没有使硼酸钙的晶型结构发生改变。红外光谱及同步热分析表明,等离子辅助球磨促使油酸和CTAB发生断键,产生亚甲基-CH2活性基团与原始硼酸钙粉体表面发生聚合。重力沉降实验发现,原始硼酸钙添加到高碱性润滑油后,3天后出现明显的沉淀分层现象;油酸修饰硼酸钙及CTAB修饰硼酸钙在高碱性润滑油中经历后100天仍基本保持稳定,未出现明显分层现象。这表明油酸及CTAB对硼酸钙形成了良好的表面修饰,使粉体表面改性为亲油性。理化性能测试结果表明,在保持高碱性润滑油粘度、闪点及倾点基本不变的情况下,油酸修饰硼酸钙复合油碱值提升31.16%,CTAB修饰硼酸钙复合油碱值提升33.43%。这对于减少金属清净剂的使用,降低金属灰分具有重要意义。对两种表面修饰硼酸钙添加剂复配的高碱性润滑油进行摩擦学性能测试,结果表明随着载荷增大,纳米硼酸钙复合油的摩擦系数逐渐减低,并且在试验过程中摩擦系数保持平稳,磨损体积也随着载荷增加呈现下降趋势。对摩擦副表面进行电子能谱测试,发现摩擦副表面含有B、Ca、O等元素,这说明纳米硼酸钙添加剂在摩擦力的剪切作用下铺展成膜,覆盖到摩擦副表面,对摩擦副表面起到减摩修复作用。相对于油酸修饰硼酸钙,CTAB修饰硼酸钙的减摩抗磨效果更佳,这是因为CTAB修饰硼酸钙的粒径更小,随着载荷增大,在摩擦力的剪切作用下,硼酸钙易于分散展开,使得CTAB修饰硼酸钙在摩擦副表面铺展更易于成膜。对所调配的复合油用硫酸进行酸化处理,模拟在船用柴油机酸性工况下,测试硼酸钙添加剂的减摩抗磨性能,结果发现:纳米硼酸钙添加剂同样具有良好的减摩抗磨能力,但由于硫酸与清净剂胶团中的碳酸钙及纳米硼酸钙添加剂发生化学反应生成硫酸钙,混杂在硼酸钙沉积膜表面,影响摩擦副表面覆盖膜强度,硼酸钙保护膜容易开裂剥落。
[Abstract]:This selection of oleic acid, sixteen alkyl three methyl bromide (CTAB) were used as modification agent, surface modification of calcium borate additives were fabricated by plasma assisted ball milling. By scanning electron microscopy, X ray diffraction, Fourier transform infrared spectroscopy, thermal analyzer and other methods to characterize the morphology and structure, and explore the in the high alkaline lubricating oil in the dispersion and tribological properties. SEM observation showed that the preparation of calcium borate additive, oleic acid modified calcium borate with a particle size of 50nm - 300nm, and CTAB modified calcium borate once the average particle size is about 50nm, the powder milled polymer aggregates.X - ray diffraction integration about 500nm analysis shows that the plasma assisted ball milling and rapid refinement of the grain sizes of calcium borate, but did not make the crystal structure of calcium borate IR and change. Simultaneous thermal analysis showed that the plasma assisted ball milling leads to the bond breaking of oleic acid and CTAB, -CH2 methylene produced active group and original calcium borate powder surface polymerization. The sedimentation experiment indicated that, the original calcium borate added to high alkaline lubricating oil, after 3 days of precipitation obviously stratified; oleic acid modified calcium borate and CTAB modification experience in high calcium borate alkaline lubricating oil after 100 days still remained stable, there is no obvious stratification. It showed that oleic acid and CTAB formed on the surface modification of calcium borate good, the surface modification of powder is hydrophobic. The physicochemical properties test results show that, while maintaining a high level of alkaline lubricating oil viscosity, flash point and pour point unchanged, oleic acid modified calcium borate composite oil alkali value increased by 31.16%, CTAB modified calcium borate composite oil alkali 33.43%. to enhance the value of this is to reduce the use of metal detergent, lower metal ash More important. Tribology performance test of two kinds of high alkaline lubricating oil surface modified calcium borate additives. The results show that as the load increases, the friction coefficient of Calcium Borate Nanoparticles Composite oil decreased gradually, and the friction coefficient remained stable during the test, the wear volume is decreased with the increase of load on the friction. The surface of the electronic energy spectrum test, found to contain B, friction surface Ca, O and other elements, it indicated that nano calcium borate additive film in friction shearing spreading, to cover the surface of the friction pair surface of friction pair, friction reducing and repairing effect. Compared with oleic acid modified calcium borate, CTAB modified calcium borate by better anti-wear effect, this is because the CTAB modified calcium borate has smaller particle size, as the load increases, the shear friction, easy to disperse calcium borate, the CTAB modified Calcium borate in the friction surface spreading more easily into film. On the side of composite oil the deployment of acidification with sulfuric acid, the simulation of marine diesel engine under acidic conditions, the friction and wear performance, reducing test results showed that calcium borate additive calcium borate nanoparticles additive has good anti friction and anti-wear ability, but because with sulfuric acid detergent micelles of calcium carbonate and Calcium Borate Nanoparticles additives react to produce calcium sulfate, calcium borate mixed on the surface of the deposited film, the effect of friction pair surface coating strength, easy cracking and spalling of calcium borate protective film.

【学位授予单位】：集美大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE624.82

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