1. Reactive HVOF Spraying TiN-matrix Composite Coating and its Corrosion and Wear Resistance Properties Jing Ma Hebei University of Science and Technology September 2009

2. Outline 1. Introduction 2. Experimental methods 3. Results and Discussion 4. Conclusion 5. Acknowledgement 6. Papers

3. 1 Introduction Titanium nitride (TiN) coatings have promising properties. Preparation methods: physical vapour deposition (PVD) or chemical vapour deposition (CVD) reactive thermal spraying: high deposition efficient TiN coatings: Reactive Plasma Spraying

4. What is reactive thermal spraying? Combination of Self-propagating High Temperature Synthesis and Thermal Spraying Low cost; In-situ composite coating High density and bond strength Short process

5. My works TiN-matrix coating prepared by reactive HVOF (High Velocity Oxygen Fuel ) spraying Research of its corrosion and wear resistance

6. 2 Experimental Methods Sample preparation Substrate: Medium carbon steel (0.42- 0.50wt.%C steel) size : φ60×3mm Process: Ground ultrasonic cleaned sand blasted HVOF spraying

8. Measure methods Corrosion test: CHI600C electrochemical analyzer Wear test: MM type tester phases and composition: XRD/EDS Surface and cross-section morphologies: SEM/optical microscope Fig.1 illustration of wear test equipment

9. 3 Results and discussion Fig.2 XRD analysis of HVOF TiN-matrix composite coating The coating was consists of TiN, TiN0.3, Ti2O3 and TiO2

10. Fig.3 cross-section optical morphologies of HVOF spraying coatings  The coating was layer structure.  thickness of coating reaches at about 300μm.

11. Element Spectrum1 (at.%) Spectrum2 (at.%) Spectrum3 (at.%) NK=>11=<11 OK=>17- =>16 TiK=<72=>89 =<73 The light phase may be Titanium nitrides (TiN and TiN0.3) and the dark phase may be the mixture phase of Titanium nitrides (TiN and TiN0.3) and Titanium oxides (Ti2O3 and TiO2).

12. Fig.4 polarization curves of HVOF spraying TiN-matrix composite coating in 3.5wt%NaCl solution A board passivation zone

13. Tab.2 wear test result of HVOF TiN-matrix composite coating load 20kgf (without coating) 20kgf (with coating) 30kgf (with coating) 75kgf (with coating) Mass loss/g 1.58140.00130.00360.0021 Wear coefficient 0.640.49 0.50  wear coefficient of coating at different loads maintained a constant value.

14. Fig.5 surface and cross section morphologies of TiN-matrix composite coating (30kgf ): (a) surface morphology; (b) cross section morphology A At light load: particles spalled. (a) (b)

15. Fig.6 surface and cross section morphologies of TiN-matrix composite coating (75kgf ): (a) surface morphology; (b) cross section morphology At high load: layer fatigue spallation (a)(b)

16. two reactions in reactive spraying: The overlap of reaction heat and HVOF flame make TiN melting and deposit as TiN-matrix composite coating.

17. 1 2 3 The protective abilityof TiN-matrix composite coating prepared by reactive HVOF spraying in 3.5wt.%NaCl solution is excellent. TiN-matrix composite coating about 300μm thickness was prepared by reactive HVOF spraying, which has layer structure. The failure form of TiN-matrix composite coating at light loads is local spallation due to stress concentration while that at heavy loads is layer fatigue spallation. 4 Conclusion

18. 5 Acknowledgement Thanks for the open fund of State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology(KFJJ07-2). Thanks for Dr. Li and committee of this conference!

19. 6 papers ① Jing Ma ， Zhengping Mao ， Baode Sun ， Jun Wang. Microstructure and polarisation behaviour of TiN–TiB 2 matrix coating prepared by reactive plasma spraying. Materials Science and Technology, DOI 10.1179/174328409X443272 (SCI source). ② Zhengping Mao, Jing Ma, Baode Sun, Jun Wang. Properties of TiN-matrix coating deposited by reactive HVOF spraying. Journal of Coatings Technology and Research, 2009, 6 (2) 243–250 (SCI428JK) (EI20091612033022 ) ③ Zhengping Mao, Jing Ma, Jun Wang, Baode Sun. Comparison of the coatings deposited using Ti and B 4 C powder by reactive plasma spraying in air and low pressure. J Mater Sci (2009) 44:3265–3272 (SCI445GR) ④ Zhengping Mao, Jing Ma, Jun Wang, Baode Sun. Dry abrasion property of TiN- matrix coating deposited by reactive High Velocity Oxygen Fuel (HVOF) spraying. J. Coat. Technol. Res. DOI 10.1007/s11998-009-9180-6 (SCI source). ⑤ Zhengping Mao, Jing Ma, Jun Wang, Baode Sun. The effect of powder preparation method on the corrosion and mechanical properties of TiN-based coatings by reactive plasma spraying. Applied Surface Science, 2009, 255(6): 3784-3788(SCI387SO) (EI20090111825962 )