An Investigation of Phase Crystallinity in Laser Modified Yttria Stabilized Zirconia (YSZ) Thermal Barrier Coating

Abstract:

This paper presents laser surface modification process of plasma sprayed yttria stabilized zirconia (YSZ) thermal barrier coating (TBC) for enhanced hardness properties and low surface roughness. A 300W JK300HPS Nd: YAG laser was used to process YSZ TBC sample surface. The parameters selected for examination were laser power, pulse repetition frequency (PRF) and residence time. Micrographs of the TBC system were captured using EVO 15 Scanning Electron Microscope (SEM). Surface roughness was measured using 2-dimensional stylus profilometer. X-ray diffraction analysis (XRD) was conducted to measure phase crystallinity of the laser-modified coating surface. X-ray diffraction patterns were recorded in the 2θ range of 10 to 80° using Bruker D8 Advance system with 0.7Å wavelength from a copper source (~1.5Å). The laser modified surface exhibited higher crystallinity compared to the as-sprayed samples. The presence of tetragonal phase was detected in the as-sprayed and laser processed samples. The hardness properties of laser modified TBC increased 15% of the as-sprayed sample. These finding are significant to development of thermal barrier coating design optimization for enhanced surface properties of semi-solid forming die.

References

[1] G. Di Girolamo, F. Marra, C. Blasi, E. Serra, T. Valente, Microstructure, mechanical properties and thermal shock resistance of plasma sprayed nanostructured zirconia coatings, Ceramics International, Volume 37, Issue 7, September 2011, Pages 2711-2717, ISSN 0272-8842.

DOI: 10.1016/j.ceramint.2011.04.024

[2] Amit Srivastava, Vivek Joshi, Rajiv Shivpuri, Rabi Bhattacharya, Satish Dixit, A multilayer coating architecture to reduce heat checking of die surfaces, Surface and Coatings Technology, Volumes 163–164, 30 January 2003, Pages 631-636, ISSN 0257-8972.

DOI: 10.1016/s0257-8972(02)00690-4

[3] Reza Ghasemi, Reza Shoja-Razavi, Reza Mozafarinia, Hossein Jamali, The influence of laser treatment on thermal shock resistance of plasma-sprayed nanostructured yttria stabilized zirconia thermal barrier coatings, Ceramics International, Volume 40, Issue 1, Part A, January 2014, Pages 347-355, ISSN 0272-8842.

DOI: 10.1016/j.ceramint.2013.06.008

[4] M.F. Morks, C.C. Berndt, Y. Durandet, M. Brandt, J. Wang, Microscopic observation of laser glazed yttria-stabilized zirconia coatings, Applied Surface Science, Volume 256, Issue 21, 15 August 2010, Pages 6213-6218, ISSN 0169-4332.

DOI: 10.1016/j.apsusc.2010.03.143

[5] Raheleh Ahmadi-Pidani, Reza Shoja-Razavi, Reza Mozafarinia, Hossein Jamali, Improving the thermal shock resistance of plasma sprayed CYSZ thermal barrier coatings by laser surface modification, Optics and Lasers in Engineering, Volume 50, Issue 5, May 2012, Pages 780-786, ISSN 0143-8166.

DOI: 10.1016/j.optlaseng.2011.12.007

[6] Jan Ilavsky, Judith K. Stalick, Phase composition and its changes during annealing of plasma-sprayed YSZ, Surface and Coatings Technology, Volume 127, Issues 2–3, 22 May 2000, Pages 120-129, ISSN 0257-8972.

DOI: 10.1016/s0257-8972(00)00562-4

[7] H.G. Scott, Phase relationships in the zirconia-yttria system, J. Mater. Sci. 10 (1975) 1527-1535.

[8] G. Laukaitis et al., Deposition of YSZ Thin Films Using Electron Beam Evaporation Technique, MATERIALS SCIENCE (MEDŽIAGOTYRA). Vol. 11, No. 3. 2005, ISSN 1392–1320.

[9] C. O. Paiva-Santos et al, Surface Roughness Effect on the B's Values in the Rietvield Refinement. The Crystal Structure of La1-φ Srφ MnO3 (φ ≈ 0. 35), LabCACC tips on the Rietveld Method. Publication #1.

[10] Dongsheng Wang, Zongjun Tian, Lida Shen, Liu Zhidong, Yinhui Huang, Effects of laser remelting on microstructure and solid particle erosion characteristics of ZrO2-7wt. %Y2O3 thermal barrier coating prepared by plasma spraying, Ceramics International, http: /dx. doi. org/10. 1016/j. ceramint. 2014. 01. 101.

DOI: 10.1016/j.ceramint.2014.01.101