Guanghu Jin

Bio: Guanghu Jin is an academic researcher from Nanjing University of Aeronautics and Astronautics. The author has contributed to research in topics: Lubrication & Composite number. The author has an hindex of 1, co-authored 3 publications receiving 1 citations.

Water Lubrication of Ni/Al2O3 Composite Coatings Sliding With Si3N4

Abstract: Inspired by the excellent water lubrication properties of Al2O3, two methods are used to fabricate Ni/Al2O3 composite coatings for water lubrication. One is the conventional composite electroplating technique (one-step process). The other is depositing the Al2O3 particles layer on a substrate by electrophoresis firstly and then plating of Ni (two-step process). The morphology of surface and cross section, composition, micro-hardness, and bonding strength of the coatings were investigated. The water lubrication properties of the coatings sliding with Si3N4 were tested and compared. The result shows that the electrophoresis combined with electroplating is an efficient way to improve the Al2O3 particles content in the coatings. With the increasing of the particle content, the coating hardness increases while the bonding strength decreases. More importantly, low friction coefficient can only be achieved for Ni/Al2O3 coating with higher particle content. The comprehensive tribo-chemical reactions of Al2O3 and Si3N4 with water could be the dominated reason. The finds evidence the benefits of the ceramic-based composite coating design for water lubrication.

Ferrofluid lubrication for ball bearings to avoid starvation

Abstract: This paper aims to prevent oil starvation and improve the service life of the rolling bearings.,A thrust ball bearing with magnetic circuit structure is proposed for ferrofluid lubrication. With the aid of magnetic field, ferrofluid can be maintained in the contact area of rolling bodies to delay lubricant loss. Experiments are performed to ensure the validity of the designed bearing.,Compared with conventional lubricant, service life of the ferrofluid lubricated bearing can be prolonged under magnetic field. In addition, with a proper magnetic field distribution, lubricant starvation may be limited under the conditions of present experiments.,This work provides a method to control the starved lubrication of rolling bearings with restricted lubricant supply.,The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0132/

Droplets Impacting and Migrating on Structured Surfaces With Imposed Thermal Gradients

Abstract: In this work, the dynamic process of oil droplets impacting and migrating on structured surfaces with imposed thermal gradients was investigated. It was observed that on an isothermal smooth surface, a lubricant droplet would impact, spread to a maximum diameter, and retract; while on a non-isothermal smooth surface, an asymmetric geometrical morphology of droplet was generated, accompanying with a migration process. Relevant dimensionless parameters were employed to evaluate the dynamic process, and the physical mechanism was revealed. Decorating surfaces with convergent microgrooves pattern could not only increase the maximum spreading diameter but also accelerate the migration process. These are beneficial for the heat exchange efficiency and lubrication performances. [DOI: 10.1115/1.4052779]

Knowledge mapping analysis of the track and hotspot of water lubrication: A scientometrics review

Abstract: Abstract With the enhancement of environmental protection awareness of the international community and the continuous promotion of green and sustainable development of manufacturing industry, water lubrication instead of mineral oil has become the future development trend due to its green, pollution-free, clean, safe, and sustainable advantages especially in ships, marine, coal mining, and other fields. In recent years, with the rapid development of water lubrication research, significant progress has been made in related research knowledge domain and discipline. A systematic and extensive assessment of water lubrication research has become increasingly important. The objective of this research is to reveal the research status, research hotspots, and development trends in the field of water lubrication. Therefore, CiteSpace was used to conduct a systematic bibliometric and scientometrical analysis of 1,792 publications from Web of Science core collection database (1997–2021). The results show that China and USA are the most productive countries in the field of water lubrication and have made outstanding contributions. Through the analysis of hot key words and co-citation references, this paper reviews the research status of water lubrication in three aspects: (1) lubricating medium modification; (2) material preparation; (3) surface optimization. It has become a research hotspot to promote the superlubricity contact interface and the application of nanotechnology. The results of this study can make a significant contribution to the development of water lubrication by providing a comprehensive understanding of the research status and research hotspots in this field. Personal understanding and discussion of research hotspots and research status are expected to provide insights into future research trends. In addition, this study will provide valuable references and guidelines for researchers who are interested in this field.

A sulfonated modification of PEEK for ultralow friction

Abstract: Abstract Polyether ether ketone (PEEK) is a widely used material for friction pairs due to its excellent mechanical strength, good wear resistance, and chemical inertness. However, some modifications are necessary when PEEK is used as a water-lubricated friction pair. In this study, a novel sulfonation method was developed to design a water-lubricated friction pair with ultralow friction, good wear resistance, and high loading capacity. PEEK powders were sulfonated using ClSO 3 H and sintered to form bulk plastic. The sulfonated PEEK (SPEEK) plastic exhibited good tribological properties. At a low sliding speed, the friction coefficient was smaller than 0.02 when a 3 wt% NaCl solution was used as the lubricant. The order of magnitude of the wear rate was as low as 10 −8 mm 3 /(N·m). The mechanism of friction reduction was mainly hydration lubrication. The negatively charged −SO 3 − groups on the friction pair can adsorb hydrated Na + cations by electrostatic interactions. These hydrated Na + cations have a high load capacity and low shearing resistance. The ultralow wear mechanism observed in this study is possibly due to ultralow friction properties of the friction pairs prepared through the proposed sulfonation and thermoforming procedures.

Study on Friction and Wear Properties of 23CrNi3Mo Carburized Steel under Water Lubrication

Abstract: In this paper the friction and wear of 23CrNi3Mo carburized steel under water lubrication were studied. The friction and wear properties of carburized steel sliding with stainless steel, GCr15, Al2O3 and ZrO2 balls were analyzed by tribometer, 3-D topography and SEM. The results show that compared with other materials, ZrO2 and carburizing steel have better tribological properties. Compared with Al2O3, the wear depth of carburized steel sliding with ZrO2 is reduced by 41% at the load of 2 N and 50% at the load of 10 N. In the load range of 2N-10N, the wear rate of carburized steel is the lowest when rubbing with ZrO2, and it gradually decreases when the load increases. Combined with SEM and Raman spectrum analysis, Oxide film was formed on the surface of carburized steel during the sliding test of ZrO2 and carburized steel. This oxide film was mainly composed of Fe3O4 and Fe2O3, which effectively reduces the friction coefficient and wear rate of 23CrNi3Mo carburized steel under water lubrication.

Structural design and magnetic field analysis on magnetic fluid lubricated bearings

Abstract: A structural model of a bearing is proposed based on a general standard bearing structure and magneto-fluidic lubrication, and the magnetic field of the bearing lubrication gap is analyzed under the action of an applied magnetic source. Results show that the magnetic field can form a magnetic circuit in the bearing structure, and a significant magnetic flux density is formed in the contact area of the rolling element of the bearing. The magnetic induction intensity in the contact area of the rolling element of the thrust bearing can provide magnetic fluid lubrication, and the magnetic induction intensity in the contact area of the rolling element of the point contact bearing is greater than that of the linear bearing. The magnetic inductance of the rolling elements in the rolling element contact area of a double row point contact bearing is greater than that of a single ring. The double permanent magnet ring structure has a more advantageous magnetic field effect than a single ring, and the magnetic inductance in the rolling element contact area of both rows of a double row point contact bearing is relatively the same.