Round-robin Atom-probe Experiment : Preliminary Results in Japan

A round-robin experiment *re to be carried out by 6 laboratories in Japan (Nishikawa; Tokyo Inst. Tech., Sakurai and Igata; Univ. of Tokyo, Ishikawa; Hitachi, Tanino; Nippon Steel Corp. and Nakamura; Osaka MT.) under the normal operating condition (T<lOO°K,.~lse fraction-75%~~ Pc10' torr). Fe-Cr-Al and W-25%Re alloys, which are divided fran a single wire were chosen as the specimen materials. A prelimi~ry analysis of the W-Re alloy of the laboratory cxmemrd shw the good agreeinent with the expecting value even if it was under different experimental conditions. However the apparent concentration of the Fee-Al alloy shw different result and is found to depend on the haging gas (Ne) pressure even at the same pulse fraction and specimen temperature. The operating condition will be discussed to obtain accurate quantitative analysis of alloys in the atom probe. I mwm1ON There are many type of atcm prohes which are conventional linear type and the energy focusing type , gated imaging type and magnetic deflection type. The atan-probe instrument analyses a very small volum of the specimen. How accurately dose the atan-probe spectrum represent the actual ampsition of this volum? At the 25th and 26th IFS, round-robin atan probe experiment have already been presented before. These round investigated a ternary Molybdenum based alloy and alloy containing Silicon. In some atan probe microanalytical investigation of hanogeneous alloys, the apparent concentrations of certain element have been found to differ fran the expected values. For quantitative atan probe analysis of Silicon-containing alloys, it appears that a pulse fraction of at least 15% is required and the analysis inside the central ring of low index poles should be avided./'/ To cleare the present status of relative and absolute accuracies of the instnnnent, we have a co-operative research of ten groups in Japan. Preliminary results of six groups have been sumnerized. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1986270