相关实验视频
Updated: Jun 12, 2025

13:21
Graphene Coatings for Biomedical Implants
Published on: March 1, 2013
21.3K
酸盐石墨薄纸的部落学特性
Nikolai S Morozov1, David V Demchenko1, Pavel O Bukovsky2
1Lomonosov Moscow State University, Moscow 119991, Russia.
Nanomaterials (Basel, Switzerland)
|September 27, 2024
概括
这项研究揭示了石墨薄膜 (GF) 颗粒大小显著影响三角学性质,较小的颗粒 (40-80μm) 具有较低的摩擦系数和更高的塑性变形. 密度也会影响摩擦,特别是对于较大的粒子,并影响诸如等机械性质.
科学领域:
- 材料科学 材料科学 材料科学
- 部落学 (tribology) 是一个学科.
- 纳米技术 纳米技术
背景情况:
- 石墨薄膜 (GF) 用于各种应用,需要特定的三角学和机械性能.
- 了解原材料特征 (颗粒大小) 和加工参数 (密度,冷) 的影响对于优化GF性能至关重要.
- 之前的研究已经探讨了GF的特性,但需要进行全面的分析,将粒子大小,密度和不同条件下的tribological行为联系起来.
研究的目的:
- 为了研究由不同颗粒大小和密度的天然石墨制成的石墨薄膜 (GF) 的 Tribological 特性.
- 分析静态和动态摩擦测试对表面粗度,摩擦系数和微观结构变化的影响.
- 与粒子大小和密度相关联机械性质,如模量和应力-应变行为.
主要方法:
- 石墨薄膜使用40-80微米,160-200微米和500微米以上的颗粒大小的纯化天然石墨制备,密度为1.0,1.3和1.6g/cm3.
- 在静态 (0.001 mm/s) 和动态 (0.1 Hz,1 Hz) 条件下,经过冷和摩擦试验,测量了表面粗度.
- 测定了摩擦系数,扬模,应力-应变状态,微细菌和剩余的宏细菌. 结构分析包括对连贯散射区域大小和误导角度的测量.
主要成果:
- 与静态测试相比,动态摩擦测试显著增加了表面粗度.
- 摩擦系数随着滑动速度的提高而下降,由40-80μm颗粒制成的GF显示了最低值 (0.13-0.15).
- 扬模量随密度增加而增加,随粒子大小减少. 在GF中观察到更大的塑性变形和微流积累,其中有较小的粒子.
结论:
- 颗粒大小是一个关键因素,影响了石墨薄膜的tribological性能和机械性能.
- 较小的石墨颗粒 (40-80微米) 会导致较低的摩擦系数和增强的塑料变形,表明更好的耐磨性.
- 密度在修改摩擦和机械性能方面发挥着作用,特别是对于较大的粒子分数,累积的变形与摩擦行为相关.
相关概念视频
Characteristics of Dry Friction
516
Dry friction occurs when two solid surfaces slide against each other without any lubrication or fluid present. It causes resistance when pushing objects along a surface, like a gardener pushing a wheelbarrow. The force applied to move the cart causes dry friction between the wheel and the ground.
Before the wheelbarrow starts moving, the static frictional force acts tangentially to the contact surface, opposing the force that is about to induce the motion. This frictional force prevents the...
Before the wheelbarrow starts moving, the static frictional force acts tangentially to the contact surface, opposing the force that is about to induce the motion. This frictional force prevents the...
516
Mechanical Characteristics of Steel
407
The mechanical characteristics of steel are assessed through various tests that evaluate its strength, toughness, and flexibility. These tests include tension, torsion, impact, bending, and hardness assessments, each providing crucial information about steel's suitability for specific applications.
The tension test is fundamental for determining tensile strength. In this test, a steel specimen is stretched using a gripping device until it breaks. The data collected during this test are used...
The tension test is fundamental for determining tensile strength. In this test, a steel specimen is stretched using a gripping device until it breaks. The data collected during this test are used...
407
Network Covalent Solids
13.4K
Network covalent solids contain a three-dimensional network of covalently bonded atoms as found in the crystal structures of nonmetals like diamond, graphite, silicon, and some covalent compounds, such as silicon dioxide (sand) and silicon carbide (carborundum, the abrasive on sandpaper). Many minerals have networks of covalent bonds.
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
13.4K
Design Example: Deciding Thickness of Lubricating Fluid in a Shaft
96
Effective lubrication between a rotating shaft and its bearing housing is essential in rotating machinery to minimize friction, wear, and energy loss. With carefully controlled thickness and viscosity, the lubricant layer prevents metal-to-metal contact, ensuring smooth operation.
To calculate the required thickness of the lubricant layer, the tangential velocity at the shaft's surface must first be determined. This velocity is calculated by converting the rotational speed to angular...
To calculate the required thickness of the lubricant layer, the tangential velocity at the shaft's surface must first be determined. This velocity is calculated by converting the rotational speed to angular...
96
Stress Concentrations in Circular Shafts
166
Consider the elastic torsion formula, which applies to a circular shaft with a consistent cross-section. This formula assumes that the shaft's ends are loaded with rigid plates firmly attached. However, in many cases, torques are applied to the shaft through mechanisms like flange couplings or gears, which are connected by keys inserted into keyways. This application method modifies the stress distribution near the point of torque application, causing it to deviate from the distributions...
166

