Ablation Properties and Elemental Analysis of Silicone Rubber Using Laser-Induced Breakdown Spectroscopy

With laser-induced breakdown spectroscopy (LIBS), the elemental compositions of the room temperature-vulcanized silicone rubber and the high-temperature-vulcanized silicone rubber newly prepared samples were analyzed in this paper. The LIBS spectra showed that carbon (C), oxygen (O), aluminum (Al), silicon (Si), iron (Fe), and zinc (Zn) were contained in the samples, consistent with the energy dispersive X-ray spectroscopy (EDS) results. With scanning electron microscopy (SEM), the micromorphology and the depth of the ablation craters were observed. The craters’ sizes were only about $200\sim 400~\mu \text{m}$ , and there was nearly no difference between the hydrophobicity of the nonablated area and the ablated area, and the static contact angle of the craters was even larger than that of the nonablated area, meaning that the LIBS analysis was almost nondestructive. The depth of the ablation craters showed linearity relationship with the laser pulse number that would help a lot in the in situ analysis. Increasing the laser energy of the shot, the intensity of spectra lines of definite element and the electron number density would increase at the same time. The study result showed that the LIBS would be a promising element analysis technique of silicone rubber especially on line, and the composition of the composites could be clearly observed.