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采用化学镀技术在铁粉表面沉积Ni-P镀层,制备包覆型复合粉末。并用实验室制备的复合粉末烧结出孔隙率较为均匀的多孔材料。通过SEM、XRD、EDS等测试方法分析复合粉末的组织形貌、镀层形态和磷含量。由于非晶态在热力学上的不稳定性使其在烧结过程中发生晶化,通过研究其不同升温速率下的热分析曲线,计算粉末化学镀层的晶化激活能。对烧结过程的XRD分析表明:镀层在300℃时开始出现晶化,到400℃时晶化过程基本完成。在接近烧结温度(900℃)时,XRD谱图中出现了[Fe,Ni]和FeNi2P的衍射峰,间接说明了被包覆粉末与镀层之间发生了一定的互扩散。
Electroless plating technology is used to deposit Ni-P coating on the surface of iron powder to prepare coated composite powder. The porous materials with more uniform porosity were sintered by the laboratory prepared composite powders. The morphology, coating morphology and phosphorus content of the composite powders were analyzed by SEM, XRD and EDS. As amorphous state in the thermodynamic instability of the crystallization process occurs during sintering, through the study of different heating rate of the thermal analysis curve calculated powder coating chemical activation energy of crystallization. The XRD analysis of the sintering process showed that the coating began to crystallize at 300 ℃, and the crystallization process was basically completed at 400 ℃. The diffraction peaks of [Fe, Ni] and FeNi2P appeared in the XRD spectrum near the sintering temperature (900 ℃), which indirectly indicated that there was some interdiffusion between the coated powder and the coating.