金属离子注入纳米结构和特性

FORMATION OF NANOSTRUCTURE AND ITS PROPERTIES BY METAL ION IMPLANTATION

材料中纳米弥散相的形成对材料强化有着非常重要的作用 ,离子注入技术在材料表面容易形成这种结构 .透射电子显微镜观察表明 ,经过 Ti注入的钢 ,表面形成了直径为 10～ 30 nm丝状的 Fe Ti和 Fe Ti2 相 ,其长度为 15 0～ 32 0 nm ,当束流密度分别为 2 5～ 5 0μA.cm-2 时 ,弥散相的密度分别为 1.2× 10 11和 6 .5× 10 10 cm-2 ,其平均直径则分别为 10和 18nm.扫描电子显微镜观察C+ Ti样品表明 ,注入后表面形成的抗腐蚀钝化层也为丝状纳米结构 ,细丝直径 2 5～ 6 0 nm,长度10 0～ 2 0 0 nm,密度约 2 .2× 10 9cm-2 .这种致密的结构具有很强的抗磨损特性和抗腐蚀特性 .抗磨损特性提高了 8倍 .电化学测量结果表明 ,随注量的增加 ,腐蚀电流密度 Jp 明显下降 ,用 3× 10 17cm-2 注量的 Ti注入 H13钢 Jp 比未经注入之值降低到 0 .12 5 %～ 0 .0 5 0 % ;W注入聚脂膜 (PET)形成了 10～ 2 0 nm W的析出相 ,这种相的析出使 PET表面硬度增加 ,抗磨损和抗腐蚀特性增强 。

The formation of dispersed phases is very important for material strengthening. The formation of dispersed phases can be obtained easily by ion implantation. TEM observation shows that after Ti implantation into steel, Filar phases of FeTi and FeTi 2 with size of 10~30 nm in diameter are formed in the implanted layer. The length of the phases is 150~320 nm. At ion flux of 25 μA·cm -2 and 50 μA·cm -2 , the density of dispersed phases is 1.2×10 11 cm -2 and 6.5×10 10 cm -2 ,respectively. The average diameter is 10 nm and 18 nm, respectively. SEM observation of sample C+Ti shows that the passivation layer against corrosion is filar nanostructure also. The diameter of the filar phases is 25~50 nm. Its length is 100~200 nm. The density of the phases is about 2.2×10 9 cm -2 . The dispersed strengthen structure has very good resistance to corrosion and wear. Wear resistance increases by 8 times. The results of multi sweep cyclic voltammetry show that corrosion peak current density J p increases obviously with increasing ion dose. When ion dose of 3×10 17 cm -2 is used, J p decreases to 0.15~0.05% compared with unimplanted steel. Tungsten precipitation phases with a size of 10~20 nm are formed in W implanted polymer, therefore the surface hardness and wear resistance enhance, and a conducting layer is formed in the implanted layer of polymer.