Formation and growth of manganese phosphate passivation layers for NTC ceramics

Hsing-I Hsiang, Li Then Mei, Yi Hon Lin

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)723-728
Number of pages6
JournalJournal of Alloys and Compounds
Volume484
Issue number1-2
DOIs
Publication statusPublished - 2009 Sep 18

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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