Boron　carbide/boron　nitride　(B4C/hBN)　ceramic　composites,　prepared　by　hot-pressing　sintering　as　pin　samples,　were　coupled　with　ductile　iron　disks　(QT)　in　air　on　a　pin-on-disk　tribometer.　The　influences　of　mass　fraction　(0%,　10%,　20%　and　30%)　of　boron　nitride　and　normal　loads　(5　N,　7　N,　10　N)　on　tribological　performance　of　each　friction　couples　were　investigated.　The　morphology　features　of　friction　surfaces　were　observed　with　scanning　electron　microscope　and　the　compositions　of　friction　surfaces　and　worn　debris　were　measured　by　Energy　dispersive　spectrometer,　X-ray　photoelectron　spectroscopy　and　X-ray　diffraction.　The　results　indicate　that,　at　5　N　load,　the　friction　coefficients　of　B4C/hBN　ceramic　composites　with　0%　and　10%　mass　ratio　of　hBN　(BN00,　BN10)　and　QT　couples　were　high　up　to　0.5.　In　contrast,　when　hBN　contents　reached　20%　and　30%　(BN20,　BN30),　the　friction　coefficient　were　reduced　to　0.2.　The　tribological　mechanism　of　QT-BN00　couple　was　mainly　adhesive　wear　and　severe　plastic　deformations　was　observed　on　worn　QT　disk.　A　continuous　surface　film　was　discovered　on　BN30　worn　surface　and　the　main　tribological　morphology　of　the　coupled　grey　cast　iron　was　mild　micro-cuttings.　With　the　increasing　normal　load　(7　N,　10　N),　the　wear　mechanism　of　QT-BN00　and　QT-BN10　was　adhesive　wear　with　comparable　friction　coefficients　to　that　at　5　N　load.　However,　as　test　load　increased,　the　film　formed　on　BN30　worn　surface　was　damaged,　resulting　in　the　rise　of　the　friction　coefficient.　The　friction　coefficient　increased　to　0.6　at　the　load　of　10　N,　indicating　that　the　addition　of　hBN　had　no　improvement　on　lubrication.　©　2016,　Science　Press.　All　right　reserved.