涂层碳纤维的抗拉强度与断裂特性

THE TENSILE STRENGTH AND FRACTURE PROPERTIES OF THE COATED CARBON FIBERS

利用化学气相沉积法在碳纤维表面获得ＳｉＣ、Ｃ＋ＳｉＣ、Ｓｉ、Ｃ－Ｓｉ梯度等涂层的基础上，研究了涂层对碳纤维强度的影响，分析了涂层及碳纤维原丝的相结构，观察了涂层碳纤维的拉伸断口形貌，并进一步探索了涂层碳纤维的断裂过程与断裂方式，实验结果表明：不同涂层碳纤维的强度各异，且其断口形貌与断裂方式也不尽相同.

In the paper,with the help of the CVD method,the authoracquired uniformSiC coatint,C+SiC composite coating,Si coating and C-Si gradient coatingon the surface of carbon fibers(CF);studied the influence of the coating on thetensile strength of CF; analysed the phase structure of the coating and studied thefracture process and fracture texture.Experimental results show that the tensilestrength of the coated CF is lower than that of the acetone treated CF;that thesequence of the tensile strength magnitude of the coated CF is from the C-Sigradient coated CF to the C+SiC composite ccated CF,tO the SiC coatedCF,and to the single Si coated CF;and that the phase structures ofall coatings on the surface of CF are noncrvstalline,The author further proved“the turbostratic graphite structure“ of the PAN Ⅱfiber,The characterizationsof appearance of the fracture of PAN fiber are the step form wave form,buckle form, car arm form,etc,respectively.The appearance of the fractureof the C-Si gradient coated CF,the C+ SiC composite coated CF and the SiCcoated CF is in the flat cutting form; the fracture mechanism is that the crazespreads throngh the CF. But the appearance of the fracture of the single Si coatedCF is in the pull-out form; the fracture mechanism is that the craze spreads alongthe interface of the coating,the CF is split.