Status of AFRL characterization of Thermal Sprays for Engine Applications April 2, 2003 Robert Ware (937) Air Force Research Laboratory Susan Hill (937) John Ruschau (937) Nick Jacobs (937) University of Dayton Research Institute Robert Ware (937) Air Force Research Laboratory Susan Hill (937) John Ruschau (937) Nick Jacobs (937) University of Dayton Research Institute

2 Thermal Sprays for Engine Applications Study Objectives –Compare Performance of HVOF and Plasma Sprayed Coatings at room and elevated temperatures Fatigue elevated temperature Delamination / Bond Strength Strain to Fracture

3 High Temperature Fatigue Study Limited Fatigue Testing 0.010” thick coatings Detailed AFRL Characterization of a few points from PEWG Matrix

4 High Temperature Fatigue Results Steel, 300  F

5 High Temperature Fatigue Results Inconel 901, 750  F

6 Delam / Bond Strength Study Delamination after Loading, as a function of Life ½ inch thick Flat Bars to facilitate bond button testing Measured by Immersion Ultrasonics (UT), Fluorescent Penetrant Inspection (FPI), and Bond Button Test Two thicknesses (3 mils, 10 mils) Five coatings – HVOF: WC-Co; Cr 3 C 2 -20(Ni,Cr); T-400 – PS: WC-Co; T-400

7 Sulzer Metco (#9-2) untested sample (calibration) 100% reflection (no delamination) “good” 0% reflection (total delamination) Nondestructive Inspection (NDI) for Delamination of Fatigue Specimens Ultrasonic Immersion Testing (Pulse Echo) –10 MHz, 0 deg, 0.25” probe diameter, 1” focus –reflections from back wall show integrity of near wall NDI for Delamination, Previous Results

8 9-2, Std (Untested) WC-Co-Cr NDI for Delamination, Previous Results WC-Co Delamination Inspection, R = -1, 160 ksi 3, ksi; R = -1, # , ksi; R = -1, #9-9 WC-Co-Cr delaminates earlier than WC-Co

9 9-2, Std (Untested) WC-Co-Cr NDI for Delamination, Previous Results WC-Co ksi; R = -1, # ksi; R = -1, # ,000 cycles Delamination Inspection, R=-1, 185 ksi, 100 and 1000 cycles 1,000 cycles WC-Co-Cr delaminates earlier than WC-Co

10 Delam / Bond Strength Study Loading in fatigue in 4pt Bend No area variation observed in ultrasonic inspection FPI showed cracking in thicker PS coatings

11 Delam / Bond Strength Study Ultrasonic Inspection Results 4pt loading: Uniform attenuation observed –next steps correlating to bond strength correlating to metallurgical mounts condition

12 Delam / Bond Strength Study Fluorescent Penetrant Inspection Results 4 Point Loading: FPI showed cracking in thick Plasma Sprayed WC-Co & T400 –tension & compression –70 ksi, 1000 cycles no cracking in others WC-Co T ” 0.003”

13 Delam / Bond Strength Study Loading in Axial Tension Testing underway

14 Delam / Bond Strength Study Ultrasonic Inspection Results Axial Loading Area variation as observed previously –next steps correlating to bond strength correlating to metallurgical mounts condition

15 Strain to Fracture Study Strain to Fracture (STF) Measured by Acoustic Emission in Axial Tension Two substrates (17-22; Inco 901) Three temperatures (R.T., 300F, 750F) Two thicknesses (3 mils, 10 mils) Five coatings – HVOF: WC-Co; T-400; Cr 3 C 2 -20(Ni,Cr) – PS: WC-Co; T-400

16 Strain to Fracture Study Test Setup Oven Transducer

17 Strain to Fracture Study Sample Output Correlate loading to coating cracking events –load, stress, strain and time stamp –acoustic emission events: intensity, location, time stamp

18 Thermal Sprays for Engine Applications Study Status –High Temperature Fatigue Testing Complete Characterization of failed coupons ongoing –Acoustic Emission Setup & Testing Imminent –Bond Testing of Delaminations Altering Loading to try to induce delaminations