Effect of Nanocrystalline Diamond Films Deflection on Wear Observed in Reciprocating Sliding Tests

The present study deals with the tribological behavior of nanocrystalline diamond (NCD) films. The diamond films were deposited by microwave plasma enhanced chemical vapor deposition (MPCVD) in methane/hydrogen/air plasma on the Si(100) substrates. The tribological properties were studied by reciprocal sliding tests against Si3N4 balls. The depth profiles and surface morphology of the wear scars were investigated by means of mechanical profilometry and scanning electron microscopy (SEM). Various adaptation processes occur between contacting surfaces including asperity polishing, formation of carbonaceous tribolayer and ripple patterns on the wear scar surfaces. The film deflection is the specific form of adaptation decreasing contact pressure and, therefore, the damage (including wear) of both counter bodies. The deflection of NCD films in sliding tests can be related with the effect of fatigue

Recent progress and perspectives of space electric propulsion systems based on smart nanomaterials

Miniaturized spacecraft built from advanced nanomaterials are poised for unmanned space exploration. In this review, the authors examine the integration of nanotechnology in electric propulsion systems and propose the concept of self-healing and adaptive thrusters

Step flow observed on top of oxidized CoAl(1 0 0) surface

Clean and oxidized surfaces of CoAl(10 0) were investigated by Auger electron spectroscopy (AES), low energy electron diffraction (LEED), high resolution electron energy loss spectroscopy (HREELS), and scanning tunnelling microscopy (STM). The regrowth or step flow of terraces was observed at 1150 K. The correlation between the growth of oxide and the step flow on the CoAl(l 0 0) surface is discussed in this paper. (c) 2006 Elsevier B.V. All rights reserved

The coexistence of y(y') and (H) alumina observed by STM and LEED on top of oxide layer grown on CoAl(1 0 0)

We report the coexistence of gamma(gamma') and theta alumina grown on the CoAl(l 0 0) surface. Both phases were observed after annealing of alumina at 1150 K by means of scanning tunnelling microscopy (STM). The crystal structures of gamma(gamma') and 0 alumina were indexed based on low energy electron diffraction (LEED) and STM experimental data. (c) 2005 Elsevier B.V. All rights reserved

High temperature oxidation of CoAl(100)

We have employed Auger electron spectroscopy (AES), high resolution electron energy loss spectroscopy (EELS), low energy electron diffraction (LEED) and scanning tunneling microscopy (STM) to investigate the growth of an Al2O3 film on CoAl(1 0 0). While exposure to oxygen at room temperature leads to the formation of amorphous alumina, subsequent annealing at higher temperatures results in the growth of well-ordered theta-Al2O3. Well-ordered Al2O3 films are also formed by oxidation at temperatures of 800 K and above. The oxide is characterized by Fuchs-Kliewer modes at around 430, 630, 780 and 920 cm(-1). Oxide islands grow in two sets of domains perpendicular to each other. Under ultra-high vacuum conditions, self-limiting thickness of the oxide layer (9-10 Angstrom) has been found. The band gap of the theta-Al2O3 film on CoAl(1 0 0) is 4.3-4.5 eV. (C) 2005 Elsevier B.V. All rights reserved

Contact-mode scanning tunneling microscopy experimental technique employed for tunneling magnetoresistance measurements

We employed contact-mode scanning tunneling microscopy technique to perform systematic measurements of micrometer-sized Co/Al2O3/Co magnetic tunnel junctions (MTJs). Magnetic multilayer was grown by means of magnetron sputtering, followed by patterning of MTJ on top of FeMn antiferromagnetic bias layer into an array of rectangular mesa structures by standard photolithography. The maximum of 12.5% tunneling magnetoresistance at room temperature was measured for up to 40x40 mu m(2) test MTJs. (c) 2006 American Institute of Physics

Investigation of the ripple pattern formation on nanocrystalline diamond film surfaces during reciprocating sliding against Si₃N₄ balls

status: publishe