In this paper, we report on the dynamics of micro-jet impact and spreading on a solid substrate. The jets are the product of electrical discharge in a liquid confined to a capillary tube; the resulting spark creates a pressure impulse which rapidly deforms the concave meniscus into a fine jet ( \(d_{jet} \sim O(100)\,\upmu\) m) and then a heat-induced vapor bubble which expands and ejects more liquid from the end of capillary tube, as previously described in Rohilla and Marston (Exp Fluids 64:90, 2023) and Lawal et al. (Int J Pharm 674:125400, 2025). Here, we provide insight into the impact and spreading of these micro-jets across a range of fluid properties. We found jet speeds up to 81 m/s encompassing a wide range of Weber and Reynolds numbers (We \(\sim O(10^{1} {-} 10^{4})\) and Re \(\sim O(10^{1} {-} 10^{4})\) ), with different modes such as simple deposition, fine/early splash, and violent splashing. In accordance with previous reports on splashing in drop impact, we found that a modified Weber number based on the ejecta sheet, We \(= \rho \delta u_{ej}^{2}/\sigma\) , provides a concise way to delineate phenomena such as deposition vs. splashing, while maximum spreading is best described using, \(\beta _{\max } \sim \sqrt{\text{We}}\) .
