Porous coated surfaces are found to enhance nucleate-pool-boiling Leaf transfer performance three- to tenfold compared to plane surfaces. However, with highly wetting liquids, boiling efficiency on porous surfaces usually suffers from thermal hysteresis phenomena at boiling incipience, which constrains engineering applications. The porous surfaces, characterized by a large number of cavities which can Be easily flooded by highly wetting liquids, typically have a larger temperature overshoot hysteresis (TOH) than do plane surfaces. Tn contrast, surfaces made of graphite-copper composite, a kind of nonporous enhanced material, are able to initiate nucleate pool boiling at relatively lower surface superheats. An experimental study of boding hysteresis phenomena is conducted by boiling pentane under the thermosaturated condition on graphite-copper composite surfaces with graphite fiber concentrations of 25% and 50%, and a pure copper reference surface. The immersion cooling start-up problem in electronic devices is simulated by reducing heat fluxes incrementally from the fully developed nucleate-pool-boiling state to various levels of preset minimum heat flux followed by a stepwise heat-up process. Results reveal that, in nucleate pool boiling, the hysteresis of boiling curves is considerably reduced with the use of graphite-copper composites in which micrographite fibers with ultra high thermal conductivity act as efficient nucleation activators and nucleus preservers. The ill-wetted character of graphite fiber tips helps compensate for the disadvantage of retardation in boding incipience.