Prakt. Met. Sonderband 38 (2006) 237 
he actual 
The first 
acuum up 
the point 
stance is 
uantity of 
1ge of the 
> reaction 
toms are 
1 value of 
g further Form 
remains 
int B with Lm 
Fig. 6: Microstructure of completely internally oxidized Ag-Sn (2 at.% Sn) alloy at T=600°C 
and t=720min; (a) optical microscopy and (b) scanning electron microscopy 
The results of in- situ electrical resistance measurements in fig 7 reveal also the parabolic 
kinetics of the internal oxidation process that is in agreement with Wagnerian theory of 
oxidation for solid solutions [7-9]. Finally, time t. needed for the total internal oxidation of 
the alloy can also be determined form the resistance curve (Fig. 7). The comparison of it 
with that determined by the metallographic analysis (Fig. 2) shows also a good agreement. 
MO - - ——p—1- 820 
105 - - - El. Resistance R(t) | 
—— Temperature T(t) - 815 
100 
T=800°C ' 1840 
articles) 95 
90+ - 805 
— 85 iX . Zn 
G he Hi See Lgoo 
£ wn] a 
x 75 \ Internal Oxidation „795 
707 L 790 
ie 
785 
60 3 
J I, + ©. TERE PIERRE 
60 70 80 90 100 110 120 130 140 150 160 170 180 
P=705 ! Limin] 
Fig. 7: In-situ measurement of electrical resistance changes during internal oxidation of 
Ag-Sn (2 at.% Sn) alloy at T=800°C and tc = t"-t'~ 51 min 
a) b) 
wee