Critical heat flux (CHF) and pressure drop of subcooled flow boiling are measured for a microchannel heat sink containing 75 parallel 100 mu m x 200 mu m structured surface channels. The heated surface is made of a Cu metal sheet with/without 2 mu m thickness diamond film. Tests and measurements are conducted with de-ionized water, de-ionized water +1 vol.% MCNT additive solution, and FC-72 fluids over a mass velocity range of 820-1600 kg/m(2) s, with inlet temperatures of 15(8.6)degrees C, 25(13.6)degrees C, 44(24.6)degrees C, and 64(36.6)degrees C for DI water (FC-72), and heat fluxes up to 600 W/cm(2). The CHF of subcooled flow boiling of the test fluids in the microchannels is measured parametrically. The two-phase pressure drop is also measured. Both CHF and the two-phase friction factor correlation for one-side heating with two other side-structured surface microchannels are proposed and developed in terms of the relevant parameters. (C) 2011 Elsevier Ltd. All rights reserved.