The Microstructure and Wear Resistance of a Copper Matrix Composite Layer on Copper via Nitrogen-Shielded Arc Cladding
A TiN and TiN·Ti2Cu reinforced copper matrix composite layer was cladded onto a T3 copper substrate to improve the anti-wear performance of copper products by means of the nitrogen-shielded gas tungsten arc cladding method (N2-GTAC). Better than the traditional preparation method of TiN, the TiN particles in the cladding layer were in situ generated using N atoms of shielding gas and Ti atoms of pre-deposited metal powders. In addition, the composite phase TiN·Ti2Cu occurred in the cladding layer, which also had a positive effect on anti-wearing. As Ti increased, the amount and grain size of TiN·Ti2Cu and TiN increased as a result. The hardness of the cladding layer increased with the increasing amount of reinforced phase generated in the layer. The hardness of the layer reached a maximum of 410 HV, which is nearly 5.1 times greater than that of copper. The TiN·Ti2Cu- and TiN-reinforced phases improved the wear resistance of the cladding layers. The cladding layer with 15 wt % Ti had the longsest launch stage (600 s) and the lowest fiction coefficient (0.56).
Characterization on laser clad nickel based alloy coating on pure copper
Abstract Nickel based alloy coating has been successfully deposited onto pure copper surface by laser cladding with coaxial powder feeding. Coating with thickness in the region of 1.5 mm can be obtained by depositing two layers of overlapping laser clad tracks. The microstructure observation from optical microscopy and scanning electron microscopy indicated that the coating was free of cracks and pores, and soundly bonded with the substrate. The X-ray diffraction analysis results showed that the coating was mainly composed of γ -(Ni, Cr, Mo, W) solid solution, some carbides and silicides. The average hardness of the coating was about HV 0.1 360, which was about 5 times that of the pure copper. The dry sliding wear tests showed the wear resistance of copper was significantly improved after laser clad nickel based alloy coating.
"Flying Triangulation" - a new optical 3D sensor enabling the acquisition of surfaces by freehand motion
In order to obtain complete 3D surface information of an object it is often necessary to acquire many partial 3D views. For this purpose, the sensor has to be moved (e.g. for the acquisition of sculptures or rooms). Further, in many cases a motion of the object relative to the sensor is unintended but inevitable (e.g. for medical applications such as intraoral measurements of teeth). Nearly all existing optical 3D sensors either lack an easy handling or require a standstill during the acquisition of a single partial 3D view, since usually multiple camera shots have to be taken for this purpose. This makes such measurements elaborate or even impossible.