球形氧化物颗粒的制备及其抗磨减摩性能

发布时间：2018-07-12 09:18

本文选题：氧化物 + 球形颗粒　；参考：《济南大学》2014年硕士论文

【摘要】：纳米摩擦学是随着纳米科学与技术的发展诞生并成为上世纪90年代以来摩擦学基础研究领域最活跃也是材料科学与摩擦学交叉领域最前沿的一个分支学科。这门学科旨在揭示微观摩擦磨损机理，设计并制备纳米尺度上的润滑剂及减摩耐磨材料。从纳米微粒作为润滑油添加剂的摩擦学特性和摩擦学机理分析，具有较高硬度、较好的球形度和良好分散性是颗粒发挥抗磨减摩性能的先决条件，很多氧化物都具有较高的硬度，因此制备球形度较好的纳米颗粒对于其发挥减摩效果至关重要。本论文主要是利用溶剂热法和激光辐照技术制备了几种氧化物颗粒，并研究了他们的抗磨减摩性能。研究内容及结果如下： (1)研究了近球形ZnO纳米颗粒的成球机理和油酸对其表面改性的机理，以及近球形ZnO的抗磨减摩性能。分别采用水热法和溶剂热法制备得到了近球形ZnO纳米颗粒，研究表明油酸钠在颗粒成球的过程中起到了至关重要的作用；选用油酸对溶剂热法制备的颗粒表面改性，提高了其油溶性以及在油中的稳定性，通过正交实验确定了最佳改性方案；摩擦磨损实验表明改性后的ZnO纳米颗粒作为润滑油的添加剂可以有效减小摩擦，但是颗粒的抗磨效果并不明显，当添加浓度为0.1wt%时摩擦系数的降幅为28%，减摩效果达到最大。 (2)利用溶剂热法成功实现了球形三元氧化物ZnAl2O4纳米颗粒的合成以及原位接枝改性，并研究了颗粒的抗磨减摩机理。通过正交实验方法找到了最佳制备与改性实验参数，油酸改性后的ZnAl2O4纳米颗粒可以稳定分散于润滑油中而不沉降；ZnAl2O4纳米颗粒在摩擦磨损实验中最优添加浓度为0.1wt%，摩擦系数和磨斑直径的降幅分别为33.37%和31.15%，表现出了优异的抗磨减摩性能，而且三元氧化物ZnAl2O4颗粒的抗磨减摩效果均优于单一ZnO和Al2O3纳米颗粒作为添加剂时的；由摩擦表面的分析可知纳米颗粒之所以发挥了抗磨减摩效果是由于纳米颗粒的微轴承机理和自修复机理。 (3)利用液相脉冲激光辐照技术处理斜方晶系的α-Fe2O3立方形颗粒后得到了尖晶石结构的球形Fe3O4亚微米颗粒，即在简单的液相激光辐照过程中同时实现了球形化和颗粒的合并以及相转变。实验中可以通过改变激光辐照的能量密度和辐照时间来准确控制颗粒的再成型和相转变过程，提出了在脉冲激光辐照条件下颗粒形貌演变和晶型转换机理。这种激光辐照的方法与传统的化学法相比操作简单、合成时间短，安全、无需催化剂，而且不需复杂苛刻的实验条件。摩擦磨损实验表明当球形Fe3O4亚微米颗粒以合适的浓度（0.07wt%）添加到润滑油中时，，与方形的α-Fe2O3颗粒相比可以更加有效地降低摩擦系数（摩擦系数降幅为40%）以及减小磨损（磨斑直径降幅达22%），表明亚微米颗粒在润滑油添加剂领域的应用潜力，并且验证了颗粒的球形形态对于摩擦学性能提高的重要性。
[Abstract]:Nano tribology was born with the development of nanoscience and technology, and became the most active branch of the field of basic Tribology in the field of tribology since the 90s of last century. This subject aims to reveal the mechanism of friction and wear, and to prepare and reduce the lubricant on the nanometer scale. Friction and wear resistant material. From the tribological and Tribological Mechanism of nano particles as lubricating oil additives, it has high hardness, better sphericity and good dispersity, and many oxides have high hardness. The effect of antifriction is very important. In this paper, several oxide particles are prepared by means of solvent heat and laser irradiation, and their antiwear and antifriction properties are studied. The contents and results are as follows:
(1) the formation mechanism of the near spherical ZnO nanoparticles and the mechanism of oleic acid on its surface modification, as well as the antiwear and antifriction properties of the near spherical ZnO were studied. The near spherical ZnO nanoparticles were prepared by hydrothermal method and solvothermal method. The results showed that sodium oleate played a vital role in the process of forming the ball. The surface modification of particles prepared by solvothermal method has improved its oil solubility and stability in oil. The optimum modification scheme is determined by orthogonal experiment. The friction and wear experiments show that the modified ZnO nanoparticles can effectively reduce friction as the additives of the lubricating oil, but the effect of the particles is not obvious, when the concentration is added. The friction coefficient decreases to 28% when 0.1wt% is applied, and the friction reduction effect reaches the maximum.
(2) the synthesis of spherical three element oxide ZnAl2O4 nanoparticles and in situ grafting modification were successfully realized by solvent thermal method, and the anti friction and friction reduction mechanism of the particles was studied. The optimum preparation and modification experimental parameters were found by orthogonal experiment. The ZnAl2O4 nanometers after oleic acid modification could be dispersed in the lubricating oil without settling. The optimum addition concentration of ZnAl2O4 nanoparticles in friction and wear tests is 0.1wt%, the decrease of friction coefficient and grinding spot diameter is 33.37% and 31.15% respectively, showing excellent antiwear and antifriction properties, and the antiwear and antifriction effect of three element oxide ZnAl2O4 particles is better than that of single ZnO and Al2O3 nanoparticles as additives. The analysis of the friction surface shows that the wear resistance of nanoparticles is due to the micro bearing mechanism and self-healing mechanism of nanoparticles.
(3) the spherical Fe3O4 submicron particles of the spinel structure are obtained by using the liquid phase pulse laser irradiation technology to treat the cubic particles of the crystal structure of the inclined crystal. That is, the spheroidization, the combination of particles and the phase transition are realized during the simple liquid phase laser irradiation, and the energy density of the laser irradiated can be changed in the experiment. The process of remolding and phase transformation of particles is accurately controlled by irradiation time. The evolution of particle morphology and crystal transformation mechanism under the condition of pulsed laser irradiation are put forward. The method of laser irradiation is simple in operation, short in synthesis time, safe, without catalytic agent and without complex and harsh experimental conditions. The loss test shows that when the spherical Fe3O4 submicron particles are added to the lubricating oil with appropriate concentration (0.07wt%), the friction coefficient can be reduced more effectively than the square alpha -Fe2O3 particles (the friction coefficient is reduced to 40%) and the wear is reduced by 22%. It shows that the submicron particles are applied in the field of lubricating oil additives. It also verified the importance of spherical shape of particles in improving tribological properties.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB383.1;TH117

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