碳纤维增强聚酰亚胺复合材料表面梯度涂层制备与组织性能研究

在碳纤维增强聚酰亚胺基体上设计了Ni-Ni/Cr-WC/Co和PI-Ni/Cr-WC/Co两种表面梯度涂层,并对其进行微观组织分析和抗热震性能测试,结果表明,采用化学镀镍和超音速火焰喷涂复合工艺得到的Ni-Ni/Cr-WC/Co梯度涂层结构较为致密,与基体结合较好,涂层经300次热震后无明显变化;采用超音速火焰喷涂得到的PI-Ni/Cr-WC/Co梯度涂层结构疏松,与基体结合力差,涂层经273次热震后完全脱落.镀镍层与基体能够通过机械力和原子力结合,也可以与镍铬合金层通过冶金结合、机械嵌合结合,同时在缓解涂层应力等方面起到重要作用,从而有效提高了梯度涂层的结合强度.

Study on Process, Microstructure and Properties of Surface Graded Coating on C/PMR15 Composite

Two surface graded coatings on C/ PMR15 substrate, Ni-Ni/Cr-WC/Co and PI-Ni/Cr-WC/Co were designed. Microstructure and the ability of resistance thermal shock were tested. The results show that the Ni-Ni/Cr-WC/Co coatings by electroless nickel and HVOF are compacter, higher bond strength than the PI-Ni/Cr -WC/Co coatings by HVOF. The former can resist 300 thermal cycles and have no visible changes, while the latter fail through delamination after 273 thermal cycles. The main reasons are that the layer of electroless nickel can be combined with the substrate through mechanical and atomic forces, and also with the Ni-Cr alloy layer by metallurgic and mechanical reaction, in addition efficiently relax the stress of the coating, so the bond strength of the graded coating is increased.