复合改性二氧化硅纳米润滑演化机理及冷轧流变特性研究

The application of lubrication technology in strip cold rolling is one of the effective approaches to save energy, reduce exhaust emissions and improve the quality of products. The lubrication films of traditional oil-in-water lubricants are easily broken under the cold rolling process, resulting in the failure of rolls and surface defects on the products. Nano lubricants have the dual advantages in cooling and extreme pressure properties, particularly in high temperature and pressure. This project is targeted to the ineffectiveness of traditional lubricants in cold rolling, investigate the mechanism of lubrication evolution for bifunctional modification silica nanoparticles in lubrication and the optimization of the bifunctional proportion, and analyze the rheological properties of nano lubricants under cold rolling. Firstly, different silane coupling agents will be used to modify the silica nanoparticles, disclosing the effect of different functional groups on the dispersity in the base oil and adsorption on the rubbing surface. Secondly, both the dispersity and adsorption are considered to modify with bifunctional groups. The mechanism of lubrication evolution for bifunctional modification silica nanoparticles with different proportions will be analyzed to optimize the modification proportion. Finally, the discrete phase model of the nano lubricants in the entry zone of cold rolling will be established to analyze the rheological properties of different nano lubricants, optimizing the particle size and solutions under given practical rolling circumstances. The implementation of this project will be significant in facilitating the theory of nano lubrication in rolling process.

带材冷轧过程中工艺润滑技术是节能减排和提高轧件质量有效措施之一，传统水包油乳化液在冷轧条件下油膜极易发生破裂，造成轧辊失效和轧件表面质量缺陷。纳米润滑油具有优良的冷却性能和极压性能，在高温、高压条件下效果尤为显著。本项目针对冷轧过程传统润滑油润滑效果不佳，研究复合改性二氧化硅纳米颗粒润滑演化机制、优化复合改性比例，并分析其轧制工况流变特性。首先，采用不同硅烷偶联剂对一定粒径二氧化硅纳米颗粒进行改性，揭示不同官能团对纳米颗粒在基础润滑液中分散性和摩擦副表面吸附性影响规律；其次，综合考虑纳米颗粒的分散性和吸附性对其进行复合改性，分析不同复合改性官能团比例纳米颗粒润滑演化机理，优化设计复合改性比例；最后，建立轧制工况变形区入口纳米流体流变离散相模型，分析不同纳米流体流变规律，优化实际轧制应用二氧化硅纳米颗粒粒径及浓度。项目实施对促进轧制工艺纳米润滑理论发展具有十分重要意义。

本项目首先开展三种纳米颗粒作为油基润滑液添加剂研究，制备不同浓度纳米润滑液，通过球-盘摩擦磨损研究三种纳米颗粒的减摩抗磨属性；其次，采用轧制过程中常用到的无限冷硬辊和高速钢为研究对象，将其在650℃和700℃下在水蒸气和干燥空气中恒温氧化，分析恒温氧化过程热重曲线、X射线衍射、扫描电镜等手段表征氧化物，对比揭示无限冷硬辊和高速钢氧化行为。再其次，采用Stöber法制备粒径为60nm SiO2纳米颗粒，根据纳米离子材料的方法对其进行亲两性改性，分别将SIT8378.3和Ethomeen HT/60链接到SiO2纳米颗粒表面，得到亲两性室温无溶剂情况液体纳米粒子材料，通过球-盘摩擦磨损实验研究其作为水基和油基添加剂减摩抗磨机理。最后，制备粒径为100 nm的二氧化硅纳米颗粒，并将其沉积在氧化石墨烯表面，通过纳米离子的方法对其进行改性，在其内冠层链接SIT8378.3，外冠层链接Jeffamine M-2070，得到室温无溶剂条件下液态SiO2@GO复合粒子，通过TEM、TGA等手段表征，将其作为水基润滑液添加剂，通过球-盘摩擦磨损实验研究其作为水基纳米添加剂减摩抗磨机理。