Of Fe Modified The Structure Of The C / C - Sic Friction Materials And Performance

Carbon/carbon-silicon carbide(C/C-SiC) friction material has a serialof advantages, such as, low density, good abrasive resistance, stablecoefficients of friction, excellent thermal shock stability, goodanti-oxidant and so on. So C/C-SiC friction material is a novel type ofmaterial developed in the new material field and used in the modernvehicles successfully.In order to improve coefficient of friction, through liquid silicon andiron infiltration, four kinds of Fe modified C/C-SiC friction materialswere made with the integrity felt as performs. Composite, morphology,interphase between fiber and matrix, images of worn surfaces and debriswere investigated by scanning electron microscopy (SEM), opticalmicroscopy (OM), X-ray (XRD). The mechanical properties includingbending property, compressive property, and shear property were studied.The friction and wear behaviors of Fe modified C/C-SiC friction materialwere tested on QDM150 frictional tester under different sliding velocityand pressure. The results show:1. With the increase of iron content, the mol rate of Fe:Si isgradually increased. Density is among 2.3～2.4g.cm^-3. C/C-SiCwithout iron (1#) is well densified and had low open porous rate(5.2%), and the connection between carbon fiber and matrix wasgood. With the increase of iron content, the open porous rate ofspecimens increased mildly.2. Different specimens have different mechanical properties. Themechanical properties become weaker and weaker with theincrease of iron content. The compressive strength of specimen1# is the largest (348.6MPa), while that of Modified C/C-SiCwith 15% iron is lowest 121.1MPa. Seeing from the morphologyof damaged area and loading-displacement curve, specimen 1#belongs to brittleness rupture.3. Coefficient of friction (COF) of C/C-SiC without iron declined firstly and then increased with in the increase of sliding velocity,and curve of wear rate is fluctuated. At the sliding velocity of16m·s^-1, COF is at lowest value (0.31), wear rate is 0.232×10^-7cm³·N^-1·m^-1; When the sliding velocity gets to 24m·s^-1, COF isat peak value (0.46), there is a transfer layer on the worn surface,the mechanism was mainly adhesive and oxidation wear.4. When sliding velocity is 8m·s^-1 and pressure is 1MPa, COFincreases firstly and then declines with the increase of ironcontent. Wear rate of specimen 4# with 15% iron reaches up to0.586×10^-7cm³·N^-1·m^-1, and the wear mechanism is adhesiveand oxidation wear.5. Specimen 2# with 5% iron has good friction and wear properties.COF is stable and comparatively high(0.37～0.54) and wear rateis low (0.119～0.589×10^-7cm³·N^-1·m^-1).