6.3 Pilling–Bedworth Ratio
155
Fig. 6.2 Schematic
representation of the bending
of a metal strip when the one
side of the strip is oxidized
to form a thin oxide film.
The oxide film with a value
of α PB > 1 or α PB < 1 is
subjected to compressive
stress or tensile stress,
respectively, and the
resultant bending of the strip
is convex or concave
Table 6.1 Values of α PB
calculated from Eq. (6.18) for
various metal/metal oxide
systems
Metal/Metal Oxide
α PB
Metal/Metal Oxide
α PB
Li/Li 2 O
0.44 *
Zn/ZnO
1.59
Be/BeO
1.70
Zr/ZrO 2
1.58
Mg/MgO
0.79
Nb/Nb 2 O 5
2.47
Al/Al 2 O 3
1.29
Mo/MoO 3
3.29
Si/SiO 2
2.15
Ag/Ag 2 O
1.58 *
Ca/CaO
0.63
Cd/CdO
1.42
Ti/TiO 2
1.77
α-Sn/SnO
1.02
V/V 2 O 5
3.32
β-Sn/SnO
1.29
Cr/Cr 2 O 3
2.02
α-Sn/SnO 2
1.05
Mn/MnO 2
2.34
β-Sn/SnO 2
1.33
Fe/FeO
1.77
Ba/BaO
0.68
Fe/Fe 3 O 4
2.08
Hf/HfO 2
1.59
Fe/Fe 2 O 3
2.14
Ta/Ta 2 O 5
2.33
Co/Co 2 O 3
2.42
W/WO 3
3.75
Ni/NiO
1.52
Pb/PbO
1.29 *
Cu/Cu 2 O
1.68
Pb/PbO 2
1.40
Cu/CuO
1.75
Bi/Bi 2 O 3
1.23
The numerical values of α PB with and without mark (*) in Table 6.1
were calculated from Eq. (6.18) by employing the values of ρ ox
for crystalline metal oxides in refs [9] * and [10], respectively