13 research outputs found
Low Load Vickers Hardness Measurements of Nonconducting Materials in a Scanning Electron Microscope
Vickers hardness tests on microscopic small bodies, e.g., fibers, powder particles, thin layers, etc., require imprint dimensions near or even below the resolution limits of light microscopes. Hence, to detect and evaluate these miniature imprints a scanning electron microscope (SEM) has to be used. For such observations in a SEM, nonconducting samples have to be coated with a thin conductive layer. The influence of these films on the imprint size and thus on the hardness value can be rather significant. On the basis of a systematic investigation in the case of a layer much softer than the sample to be tested, methods for an elimination of the layer\u27s contribution to the hardness result are presented
Description of grain boundary-supported interdiffusion in thin films by an effective diffusion parameter
DETERMINATION OF THE GROWTH RATES OF Au2Al DIFFUSIONALLY FORMED IN THIN STEP-SHAPED Au-Al COUPLES
L'or et ses composĂ©s Au2Al et Au5Al2 prĂ©sentent des diffĂ©rences de rĂ©flectivitĂ© spectrale importantes dans le visible. Ces diffĂ©rences, observables Ă l'oeil nu, ont Ă©tĂ© utilisĂ©es dans un couple de couches minces Au-Al pour dĂ©tecter le mouvement vers la surface d'Au du front de phase des composĂ©s formĂ©s par diffusion. A partir d'une sĂ©rie continue de tels couples Ă©vaporĂ©s avec des Ă©paisseurs diffĂ©rentes sur le mĂȘme support, c'est-Ă -dire des couples de diffusion en forme de marche, avec un rapport atomique total 2Au/Al, les vitesses de croissance ont Ă©tĂ© dĂ©terminĂ©es. La tempĂ©rature de recuit nĂ©cessaire Ă©tait comprises entre 333 et 373 K. Les valeurs des vitesses de croissance sont en parfait accord avec des donnĂ©es rĂ©centes de la littĂ©rature, seulement dans la partie la plus Ă©paisse du couple : D = 2,1 exp(-1/kT) cm2 /s ; des vitesses lĂ©gĂšrement plus Ă©levĂ©es ont Ă©tĂ© obtenues dans la partie la plus mince.Gold and its compounds Au2Al, Au5Al2 show marked differences in their spectral reflectivity in the visible range. These differences, observable with the naked eye, have been used to detect the approach of the phase front of diffusionally grown compounds against the gold surface of a Au-Al thin film couple. From a continuous sequence of such couples evaporated in different thicknesses onto the same substrate, i.e. a step-shaped diffusion couple, of a total atomic ratio 2Au/Al, the growth rate constants were obtained The temperature for the diffusion anneal ranged from 333 to 373 K. Excellent agreement with recent literature data for the rate constants was found only in the thicker part of the couple : D=2.1 exp(-1/kT)cm2/s whereas the thinner part showed slightly higher rates