Experimental Investigation on Corrosion of Cast Iron Pipes

Table 5

Tafel slopes and corrosion rate.

Solution and time of measurement	Pipe	𝛽𝑎 (mV/decade)	𝛽𝑐 (mV/decade)	CR (mm/year)
Static tap water after one year	1	123.5	131	0.074
	2	116.9	118.85	0.12
	3	182	197	0.12
Aerated tap water after one year	1	207.6	215.5	0.286
	2	223.7	233	0.239
	3	179.9	187.3	0.303
Aerated solution of 3.5% NaCl after six months	1	82.4	84.5	0.69
	2	31	31.6	0.53
	3	29.1	29.7	0.6