球形钨粉的制备及应用

Preparation and Application of Spherical Tungsten Powder

以不规则形状钨粉颗粒为原料,采用射频(RF)等离子球化技术制备球形钨粉,并对球形钨粉进行铺粉及成形实验效果评价。在射频等离子球化过程中,研究球化工艺参数(送粉速率、送粉位置)和原料粉末形态对球化结果的影响。在铺粉实验方面,研究粉末特征和铺粉层厚对铺粉效果的影响。采用扫描电子显微镜、激光粒度分析仪和BT-100粉体综合特性测试仪对球化处理前后粉末的形貌、粒度、流动性、松装密度和振实密度进行测试和分析。结果表明:经过球化处理后,钨粉颗粒呈规则球形,表面光滑,球化率可达100%,流动性、松装密度和振实密度得到明显提高。球化率高的粉末流动性好,铺粉效果好;随着层厚的增加,铺粉效果逐渐得到改善;采用合适粒径的球形钨粉打印的钨薄壁件表面相对光洁,尺寸精度高。

The spherical tungsten powder was prepared by radio frequency plasma system with irregular tungsten powder as raw materials and the effect of spherical tungsten powder was evaluated by laying powder and forming result. In the process of preparing spherical tungsten powder, the effects of process parameters(feeding rate, feeding position) and raw tungsten powder on spheroidization results were studied. In the aspect of laying powder experiment, the effects of powder characteristics and layer thickness on laying powder effect were studied. The morphologies, particle size distribution, flowability, apparent density and tap density of the tungsten powder before and after spheroidization were characterized by scanning electron microscopy(SEM), laser micron sizer, BT-100 multifunctional powder physical property tester. The results show that tungsten powder is regularly spherical and has smooth surface after spheroidization, and the spheroidization rate can reach 100%. And the flowability, apparent density and tap density are improved obviously. The better the flowability of spherical tungsten powder with high spheroidizing rate, the better the effect of laying powder. With the increase of layer thickness, the effect of laying powder is improved gradually. And the thin-walled parts prepared by spherical tungsten powder with suitable particle size have low surface roughness and high dimensional accuracy.