SiC-MoSi_2/ZrO_2-MoSi_2 coating to protect C/C composites against oxidation

To improve the oxidation resistance of carbon/carbon （C/C） composites in air at high temperatures, a SiC- MoSi2/ZrO2-MoSi2 coating was prepared on the surface of C/C composites by pack cementation and slurry method. The microstructures and phase compositions of the coated C/C composites were analyzed by scanning electron microscopy and X-ray diffraction, respectively. The result shows that the SiC-MoSi2/ZrO2-MoSi2 coating is dense and crack-free with a thickness of 250-300 μm. The preparation and the high temperature oxidation property of the coated composites were investigated. The as-received coating has excellent oxidation protection ability and can protect C/C composites from oxidation for 260 h at 1773 K in air. The excellent anti-oxidation performance of the coating is considered to come from the formation of ZrSiO4, which improves the stability of the coating at high temperatures.

Ni-ZrO_2复合电镀工艺的研究

研究了Ni ZrO2 复合镀液体系中微粒与镀液间的相互作用。镀液中的电解质NiSO4和NiCl2 对ZrO2 纳米微粒在复合镀液中的悬浮稳定性有很大影响。阴极极化曲线表明纳米微粒的加入改变了基质金属电沉积的过程。以高分子聚电解质作为分散剂 ,利用其在微粒之间形成的空间位阻效应 ,减弱镀液中离子对微粒的聚沉作用 ,得到了均匀分散的ZrO2 纳米微粒的复合镀镍溶液 。

Ni-ZrO_2复合镀层形成过程的研究

采用复合电沉积技术制备出了Ｎｉ－ＺｒＯ２复合镀层，并利用正交设计对影响复合电沉积过程的有关因素（包括电流密度、ＺｒＯ２微粒粒径、搅拌方式、镀液中微粒含量及其间的相互作用）进行了系统研究，镀液中ＺｒＯ２微粒表面荷电状况的分析表明，ＺｒＯ２微粒表面由于吸附了溶液中的Ｎｉ２＋而荷正电。