Nanosecond pulsed laser surface nanotexturing of tantalum: Correlation between diffusion length model and experimental observations

The diffusion length of surface textured tantalum using AVIA 355® nanosecond laser was correlated with the different laser parameters. The material was cut into 1 × 1 cm2 coupons and was exposed to the laser beam of various residence times. The surface of the tantalum coupons exhibited a material shape like peak/valley striations and attributed to the Gaussian profile of the laser beam. The surface textured tantalum coupons were examined under a MicroXAM 100 profilometer to create a 3D profile and measure the depth of the valleys of the surface. The different residence times of the laser beam had a significant effect on the diffusion length of the surface material. The diffusion length was further analytically validated, correlating diffusion length with the specific heat, thermal conductivity, and density of the material, as well as the laser residence time. The values were found to be within a 5% tolerance range that validates the experimental observations. The water droplet contact angle of the material was measured using drop shadow analysis to understand the change of the material properties after the surface texturing. In addition, a thermal model using comsol™ was developed to predict the effect of the residence time on the surface material. The experimental, analytical, and numerical analyses show very good agreement with each other and validate the hypothesis.