Wenping Jiang

Tribological Behavior of Deagglomerated Active Inorganic Nanoparticles for Advanced Lubrication

The tribological behavior of novel, deagglomerated, and active molybdenum disulfide (MoS2) nanoparticles as additives in paraffin oil is presented. In a novel approach, the MoS2 nanoparticles were activated by their intercalation with organic molecules, particularly triglycerides (canola oil) and lecithin (source of phosphorus). A four-ball tribological test setup was used to measure the wear scar diameter, the coefficient of friction, and the extreme pressure properties of such formulated paraffin oils. The results showed significant influence of this uniquely designed MoS2 nanostructured additive on the coefficient of friction (0.07), the wear scar diameter, and the extreme pressure (315 kg) properties of the paraffin oil. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive x-ray spectroscopy (EDS) were also used for investigating size, the surface morphology, and the elemental composition of the nanoengineered lubricant. The characterization revealed a particle size less than 100 nm and the elemental composition analysis of the wear track showed the presence of Mo, S, and P in the tribofilm, explaining the observed improvements in the tribological properties.

Nanostructured coatings for machining and wear-resistant applications

Nanostructured coatings offer great potential for various applications due to their superior characteristics that are not typicallyfound in conventional coatings. In this paper, the development and synthesis techniques of nanostructured coatings for machining and wear-resistance applications are reviewed.

Electrostatic Spray Deposition of Nanostructured Hydroxyapatite Coating for Biomedical Applications

Hydroxyapatite, a calcium phosphate ceramic, is chemically similar to bone mineral and one of the few materials able to produce direct-bonding osteogenesis. Nanostructured hydroxyapatite coating has proved effective in promoting cell growth. However, synthesis of the coating on components of complex geometries with controlled phases is still a challenge. In this paper, we present the results from the exploration of electrostatic spray coating of hydroxyapatite nanoparticles and the interaction of particles with laser. The nanoparticles were deposited on commercial grade titanium alloy (Ti6Al4V) as a coating perform and bonded using a transient laser heating process. The coating was characterized for its surface morphology, particle size, and adhesion, and analyzed for its chemical compositions and phases. Results have shown the potential of this process to address some of the issues present in the current synthesis processes.

Effects of CO2 Laser Surface Processing on Fracture Behavior of Silicon Nitride Ceramic

Surface defects generated by grinding deteriorate the flexural strength of the silicon nitride (Si 3 N 4 ) ceramic. In this paper, CO 2 laser surface processing was applied to eliminate the grinding-induced defects. SEM micrograph showed that the surface integrity of Si 3 N 4 samples was improved after laser processing. Four-point bending tests and fractographic analysis indicated that the flexural strength and fracture origins were affected by the change of surface integrity in laser-treated Si 3 N 4 samples. The effect of grinding-induced residual stress on flexural strength of laser-treated samples was discussed. It was concluded that laser surface processing had significant effects on fracture behavior of flexure Si 3 N 4 samples.