Electrodeposited Inconel and Stellite like Coatings for Improved Corrosion Resistance in Biocombustors

Transcription

1 Electrodeposited Inconel and Stellite like Coatings for Improved Corrosion Resistance in Biocombustors S. H. Vijapur T. D. Hall E. J. Taylor M. E. Inman M. Brady (ORNL)

2 slide 2 Problem/ Oppurtunity Advantages of state of the art combustion systems Higher Efficiency Challenge: Reduce CO 2 and poisonous gas emissions Lower Fuel Cost Requires higher operating temperatures Potentially requires the use of exotic process streams Supercritical CO 2 Supercritical Steam Must be durable to range of burnable materials Wood, Gas, Coal, Waste.! Need to develop novel material systems to durably perform in these environments

3 Direct Current Electrodepositable Materials (from Literature) slide 3 Ia IIa IIIa IVa Va VIa VIIa VIII Ib IIb IIIb IVb Vb VIb VIIb ο 1 H 2 He 3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 10 Ne 11 Na 12 Mg 13 Al 14 Si 15 P 16 S 17 Cl 18 Ar 19 K 20 Ca 21 SC 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 28 Ni 29 Cu 30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 36 Kr 37 Rb 38 Sr 39 Y 40 Zr 41 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 49 In 50 Sn 51 Sb 52 Te 53 I 54 Xe 55 Cs 56 Ba 57 La 72 Hf 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 Hg 81 Tl 82 Pb 83 Bi 84 Po 85 At 86 Rn Electrodeposition is a scalable cost efficient technique to obtain surfaces with controllable physical, catalytic, and structural properties. These properties can potentially be enhanced and cost effectively scale to production levels Eliaz, N., et al., Induced Codeposition of Alloys of Tungsten, Molybdenum and Rhenium with Transition Metals Modern Aspects of Electrochemistry 42 Springer, NY, (2008), p 191, Ch. 4

4 slide 4 Direct Current Electrodepositable Alloy Materials from Water Based Solution (from Literature) With Alloy materials the composition may also be varied to obtain the variance in the desired physical properties Electrical Resistance Wear Resistance Thermal Resistance Thermal Expansion Match Au X Pt Ir X Re X W X X Sb X X Sn X X X X In X X X Cd X X X X X X Ag X X X X X X X X X Pd X X X X Rh X X X X X X Ru X X X X Mo X X X X Zr X Se X X X X Zn X X X X X X X X X X X Cu X X X X X X X X X X X X X Ni X X X X X X X X X X X X X X X X Co X X X X X X X X X X X X X X Fe X X X X X X X X X X X X X Mn X X X X X X X X X X Cr X X X X X X X X X X X V X X X X X Ti X X X X X X Eliaz, N., et al., Induced Codeposition of Alloys of Tungsten, Molybdenum and Rhenium with Transition Metals Modern Aspects of Electrochemistry 42 Springer, NY, (2008), p 191, Ch. 4

5 slide 5 Global Initiative Create more efficient, longer lasting, cleaner, and cost effective cookstoves for use in burning biomaterials Why: Nearly 4.3 Million deaths a year are due to smoke inhalation Incomplete combustion producing CO and carcinogens Nearly $40 Billion spent annually on fuel sources Some families spend up to 2 hr a day or 1/3 of income acquiring fuel 1 Billion Tons of CO 2 year from open fires! Must improve burning efficiency! Must operate at higher temperatures! Must design low cost material systems to durably perform in these environments

6 slide 6 DOE Focus Program on Low Cost Coatings Problem: Biomass combustion reactors are subjected to various corrosive attacks due to the wide range of potential materials that will be burned in them, including: Gasoline, grass and other carbon based waste These give off mixtures of: Alkali halides (fly ash particulate) Halogen Acids Water Sulfur and Nitrogen Oxides Potential Solutions: 1. Replace the composition of the internal materials used within biocombustors. " Corrosion resistant SS, Ni Alloys, or Co alloys (THESE ARE COST PROHIBITIVE) 2. Apply a high value coating to existing bio-combustors or lower cost steels. " Coating could consist of corrosion resistant alloys like Stellite 21 or Inconel 740

7 slide 7 Objective of Program Develop a cost effective, scalable, and flexible electrodeposition based coating process that can be applied to the corrosion sensitive regions of existing and next generation bio-combustors Ni and Co based alloys have been shown to possess excellent alkali/ halide attack resistance Co based alloys have been shown to possess sulfidation resistance Mo additions into the metal alloys also seem to improve corrosion resistance and high temperature stability. Cr improves temperature stability and corrosion resistance in high temperature systems Alloy Co Ni Cr Fe Mo W Inconel (base) Inconel (base) Haynes 25 (base) Stellite 21 (base)

8 slide 8 Experimental Plan Outline Substrate: Low cost ferritic or austenitic steels 304 SS, 410 SS, 441 SS; 1 x 4 dual sided Coating compositions [Co/Ni] Cr [Mo/Fe] (composition variance) Testing Parameters: CTE (quick CTE test at Faraday within muffle furnace) Coating composition XRF High temperature corrosion test at 700 C in Air 500 hr Salt Spray (Remove after every 100 hr for weight and reapplication) High salt loading (3 mg/cm 2 ) and low salt loading (1 mg/cm 2 ) Cross-sectional SEM analysis of oxidation

9 slide 9 Electrolyte Development Used a Hull Cell to Rapidly design electrolyte and processing conditions to deposit binary and ternary alloys consisting of [Ni/Co]-Cr-[Mo/Fe] Used XRF to measure the deposit composition Standard Cr 3+ plating solution g/l CoSO 4 7H 2 O (0.077 M Co 2+ ) 4.8 cm Distance from high current edge, cm Elemental composition, % Cr Co Anode 6.3 cm Cathode cm Standard Cr 3+ plating solution g/l CoSO 4 7H 2 O (0.154 M Co 2+ ) Distance from high current edge, cm Elemental composition, % Cr Co

10 Compositional Screening: Ni-Cr and Ni-Co-Cr w/ Hull Cell slide 10 Hull Cell study shows that a wide range of potential deposit composition can be obtained controlling the Ni concentrations

11 Compositional Screening: Ni-Cr-Fe w/ Hull Cell slide 11

12 Compositional Screening: Ni-Co-Cr-Mo w/ Hull Cell slide 12 Alloy Co Ni Cr Mo Inconel (base) Stellite 21 (base)

13 slide 13 Scale up to 1 x 4 Coupons Using the electrolyte designed within the Hull Cell study and approximate applicable current densities we transitioned to coupon studies Cell 3: 1 x 4 samples prepared simultaneously 29 L cell Volume FARADAYIC Flow Assembly* Samples prepared Pure Ni (Wood s bath) Varying Thickness Pure Cr (1411 and 1318) Varying Thickness NiCr (Varying Ni Conc. / Thickness) NiCrFe (Thickness) NiCoCr and CoCr (Varying Thickness) 1411 *Gebhart, L.E., and Taylor, E.J., U.S. Patent 8,329,006, December 11, 2012.

14 As Plated Samples NiCoCr NiCr Ni: 25, Cr: 20, Co:55 NiCrFe CoCr Cr: 15, Co:85 slide 14 Cr: 20, Co:80

15 slide 15 Corrosion Studies Baseline 100 h salted oxidation [~3 mg/cm 2 - high salt loading and 1 mg/cm 2 low salt loading: sea salt applied to surface from 3.5 w/w% solution prior to corrosion test] Five consecutive 100 h salted oxidation Thermal Cycle Ramping from room temperature to 100 C at 10 C/min Dwelling at 100 C for 30 minutes Ramping from 100 C to 450 C at 1-2 C/min Dwelling at 450 C for 60 min Ramping from 450 C to 700 C at 10 C/min Dwelling at 700 C for 100 hours Ramping from 700 C to room temperature at 10 C/min

16 Comparison Between Substrates and Coated Parts after 500h Salted Oxidation Trials [1 mg/cm 2 ] slide 16 Surface Images Post 500 h Cycle Mass-Loss Post 500 h Cycle Ni Panels A/B 316 SS 304 SS Cross-Sections Post 500 h Cycle

17 Comparison Between Substrates after 500 h Salted Oxidation Trials with High Salt Loading [3 mg/cm 2 ] slide 17 Surface Images Post 500 h Cycle SS substrates 100h Salted oxidation Mass-Loss Post 500 h Cycle 500h Salted oxidation 500h Salted oxidation Ni 60Ni-40Cr 70Ni-20Cr-10Al

18 Comparison Between Substrates and Coated Parts after 500h Salted Oxidation Trials with High Salt Loading [3 mg/cm 2 ] slide 18 Surface Images Post 500 h Cycle SS441/1411/60Ni-40Cr SS441/1411/25Ni-20Cr-55Co Mass-Loss Post 500 h Cycle Coated 100h 500h Coated 100h 500h SS441/1318/60Ni-40Cr SS410/1318/60Ni-40Cr Coated 100h 400h Coated 100h 400h

19 slide 19 Corrosion Performance Overview Pure Cr and Ni deposit do not maintain adhesion during salted corrosion studies 60/40 ish NiCr and NiCoCr (25/55/20) mixtures seem to have the best corrosion resistance (dependent on thickness) Ternary (Ni/Cr/Fe) deposits did not maintain adhesion during oxidation study (presumably to CTE mismatch) Composition-Electrolyte Base Cr Cr Ni - Wood s plating NiCr NiCr NiFeCr NiFeCr CoCr NiCoCr Salted oxidation (500 h) P O P P ~ 50 w/w% NiCr alloys improve corrosion resistance of the base SS substrate by at least 70% potentially leading to a 3.4 fold cookstove lifetime improvement

20 slide 20 Baseline Economic Analysis for Exemplar Component Estimate using Cookstove Design from Literature Patent Application# PCT/US2013/ Bulk Wrought Material Pricing 0.61 ft 2 internal area exposed to biocombustor hot zone $/lb Density (lb/ in 3 ) Cost per Volume of Material ($/in 3 ) Cost per Area Assume 1/8 Thick Material ($/ ft 2 ) Cost of 0.61 ft 2 exemplar component (Fig Right) 718 IN $ $ 6.47 $ $ IN $ $ 5.58 $ $ Haynes 25 $ $ $ $ L SS $ $ 0.77 $ $ SS $ $ 0.46 $ 8.26 $ 5.04 Hastelloy C-22 $ $ 5.95 $ $ Stellite 21 $ $ $ $ Stellite 6 $ $ $ $

21 slide 21 Initial Electrodeposition Based Economic Analysis Base material cost: $5.04 Coating cost is a function of the number of units produced Coating Cost Estimate Patent Application# PCT/US2013/ Line No. Plant Parameters 10,000 Units 100,000 Units 1,000,000 Units 1 Cylinder Size 0.61 ft ft ft2 2 Run Time (sec) Total Units/Hr Total Hours worked per day Units/Day (24 hr.) Days worked per year Units/Yr. (348 days) 16, ,632 1,069,056 8 Plating Line Cost ($/unit) $0.48 $0.06 $ Material Cost ($/unit) $2.03 $1.29 $ Labor Cost ($/unit) $12.52 $1.56 $ Total Cost ($/unit) $15.03 $2.91 $1.69

22 slide 22 Overall Conclusions Demonstrated a wide range of [Co/Ni] Cr [Mo/Fe] alloy coating compositions can produced Demonstrated process scalability from a Hull Cell to flat coupons Demonstrated the potential of specific coatings to surpass 500 h accelerate high temperature corrosion testing 50 w/w% NiCr alloys improve corrosion resistance of the base SS substrate by at least 70% potentially leading to a 3.4 fold cookstove lifetime improvement Demonstrated that the process maybe an economically viable approach for improve cook stove biocombustor lifetimes Cost estimate for 50 w/w% NiCr coating is $2.93/ in 3 or $1.69 per 4 mil coating on a 0.61 ft 2 component produced at 1,000,000 units per year This would realize a 89% cost reduction compared to base IN625 materials

23 slide 23 Next Steps Evaluate the potential of other alloy systems Co-Ni-Cr Ni-Cr-Mo/W Addition of Si or Al to the deposit Validate performance in combustion test rigs at ORNL

24 slide 24 Special thanks to all our team members for their support THANK YOU FOR YOUR ATTENTION! QUESTIONS? Contact Information: Santosh Vijapur, Tim Hall, Maria Inman, or EJ Taylor Ph: