This study examines the effect of additives in manganese phosphating (MPO) solution on the formation of phosphate coating and the formation and growth mechanism of phosphates on NTC ceramics using X-ray diffractometry (XRD), scanning electron microscopy (SEM), and electron probe microanalyzer (EPMA). The results showed that addition of Zn2+ in MPO solutions can make the coating coverage more complete compared to Fe3+. In addition, manganese phosphate precipitation initiated near the grain boundary of Ni-rich region, is generated due to the preferential etching of Mn compared to Ni and Co. The passivation layer formed with manganese phosphate coating has good acid resistance and can act as a passivation layer for NTC during electroplating.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry