Etude par Sonde Atomique Tomographique de la formation de nano ...

tel-00751814, version 1 - 14 Nov 2012
Chapter 2. Materials, experimental and simulation techniques
amu without O2 + . So, chemical compositions of nanoparticles will be presented owing to both
assumptions (showing minimum and maximum level of Ti). For annealed and hot extruded
powder chemical composition of particles will be calculated taking into account TiO 2+
molecular ions located at 32 amu (presence of TiO 2+ molecular ions at 31, 31.5, 32, 32.5, 33
is clearly seen on mass spectrum, see on Figure 2.11.
Number of atoms
160
140
120
100
80
60
40
20
Figure 2.11. Mass spectrum of a hot extruded ODS steel obtained with LATAP.
As MA NDS steel are concerned, a mass spectrum of MA NDS steel annealed at
850°C/1h is shown on Figure 2.12 (a, b).
As it can be seen on Figure 2.12 (a, b), there is an overlap between
62TiN 2+ /62TiO 2+ /62Ni 2 at 31, 63TiN 2+ /63TiO 2+ at 31.5, 64TiN 2+ /64TiO 2+ /64Ni 2+ at 32 amu
(Figure 2.12 (b)). In this case, chemical composition of particles is calculated following these
assumptions:
46Ti 2+
47Ti 2+
48Ti 2+
49Ti 2+
50Cr 2+ - 50Ti 2+
52Cr 2+
0
22 23 24 25 26 27 28 29 30 31 32 33 34 35
Mass-over-charge-ratio (amu)
(a) Only N atoms are located at 14 amu (no Si atoms);
53Cr 2+
54Cr 2+ - 54Fe 2+
55Mn 2+
56Fe 2+
57Fe 2+
58Fe 2+ - 58Ni 2+
89Y 3+
60Ni 2+
61Ni 2+
62TiO 2+ - 62Ni 2+
63TiO 2+
64TiO 2+ - 16O2 + - 64Ni 2+
65TiO 2+
66TiO 2+
68CrO 2+
67