HeattransfercoefficientsinnucleateboilingonasmoothflatsurfaceweremeasuredforpurefluidsofR-134a,propane,isobutaneandtheirbinarymixturesatdifferentpressurefrom0.1to0.6MPa.Seriesofexperimentswithdifferentheatfluxandmixtureconcentrationswerecarriedout.Theinfluencesofpressureandheatfluxontheheattransfercoefficientfordifferentpurefluidswerestudied.Isobutaneandpropanewereusedtomakeupbinarymixtures.Comparedtothepurecomponents,binarymixturesshowlowerheattransfercoefficients.Thisreductionwasmorepronouncedastheheatfluxincreasing.Severalheattransfercorrelationsareobtainedfordifferentpurerefrigerantsandtheirbinarymixtures.