**5. Conclusions**

In this chapter, a facile one-step method was developed for the production of Field's alloy nanoparticles or slurry using nanoemulsification technique. The composition, size, morphology, and thermal properties of as-prepared nanoparticles were characterized by XRF, TEM, and DSC, respectively. The slurry with modified Field's alloy nanoparticle dispersed in PAO or HFE7100 exhibits good thermal

properties and stability, which showed promising potential applications in cooling of electronic device, engines, and other systems. Meanwhile, an experimental study was performed to investigate jet impingement heat transfer of Field's alloy nanoparticles-HFE7100 slurry. The Field's alloy nano-PCM absorbed heat during a phase change process from solid to liquid phase coupled with HFE7100 evaporation process. The study showed that the mass fraction of nanoparticles played an insignificant role in pressure drop but an important role on heat transfer performance. The high heat flux removal capability had been demonstrated by repeated closed loop test. Away from the critical heat flux, Field's alloy nano-PCM slurry provided a significant heat transfer enhancement due to the increase in the thermal capacity of the carrier fluid. Moreover, the nano-PCM slurries were able to maintain 97% of their heat removal capability after 5000 thermal cycles.
