SiC纤维表面(BN-SiC)_n复合涂层的制备及单丝拉伸性能

Preparation of (BN-SiC)_n composite coatings on SiC fibers and tensile properties of monofilament

为制备出理想的连续纤维增韧陶瓷复合材料界面相,利用化学气相沉积(CVD)工艺在SiC纤维表面连续制备出三种类型的(BN-SiC)n复合界面涂层,对其进行微观结构表征,并通过单丝拉伸测试研究不同涂层对纤维单丝拉伸性能的影响。结果表明:SiC纤维表面沉积的(BN-SiC)n涂层较为均匀致密。单丝拉伸强度随着涂层层数的增加而降低。单层BN涂层的SiC纤维具有最高的单丝强度保持率(70%)和最大的拉伸伸长率(2.3%)。具有(BN-SiC)1与(BN-SiC)2复合涂层的SiC纤维单丝的拉伸性能相比原始SiC纤维有明显下降,拉伸强度保持率分别是42.1%和32.3%。

In order to prepare an ideal interphase of continuous fiber reinforced ceramic composite,three types of(BN-SiC)ncomposite coatings were deposited on the surface of SiC fibers by chemical vapor deposition(CVD).The microstructure of the(BN-SiC)ncoatings was characterized.The monofilament tensile properties of SiC fibers with various(BN-SiC)ncoatings were investigated.The results show that the(BN-SiC)ncoatings deposited on the SiC fibers are dense and uniform.The tensile strength of SiC fibers monofilament decreases with the increasing coating layers.The SiC fibers with single BN coating have the high monofilament strength retention of about 70%and the maximum elongation of about 2.3%.Compared to the original SiC fiber,the monofilament tensile properties of SiC fibers with(BN-SiC)1 and(BN-SiC)2 composite coatings decrease obviously,and the tensile strength retention rates are 42.1%and 32.3%,respectively.