Journal of Materials Science

, Volume 50, Issue 20, pp 6559–6566 | Cite as

Investigation on sol–gel Al2O3 and hybrid phosphate-alumina insulation coatings for FeSiAl soft magnetic composites

  • Dong Liu
  • Chen WuEmail author
  • Mi YanEmail author
Original Paper


Alumina has been prepared by sol–gel method as the coating layer in the fabrication of FeSiAl soft magnetic composites (SMCs). Influence of the Al2O3 content on the magnetic properties of the SMCs has been studied, and optimized effective permeability (μ e = 116.3) and core loss (P cv = 331.2 mW cm−3) measured at 50 kHz, 100 mT was achieved with 0.8 wt% Al2O3. Hybrid phosphate-alumina coating has also been used to prepare the FeSiAl SMCs with a total addition of 0.8 wt%. Significantly improved performance of the SMCs can be achieved with the hybrid coating compared to single phosphate or alumina coating. The addition of 0.2 wt% H3PO4 and 0.6 wt% Al2O3 gives rise to the optimal magnetic properties (μ e = 123.4; P cv = 226.4 mW cm−3) of the FeSiAl SMCs. For the hybrid coating, the inner phosphate layer grown by direction reaction at the powder surfaces gives rise to excellent adhesion. Also, investigation on the thermal stability of the coatings indicates that the outer Al2O3 layer hinders the decomposition of the phosphate layer, leading to enhanced magnetic performance of the SMCs.


Al2O3 Coating Layer Effective Permeability Core Loss Hybrid Coating 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This work was supported by the Fundamental Research Funds for the Central Universities (2014QNA4007), Program for Innovative Research Team in University of Ministry of Education of China (IRT13R54), the Key Innovation Team of Magnetic Materials, and the Key Laboratory of Novel Materials for Information Technology of Zhejiang Province.

Compliance with Ethical Standard

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Key Laboratory of Novel Materials for Information Technology of Zhejiang ProvinceZhejiang UniversityHangzhouChina

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