A two-step glass-ceramic coating process employing laser radiation

D. Correa-Coyac, A. Ramos-Velazquez, A. Michtchenko, R. Zenteno-Garcia, N. Shchedrina, Y. Karlagina, T. Itina, A. Tokmacheva-Kolobova, S. Manohin, D. Lutoshina, R. Yatsuk, G. Odintsova
Instituto Polit├ęcnico Nacional,
Mexico

Keywords: glass-ceramic, coating, hydrophilic, laser radiation

Summary:

Lasers are sophisticated diagnostic and technological tools that have found increasing application in the field of thermal spraying. This work aims to report the integration of two different laser applications (laser texturing and laser firing) to deposit glass-ceramic coatings on a metal surface and their final mechanical properties. First, a nanosecond pulsed Ytterbium fiber laser is used to fabricate nanostructures with different parameters of power density, time pulse, and overlapping, then a powdered glass-ceramic material is sprayed on the textured surfaces and dried. Last a pulsed CO2 laser is used to heat the glass-ceramic enamel and form a coating with distinct mechanical, anti-erosion and anti-corrosion properties compared with untextured materials. Laser texturing is a single-step method used to control the surface roughness of a metallic substrate under ambient conditions. Metallic alloys such as steel and titanium are popular materials with constant studies due to the wide range of biomedical, aeronautics and industrial applications. Different micro- or nanostructures can be produced providing certain properties to the surface, which can be used to modify its wetting behaviour, after laser radiation, the textured materials show a diffractive aspect and a significant surface morphology change. Super-hydrophilic surfaces have attracted great attention due to their large variety of applications such as cell-cell manipulation, heat transfer, biomolecular immobilization, drag reduction and improvement of coatings. The glass-ceramic powder material from the system SiO2-Na2O-ZnO-CaO-B2O3-Al2O3-CoO is characterized using energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM) and grain size analysis, then is sprayed above the nanotextured specimen and dried at ambient temperature. Laser firing is another single-step method to heat and melt the glass-ceramic films, to form a glass-ceramic coating. It is also important as laser texturing, to define the parameters of power density, time pulse and overlapping that can provide optimum films. Morphology and chemistry of laser-textured surfaces were characterized using SEM, XRD, XPS.