1 / 21

Corrosion Testing of HVOF Thermal Spray Coatings

Corrosion Testing of HVOF Thermal Spray Coatings. By: Stephen P. Gaydos Boeing – St. Louis 20 February 2002. Chrome Plate Baseline. #1 Problem is QQ-C-320 Has No Corrosion Resistance Requirement Ferroxyl Porosity Test (Allows 15 pits/150 sq.in.) Why No Corrosion Testing In QQ-C-320?

ulema
Download Presentation

Corrosion Testing of HVOF Thermal Spray Coatings

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Corrosion Testing of HVOF Thermal Spray Coatings By: Stephen P. Gaydos Boeing – St. Louis 20 February 2002

  2. Chrome Plate Baseline • #1 Problem is QQ-C-320 • Has No Corrosion Resistance Requirement • Ferroxyl Porosity Test (Allows 15 pits/150 sq.in.) • Why No Corrosion Testing In QQ-C-320? • Chrome Plate Contains Cracks and Porosity and Could Not Pass a Corrosion Test • Chrome Plate Appears to Work O.K. in Severe Service Environments So Corrosion Testing Never Added as Requirement

  3. HVOF Corrosion Testing • What Criteria Do You Use for HVOF? • Can’t Use QQ-C-320 So Create Your Own • Put in Salt Spray and Look for Red Rust (Most Popular Criteria Being Used) • Tells You if You Have Base Metal Corrosion • Put in Salt Spray and Look For Any Signs of Corrosion – Base Metal or Coating • Currently Under Investigation • Conduct Electrochemical Testing • Potentiodynamic, Potentiostatic, EIS, etc.

  4. HVOF Sample Prep • 1018 Steel - 1” O.D. Bar • Grit Blast • Apply per BAC 5851 • St. Louis Metallizing • SM Diamond Jet & TAFA JP5000 • Powders - WC-17Co • SM 2005 (Normal) & 2006 (Fine) • TAFA 1343VM (Normal) & 1343VF (Fine)

  5. HVOF Sample Prep (Cont.) • Powders - WC-10Co-4Cr • SM 5847 • TAFA 1350VM • Thickness 3 to 5 mils • As Sprayed and Ground to 8 micro inch • Sealers • Metco Seal AP and URS

  6. Chrome Plate Prep • 1018 Steel - 1” O.D. Bar • Grit Blast • Chrome Plate per PS 13102 (QQ-C-320) • 2 to 3 mils thick • Two Different Plating Vendors Used • Optional Ni Underplate Applied At 1.5 mils • As Plated (No Grinding) • Sealers • Metco Seal AP or URS • IMPCO RC-80 per PS 11501

  7. HVOF Specimen Prep

  8. HVOF Test Specimens (Before) TAFA/1350VM/8uin DJ/5847/8uin

  9. Corrosion Tests • Salt Spray Tests • ASTM B117 - Neutral Salt Spray • ASTM G85 - SO2 Salt Spray • Electrochemical Tests • Determine Corrosion Rates (mils per year) • Potentiodynamic • EIS

  10. Salt Spray Test Results

  11. 5% NaCl Salt Spray Results for Chrome Plating Cr Plate 2 Weeks = Cr Plate 2 Days = Cr* Plate 1 Week = Cr* Plate 2 Weeks = *Cr Plate Vendor #2

  12. SO2 Salt Spray Results for Chrome Plating 1 Week for Cr* Plate 2 Days for Cr Plate *Cr Plate Vendor #2

  13. Salt Spray Results for Ni/Cr Plating 30 Days in 5% NaCl Salt Spray 30 Days in SO2/NaCl Salt Spray

  14. 5% NaCl Salt Spray Results for HVOF Coatings 4 Week Exposure = For WC-Co TAFA/1343VM/8uin TAFA/1343VF/8uin DJ/2005/8uin DJ/2006/8uin 4 Week Exposure For = WC-Co-Cr DJ/5847/8uin TAFA/1350VM/8uin

  15. SO2 Salt Spray Results for HVOF Coatings Two Day Exposure = For WC-Co TAFA/1343VM/8uin TAFA/1343VF/8uin DJ/2005/8uin DJ/2006/8uin One Week Exposure For = WC-Co-Cr TAFA/1350VM/8uin DJ/5847/8uin

  16. Electrochemical Test Results

  17. *Cr Plate Vendor #2

  18. *Cr Plate Vendor #2

  19. *Different Cr Plate Source

  20. Conclusions • Not All Chrome Plate Behaves The Same In Corrosion Tests • Sealing Helps Chrome Plate But Does Not Appear to Help HVOF Coatings • HVOF WC-10Co-4Cr Has Better Corrosion Resistance Than WC-17Co • Nickel Underplate With Chrome Plating Has Superior Corrosion Resistance

More Related