PSI - Issue 64

Hideki Oshita et al. / Procedia Structural Integrity 64 (2024) 48–55 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

53

6

Table 1. Analytical parameters

specimen

S-A5-F500

S-A10-F500

500

frequency(Hz)

5

10

current(A)

power per unit area(W/m 2 )

274.7

1098.9

Corrosion protection area(m 2 )

0.094

150mm

200mm

200mm

Circular spiral coil

Round bar diameter:16

Fig. 6. Analytical model

Protective inducedcurrent density

logarithm

logarithm

0.01 1 100 1.0 10 2 A/m 2 10 -2

200 1.E+00 1.E+03 1.E+06 1.0 10 3 10 6

kA/m 2

0.01 1 100 1.0 10 2 A/m 2 10 -2

200 1.E+00 1.E+03 1.E+06 1.0 10 3 10 6

400 360 320 280 240 200 160 120

Upper region

Upper region

3 10 -2

6 10 -2

160

160

1.8 10 5

3.6 10 5

120

120

Middle region

Middle region

1A/m 2

1A/m 2

80

80

1A/m 2

1A/m 2

80 40 0

40

40

Lower region

Lower region

0

0

mm

mm

Fig. 7. (a) Distribution of protective induced current density (S-A5-F500); (b) Distribution of protective induced current density (S-A10-F500)

The test specimen is shown in Fig.8. To verify the corrosion prevention effect using the analysis parameters set in the previous section, we fabricated a test specimen with the same shape and dimensions as the analytical model. The objective was to quantitatively evaluate the corrosion prevention effect of this method against microcell corrosion. The iron reinforcement used in the experiment had its passive film removed by immersing it in a 10% citric acid solution for one week as pretreatment. Electromagnetic induction was conducted for 30 days in a temperature controlled and humidity-controlled chamber at 20°C, followed by daily spraying with a 5% sodium chloride solution to accelerate corrosion degradation. Additionally, to compare the corrosion prevention effect of electromagnetic induction, we performed the same pretreatment and corrosion acceleration method on the test specimen S-A0-F0 without applying electromagnetic induction.