在石墨基体上脉冲电镀TiB_2镀层

Pulse Current Plating of TiB_2 Coatings on Graphite Substrate

采用KF KCl K2 TiF6 KBF4 和LiF KF NaF K2 TiF6 KBF4 熔盐体系 ,利用直流和脉冲电源在石墨基体上制备了TiB2 镀层。采用金相显微镜观察了镀层的厚度 ,用X射线衍射分析了镀层的组成 ,用扫描电镜观察了镀层的表面形貌。实验结果表明 :在LiF KF NaF K2 TiF6 KBF4 熔盐体系 ,当K2 TiF6 ∶KBF4 为 1∶4(摩尔比 ) ,脉冲电流幅度为 0 .45A·cm- 2 ,脉冲宽度为 85ms,脉冲间隔为 1 7ms时 ,得到的镀层致密、无裂纹、与基体的结合力很好、有金属光泽、TiB2 的纯度高。

TiB_2 coatings were prepared onto graphite substrate from KCl-KF-K_2TiF_6-KBF_4 and LiF-NaF-KF-K_2TiF_6-KBF_4 melts by direct current and pulse current. The TiB_2 deposits were identified by X-ray diffraction analysis and the thickness was evaluated by means of metallurgical microscope. The morphologies of the coatings were observed by scanning electron microscope. The results show that the deposited coatings have better adhesion to the substrate, high TiB_2 content, metallic brightness, compact surface without cracks. When the following conditions are used: the solvent is a fluoride mixture (LiF-NaF-KF 39.5∶10∶35.5 (mol)) with solutes K_2TiF_6 and KBF_4 in molar ratio of 3 to 12, pulse width is 8.5 ms, pulse interval is 1.7 ms, the average of pulse current density is 0.45 A·cm -2.