Study On SiC Coated Carbon Fibers And Its Reinforcement Of Oil Well Cement

SiC coated carbon fibers have been successfully fabricated by spark plasma sintering.The crystal structure of SiC was investigated by X-ray diffraction(XRD),the microstructure and surface morphology of SiC coated carbon fibers was measured by scanning electron microscope(SEM),and its contained functional group was examined by Fourier transform infrared spectrometer(FTIR),the anti-oxidation behavior of SiC coated carbon fibers was measured by a differential scanning calorimeter(DSC-TG).By adjusting the experimental parameters and the proportion of ingrediant,the test results show that when the temperature to 1250? and the dosage of silicon powders is 10 wt.%,the fabricated Si C coated carbon fibers presents the best performance.The SiC coated carbon fibers were added to oil well cement to prepare SiC coated carbon fibers reinforced oil well cement composites.The density and flow performance of oil well cement paste have a modest decline,but the API filtration have been improved.When the oil well cement stone is reinforced by pristine carbon fibers and SiC coated carbon fibers,its flexture strength increases with the dosage of SiC coated carbon fiber and curing time.When the oil well cement contains 5 wt.% pristine carbon fibers,its flexture strength reaches the maximum value.The 28-day flexture strength is 16.90 MPa,which is 264.9% higher than pure oil well cement.But when the oil well cement contains the same degree of SiC coated carbon fibers,its flexture strength can be improved obviously,the 28-day flexture strength is 22.83 MPa,which is almost 5 times higher than that of the pristine carbon fibers reinforced oil well cement.Additionally,after reinforced by the SiC coated carbon fibers,the cement composite has an improved deformation up to 34% and a compressive strength of 58.12 MPa,which is 68.75% and 41.76% higher than those of pure oil well cement,respectively.At last,the fractured surfaces of SiC coated carbon fibers reinforced oil well cement were investigated by SEM,and its microscopic reinforced mechanism were analyzed.