PRODUCTION OF NICKEL POROUS MATERIAL FOR ELECTRODE SUBSTRATE BY CO_2 LASER SINTERING

激光烧结已被用于生产镍多孔材料。采用最大功率为100W的连续模式CO2激光器作为热源，以镍粉为原料。镍粉的平均粒度为2.9~3.6μm。研究了激光功率、激光扫描速度、光束散焦和阴影间距等工艺参数对镍粉激光烧结的影响。采用激光照射镍粉的方法，在Ar气氛中制备了镍多孔材料。制备的镍多孔材料随着离焦量的增加而变得脆化。激光仅聚焦在粉末表面，即可得到良好的多孔材料。随着孵化间距的增加，镍多孔材料也变得脆化。孵化间距设置为0.05 mm时效果最佳。激光功率和激光扫描速度是制备镍多孔材料的重要参数。当激光功率较低、激光扫描速度较高时，由于单位面积的输入能量较低，多孔材料发生脆化。当激光功率较高、扫描速度较低时，由于单位面积的输入能量较大，多孔材料具有较大的孔隙率。观察到激光功率与激光扫描速度之间的密切关系。激光功率与激光扫描速度之间的最佳定量关系制得了良好的镍多孔材料。

Laser sintering has been done for producing a nickel porous material. CO_2 laser with maximum power of 100 W in continuous mode was used as a heat source and nickel powder was used as raw material. Average particle size of nickel powder was 2.9 - 3.6 μm. Influence of the processing parameter such as laser power, laser scan speed, beam defocusing and hatching pitch have been studied on the laser sintering of nickel powder. The nickel porous material was produced by irradiating laser beam to nickel powder in Ar atmosphere. The fabricated nickel porous material became brittle with the increase in the beam defocusing. Laser beam just focused on the powder surface produced the good porous material. The nickel porous material also became brittle with the increase in the hatching pitch. The hatching pitch set to 0.05 mm obtained the best result. The laser power and the laser scan speed were very important parameters for producing the nickel porous material. When the laser power was low and the laser scan speed was high, the porous material became brittle because of low input energy per unit area. When the laser power was high and the laser scan speed was low, the porous material had large porosity because of high input energy per unit area. Close relation between the laser power and the laser scan speed was observed. Optimum quantitative relation between the laser power and the laser scan speed produced the good nickel porous material.