水热沉积电压对ZrSiO_4抗氧化涂层显微结构及抗氧化性能的影响

Influence of Deposition Voltage on Microstructure and Oxidation Resistance of ZrSiO_4 Coatings Prepared by Hydrothermal Electrophoretic Deposition Process

以硅酸锆粉体为原料,异丙醇为溶剂,碘为荷电介质,采用水热电泳沉积法在C/C-SiC复合材料基体表面制备了硅酸锆外涂层。通过X射线衍射(XRD)、扫描电子显微镜(SEM)对涂层的晶相结构和微观形貌进行表征。研究了水热电泳沉积电压对涂层的显微结构及高温抗氧化性能的影响,并分析了涂层试样在1773 K下静态空气中的氧化行为。结果表明:电泳沉积电压在160～200 V范围内,复合涂层的致密程度、厚度及抗氧化性能随着沉积电压的升高而提高。但沉积电压过高(220 V),复合涂层中出现微裂纹等缺陷,此时涂层的抗氧化性能下降。沉积电压控制在200 V时所制备的复合涂层可在1773 K静态空气中有效保护C/C复合材料332 h,氧化失重率仅为0.2%,相应的氧化失重速率稳定在48.3μg.cm-2.h-1的极低水平。

ZrSiO4 coatings were deposited on the surface of C/C-SiC composite by a hydrothermal electrophoretic process using ZrSiO4 powder,isopropanol and iodine as raw materials,solvent and charging agent,respectively.The phase compositions and microstructures of the as-prepared multi-coatings were analyzed by X-ray diffraction and scanning electron microscopy.The influence of hydrothermal electrophoretic deposition voltage on the phase composition,microstructure and high temperature oxidation resistance of the multi-layer coatings was particularly investigated.And the oxidation behaviors of the as-prepared coated samples at 1 773 K were analyzed.Results show that the thickness and density of the ZrSiO4 coatings improve with the increase of deposition voltage from 160 V to 200 V,correspondingly with the increase of the deposition voltage,the increase in anti-oxidation properties of the coated samples is obvious.However,micro-cracks are found at a high voltage（220 V） in the preparation process and the oxidation resistance ability is weakened.The multi-layer coatings deposited at 200V exhibit the best oxidation resistance ability,which can effectively protect C/C composites from oxidation in air at 1 773 K for 332 h with a weight loss of 0.2% and the corresponding weight loss rate is only 48.3 μg·cm-2·h-1.