  Cold spray coatings are the sum of countless individual bonding events
between single particles impacting on top of one another at high velocities.
Thus, the collective behavior of microparticles must be considered to elucidate
the origins of coating flaws at the scale of the particles and larger, or the
dynamic evolution of the overall coating microstructure. Laser-induced particle
impact testing (LIPIT) has been extensively used to study single-particle
impacts, and in this work is adapted to study the accumulation of numerous
particles with knowledge of each individual particle's impact parameters
(particle size, velocity). The method reproducibly deposits stacks of gold
particles (>20 particles) with different characteristic spectra of impact
velocity. The observation of impact-induced erosion lets us define a critical
velocity for material-build-up that is higher than that for single-particle
bonding. The quantitative single-particle data are analyzed in a correlative
manner to the structure and flaws in the resulting stacks, providing some first
statistical connections between, e.g., strain and recrystallization, or
aberrant particle characteristics and defects. The results highlight
opportunities for the study of many-particle phenomena in microparticle impact
-- from interaction of particles in cold spray to multi-step erosion processes
-- with a quantitative view of the behavior of single particles.
