No abstract

Titanium carbide particle reinforced metal-matrix composite coatings, formed on duplex (austenitic/ferritic) stainless steel castings, were studied. These coatings, developed for wear applications, develop a functional gradient structure through a self-propagating high-temperature synthesis (SHS) of titanium carbide (TiC). This SHS-reaction was ignited in reactive inserts by the heat of liquid steel. The reactive inserts were compressed from mixtures of titanium, carbon and molybdenum powders together with iron or duplex stainless steel powders. The coating microstructure depends on the reactive insert composition. Molybdenum reduced the TiC particle diameter, and reducing the binder content reduced the areal fraction of TiC.On uuritud titaankarbiidiosakestega tugevdatud metallmaatrikskomposiitidest pinnete formeerumist roostekindlast (austeniit/ferriit) dupleksterasest valanditel. Kulumiskindel, funktsionaalse gradientstruktuuriga metallmaatrikspinnete karbiidne (TiC) faas moodustus iseleviva kõrgtemperatuursünteesi toimel. Süntees käivitus valuterase kõrge temperatuuri (1650 °C) toimel. Paksude gradientpinnete

Electrical conductivity of MWNT filled polymer composites can strongly depend on the dispersion of the filler. Injection moulding of the same nanotube filled conductive composite materials can lead to significant differences in conductivities while the corresponding morphological changes seem to be moderate. Here we report on a conductive atomic microscopy (C-AFM) study of a series of polycarbonate/MWNT settings injection moulded with different injection speeds and melt temperatures, completed with optical microscopy, SEM and TEM characterization. C-AFM was found to be able to visualize the significant differences in the morphology of electrical pathways in cross section. These morphological variations seem to correlate to the differing volume resistivity data and are in agreement with the expected structural effects of injection moulding processes with different parameters.