1 Nanostructured Functional Coatings of Iron Family Metals with Refractory. . .
29
Fig. 1.26 Anodic
polarization plots for coatings
Co(72.2)-Mo(24.1)-Zr(3.7)
(1, 2) and Co(76)-Mo(24) (3,
4) in media: 1 M Na 2 SO 4
pH 11 (1, 3) and 3% NaCl
pH 7 (2, 4)
Table 1.5 Corrosion indicators of testing materials in different media
Corrosion medium pH
Corrosion parameters
Electrolytic alloys
Co76-Mo24
Co72-Mo24-Zr4
3
i cor , A·cm −2
2·10 −4
3·10 −5
¨ cor , V
−0.42
−0.46
k h , mm·year −1
2.3·10 −3
3.1·10 −4
7 (3% NaCl)
i cor , A·cm −2
2.5·10 −4
2.1·10 −5
¨ cor , V
−0.2
−0.5
k h , mm·year −1
2.9·10 −3
2.2·10 −4
11
i cor , A·cm −2
8·10 −5
3·10 −5
¨ cor , V
−0.43
−0.47
k h , mm·year −1
9.3·10 −4
3.1·10 −4
Table 1.6 The exchange
current density of hydrogen at
the platinum and ternary alloy
coatings
lg i 0 ° , A/cm 2
Composition of alloy, ω, at.% Ó° 3 Ó° 5 Ó° 9.5
Pt
−3.3 −3.2 −3.1
Fe51Co36Mo13
−3.1 −2.8 −4.0
Fe31Co31Mo38
−3.1 −3.6 −3.4
Fe54Co36W10
−3.5 −3.4 −3.3
Fe59´Ñ33W8
−3.3 −3.1 −3.5
1.1.4.3 The Catalytic Properties of Fe-Co-W, Fe-Co-Mo, and Co-Mo-Zr
Coatings
Results of testing the catalytic activity of Fe-Co-W, Fe-Co-Mo, and Co-Mo-Zr alloy
coatings in the model reaction of hydrogen evolution from different media (Tables
1.6 and 1.7) indicate the synergistic nature of the electrolytic alloys.
The values of the hydrogen exchange current density are related to the analogous
indices for platinum family metals, as one can see from Tables 1.6 and 1.7.
The exchange current density of hydrogen at binary and ternary alloys is higher
than this parameter on alloying components which can be attributed obviously with
the change in the mechanism of the process. From the literature [48], it is known