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

采用激光烧结的方法制备了镍多孔材料。以连续模式下最大功率为100 W的CO_2激光器为热源，以镍粉为原料。镍粉的平均粒径为2.9 ~ 3.6 μm。研究了激光功率、激光扫描速度、光束离焦和孵化间距等工艺参数对镍粉激光烧结的影响。在氩气气氛中，用激光束照射镍粉制备镍多孔材料。制备的多孔镍材料随着光束离焦的增加而变脆。激光束刚好聚焦在粉末表面，就产生了良好的多孔材料。随着孵化节距的增加，镍多孔材料也变脆。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多孔镍材料的重要参数。当激光功率较低，激光扫描速度较高时，由于单位面积输入能量较低，多孔材料易碎。当激光功率高、激光扫描速度低时，由于单位面积输入能量大，多孔材料孔隙率大。激光功率与激光扫描速度密切相关。激光功率与激光扫描速度之间的最佳定量关系可制备出性能优良的镍多孔材料。

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.