Hongmei Wang

Determination of mechanical properties of ultra-thin films by nanoindentation and nanoscratch techniques

As new engineering coatings get ever thinner and more technologically advanced, there is an increasing demand for accurate assessment of the mechanical properties of the thin films, for instance ultra-thin carbon layers on magnetic heads, electronic pads for MEMS and LB films. The rapidly expanding field of depth-sensing evaluation and techniques related provides a quantitative method for mapping the micro mechanical properties. A new type of nano test system was introduced, the technology principle and the data analysis metho0d were described. It was used to test the performance of thin films on silicon wafer, steel and glass prepared by many kinds of technologies, this included nanoindentation, to evaluate the mechanical properties, such as hardness, elasticity modulus, and nanotopography to test the thickness and roughness, and nanoscratch to investigate the scratch resistance as well as the deformation and failure behaviour of the films. The results show that nanoindentation and nanoscratch techniques are very useful tools in charactering the performance of thin films in nano scale.

Applications of Nanoindentation Techniques in the Field of Surface Coatings

As new engineering coatings get ever thinner and more technologically advanced, there is an increasing demand for accurate assessment of the mechanical properties of thin films. The rapidly expanding field of depth-sensing evaluation and techniques related provides a quantitative method for mapping the micro/nano mechanical properties. A new type of nano test system was introduced, the technology principle and the data analysis method were described. It was used to test the performance of brush-plated nanocomposite coatings, supersonic plasma-sprayed coatings and self-repairing microcapsule for corrosion-proof coatings, including the distribution of mechanical properties across the surface and the section and nanoindentation creep. The results show that nanoindentation techniques play an incomparable role in charactering the performance of surface coatings.

Remanufacturing Technology Innovation for Second-Hand Computer

The volume tendency of in-use and second-hand computers in China were analyzed, the emerging danger of second-hand computers by incorrect treatment was summarized, the integration disposal technologies based on remanufacture and reuse technology aiming at monitors, electronic devices, metals, plastics materials, and overall computers were put forward, the economic and social benefits were also analyzed. The results show that the integration disposal process of second-hand computer is an optimum approach to save the resource of electromechanical products. Remanufacturing and disposal 100 thousands second-hand computers per year could create profits about ￥10 millions and provide employment for 300 persons. It can be deduced that there are great potential opportunities for the second-hand computers disposal industry containing recycle, remanufacture and reuse engineering.

Nano Surface Engineering and its Applications

The nano surface engineering technology mainly concludes the nano-materials electric brush plating technology, nano-materials thermal spraying technology and nano-films solid lubrication technology. Through the nano surface engineering, the films or coatings possessing the nano-structure characteristics can be prepared, improving remarkably the wear-resistance, anti-corrosion and fatigue-resistance of the substrate. Although the nano surface engineering enriches the maintenance methods and advances the maintenance effects, it still stands the elementary development period and many fundamental issues deserve to research in depth.

Advanced Rapid Forming Technology for Remanufacturing Engineering

Based on the foreign remanufacturing mode, the new remanufacturing rapid forming technology, which relies mainly on Surface Repair and Performance Improving Method has been explored and practiced. The aim of remanufacturing forming is to renew the original size of the waste components rapidly, and then improve their service performance. The advanced rapid forming technology, especially the high density heat source surface forming technology, is the important technique to carry out rapid forming. Based on the arc heat source, plasma heat source and laser heat source, three kinds of high density heat source remanufacturing forming technologies, such as high speed arc spraying forming technology, micro-arc plasma forming technology, and laser cladding forming technology, have been developed.