NaCl包覆/氢化脱氢联合法制备超细钛粉及其性能

Fabrication and properties of ultrafine Ti powder by NaCl coated/hydrogenation-dehydrogenation combined method

以海绵钛为原料,采用经过氢化破碎、阻止剂包覆、真空脱氢以及阻止剂脱除的方法制备超细钛粉。采用TEM、SEM以及激光粒度测试等手段研究制备过程中工艺参数对钛粉形貌、粒度及氧含量的影响,探讨阻止剂的晶粒长大抑制机理。结果表明：海绵钛在700℃、2 h渗氢后经过球磨5 h,粉末中位径（D50）达到2.61μm,以NaCl为阻止剂对氢化粉末进行包覆,经630℃、2 h脱氢并脱除阻止剂后,制得的超细钛粉呈不规则形状,中位径达6.16μm,氧含量为0.89%（质量分数）;阻止剂的引入造成钛粉氧含量的微量增加;通过阻止剂包覆,在粉末颗粒表面形成厚度为5~10 nm的隔离层,阻碍了加热过程中Ti颗粒表面的原子扩散,从而阻止加热脱氢过程中粉末颗粒的长大。

Ultrafine Ti powder was prepared through the process of hydrogenation,mechanical pulverization,inhibitor coated,vacuum dehydrogenation and inhibitor removed with titanium sponge as its raw materials.The effects of technological parameters on the morphology,particle sizes and oxygen content of Ti powders were investigated by transmission electron microscopy,scanning electron microscopy and laser-diffraction diameter tester,etc.The mechanism of NaCl inhibitory action was explored.The results show that the titanium hydride powder with D50 of 2.61 μm is obtained after the hydrogenation at 700 ℃ for 2 h and then mechanical pulverization for 5 h.Using NaCl as inhibitor to coat the titanium hydride powder,dehydrogenizing at 630 ℃ for 2 h and removing NaCl,an irregular Ti powder with D50 of 6.16 μm and oxygen content of 0.89%（mass fraction） is prepared.There is not a noticeable increase of oxygen content in the Ti powder after the addition of NaCl.The growth of Ti particles during the dehydrogenation is effectively inhibited through the coating treatment of NaCl which forms isolation layer of 5-10 nm thickness on the surface of Ti particles to the block surface atomic diffusion.