Zirconium carbide (ZrC) with layered structure and nanoparticle morphology was prepared by sonication in an ethyl alcohol solvent. The morphology and saturable absorption properties of the ZrC were systematically analyzed. By using ZrC nanoparticle coated substrates as saturable absorbers, stable Q-switched 3 μm $\mathrm{Er}\text{:}{\mathrm{Lu}}_2{\mathrm{O}}_3$ lasers were realized. Pulse durations of 50 ns with pulse energies of 20 μJ and peak power of 0.4 kW are the shortest obtained with novel-material-based Q-switched lasers in the 3 μm wavelength range.