ZrC涂层及其复合涂层的制备和性能研究

【作者】 刘岗；

【导师】 李国栋；

【作者基本信息】 中南大学 ， 材料学， 2011， 硕士

【摘要】 为了进一步提高炭/炭(C/C)复合材料的抗冲刷耐烧蚀性能,本研究在C/C复合材料表面制备了ZrC或者ZrC/SiC复合涂层作为防护涂层。采用ZrCl4-CH4-H2-Ar反应体系,冷态输送ZrCl4粉末化学气相沉积(CVD)制备ZrC涂层。通过热力学计算,结合实验结果,分析了低压冷态输送ZrCl4化学气相沉积ZrC涂层的特点,选用X射线衍射(XRD)、能谱分析(EDS)和扫描电镜(SEM)等现代测试手段研究了工艺参数(温度、氢气流量、碳锆比、沉积压力、沉积位置等因素)对ZrC涂层的物相组成、表面形貌和断面结构的影响,从而优化了制备工艺。利用纳米压痕和DR6130氧乙炔焰烧蚀实验分别研究了不同结构涂层的力学性能和烧蚀性能。利用SiC过渡涂层缓解ZrC涂层和C/C复合材料之间的热匹配问题。研究结果表明：冷态输送ZrCl4粉末大幅度降低了ZrC的化学气相沉积温度,且容易获得大面积、结构均匀的ZrC涂层。随着温度的升高、氢气流量的增加、C/Zr比和压力的减小,炭含量减少,涂层(200)晶面择优生长增强,致密度增加,硬度和弹性模量分别增加了11.67和6.32倍,线烧蚀率和质量烧蚀率大幅度减低。而沉积速率则随着温度的升高、C/Zr比的增加而增大,随着氢气流量的逐渐增加先变大后变小。初步认定制备ZrC涂层最佳工艺参数为：温度为1450～1600℃;C/Zr为1:1;C/H≤1/15;压力为3-5KPa。复合涂层的线烧蚀率相对于单一ZrC涂层的没有太大变化,但质量烧蚀率却减小了73%,并且,烧蚀裂纹变小。可知,SiC过渡层在一定程度上缓解了ZrC涂层与C/C复合材料的界面处的内应力。更多还原

【Abstract】 To improve anti-ablation behavior of the C/C composite, this reaserch deposited the ZrC or ZrC/SiC film for the protect film on the C/C composition. ZrC film was deposited by chemical vapor deposition with ZrCl4-CH4-Ar system, and ZrCl4 was transported in solid. The characters of the so-prepared ZrC film were analyzed by chemical thermodynamics calculating and experimenting. The effects of preparation parameters on the composition, surface morphology and microstructure of ZrC coating were studied by X-ray diffractometry, energy dispersive spectroscopy and scanning electron microscopy and so on, such as deposition temperature, H2 gas flux, C/Zr ratio, deposition press and deposition position, and set down the perfact preparation technics. The mechanical behavior and the ablation behavior of the different microstructures were studied respectively by nano-indetation test and DR6130 oxyacetylene torch. The SiC film was regard as the transition flim to decrease the endogenetic force.The reasurch find as followed:the preparation method in this reasurch falls down the chemical vapor deposition temperature. And it is easy to get widespread、homogeneous ZrC film in structure. With the tempreture going up, H2 gas flux increasing, C/Zr ratio decreasing and deposition press decreasing, C content decreases, the crystal plane (200) of ZrC film grows preferentially, the density increases, the rigidity and elasticity simulation increases respectively 11.67 and 6.32 times, ablation ratio in line and mass decreases respectively by a large margin than the worse. The deposition ratio goes up with the tempreture and the C/Zr ratio increasing. However, the deposition ratio increases firstly, and then decreases with the H2 gas flux increasing. The results show that the perfact preparation technics in preparating ZrC film:the tempreture: 1450～1600℃; C/Zr=1; C/H≤1/15; The deposition press:3-5KPa. Relative to the single ZrC film, the composite film changes unconspicuous in ablation ratio in line, but decreases 73% in ablation ratio in mass, and diminish in ablation crack. As a result, the SiC film regards as the transition flim decrease the endogenetic force between the ZrC film and the C/C composition.更多还原