Corrosion of Potential First Stage Blade Materials in Simulated Supercritical CO₂

Figures & data

Figure 1. Principles of a power conversion system [3].

Figure 2. Various power conversion efficiencies [3].

Table 1. Composition based on EDX outputs (wt.%) [17].

Wt%	Ni	C	Co	O	W	Ta	Cr	Ti	Al	Zr	Y	Hf
CM247	57	0.07	8.1	-	9.5	3.2	6.4	0.7	5.6	-	-	-
SC2464 ERC/ BC	Bal	-	16.1	4.1	-	-	10.9		6.4	-	-	-
8YZS TBC	Bal	-	-	18.6	-	-	17	-	10	54.7	0.3	1.3

Figure 3. Simple schematic of a furnace [18].

Figure 4. Averaged weight change plot showing mass change vs exposure time for test 1 and 2; (a) Metal change for 800 °C/1 bar/CO₂ + 2.7 mol% H₂O + 0.17 mol% O₂ and (b) Metal change for (b) 800 °C/1 bar/CO₂ + 1.43 mol% N₂ + 0.17 mol% O₂ + 300 ppm SO_2.

Figure 5. Dimensional metrology for tests (a) 1 and (b) 2.

Table 2. K_p values where the exposure time was 1000 h. (Units are mg²/cm⁻⁴.s⁻¹).

X^2 = Kpt +C	CM247	CM247 + SC2464	CM247 + SC2464 + 8YSZ
Test 1	0.004	0.00004	0.0001
Test 2	0.0003	0.0002	0.0002

Figure 6. SEM micrographs of CM247. (1), (2) and (3) represent the unexposed samples of CM247, CM247+SC2464, and CM247+SC2464+8YSZ. respectively. (a) and (b) CM247 at 1000 h for test 1 and 2. respectively, (c) and (d) CM247+SC2464 at 1000h for test 1 and 2. respectively. whilst (e) and (f) CM247+SC2464+8YSZ at 1000h for test 1 and 2. respectively.

Figure 7. Backscattered and EDX maps for test 1 exposed for 1000 h. (a) CM247, (b) CM247 + SC2464, and (c) CM247 + SC2464 + 8YSZ.

Figure 8. Backscattered and EDX maps for test 2 exposed for 1000 h (a) CM247, (b) CM247 + SC2464 and (c) CM247 + SC2464 + 8YSZ.

Table 3. EDX analysis composition (wt.%) of CM247 exposed for 1000 h in test environment 1 (C excluded from analysis).

CM247	Ni	Cr	Al	O	Co	Ti	W	Ta
Point 1	61.8	9.1	5.3	0.9	9.9	0.6	9.0	3.4
2	64.9	6.2	6.1	1.2	7.7	0.9	8.4	4.5
3	61.8	8.9	5.3	1.2	9.7	0.7	9.4	3.0
4	62.4	8.1	5.1	1.7	9.6	0.6	9.1	3.3
5	46.1	9.2	13.4	13.6	8.6	0.2	6.9	2.0
6	2.5	0.6	-	3.4	0.3	8.0	11.6	73.5

Table 4. Elemental composition of CM247 in test environment 2 (wt.%).

CM247	Ni	Cr	Al	O	Co	Ti	W	Ta
Point 1	60.3	9.7	5.4	0.5	10.3	0.6	10.3	2.9
2	64.0	7.3	5.4	0.4	10.1	0.6	9.5	2.7
3	64.4	7.7	5.9	0.4	9.7	0.7	8.1	3.1
4	59.1	7.9	7.7	8.5	8.5	0.8	6.1	1.5
5	31.8	6.8	18.4	25.2	4.7	1.4	5.6	6.1

Note that this data has been corrected to exclude carbon from all spectra.

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