模压技术制备C/C-BN复合材料的摩擦学特性

Sliding friction characteristic of C/C-BN prepared by mold-pressing

以h-BN、石墨、短切PAN炭纤维和酚醛树脂为原料,采用单向模压结合呋喃树脂浸渍炭化技术制备C/C-BN复合材料。在M2000型实验机上测试不同取向的C/C-BN试样与表面镀Cr的40Cr钢配副时的摩擦磨损行为。结果表明:在平行于压制方向的试样(试样1)中,抗压强度达82.43 MPa,高于垂直于压制方向试样(试样2)的(51.47MPa)。摩擦实验结果表明:随载荷增加,试样1、试样2的摩擦因数均先增加后降低,试样1的摩擦因数在120 N时达到峰值0.157,而试样2在100 N时达到峰值0.152;随载荷增加,试样1的体积磨损除150 N外,基本为增加态势,最高达2.07 cm3;而试样2的体积磨损则呈现三段式增加趋势,最高值为1.66 cm3。SEM形貌表明,在实验后,试样1的摩擦膜更完整、致密。其中,在60 N时,试样1的摩擦膜表层因粘着发生卷曲撕裂,而试样2则形成了网络状裂纹。

C/C-BN composite was prepared by mono-directional mold-pressing combined with funan-resin impregnated and carbonization using h-BN,graphite,short-cut PAN-fiber and phenolic-resin as raw materials.The sliding friction behavior of the samples with different orientations of C/C-BN against 40Cr steel ring coated with Cr was investigated in M2000 tester.The results show that the compress strength of samples consistent with pressing-direction(sample 1) is 82.43MPa,which is higher than that of the other samples with different orientation(sample 2) of 51.47 MPa.The friction results show that the coefficient of friction(COF) of two kinds of samples increase at first and then decrease with the increase of load.The highest COF value of sample 1 is 0.157 at 120 N,while that of sample 2 is 0.152 at 100 N.The volume wear loss of sample 1 increases with the increase of load which reaches the highest value of 2.07 cm3 at 200 N except that at 150 N,but that of sample 2 show a three-stage increase which reaches the highest value of 1.66 cm3 at 200 N.SEM images show that sample 1 has more integrated worn surface than sample 2 at the same tested-load.Some friction film of sample 1 is tore and curled at 60 N,while that of sample 2 has some network cracks.