Wetting behavior and bonding characteristics of bismuth-based glass brazes used to join Li-Ti ferrite systems

Panpan Lin, Tiesong Lin, Peng He, Dusan P. Sekulic

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


A series of bismuth-based glass brazes were used to join Li-Ti ferrite. The wetting behavior and bonding characteristics of glass brazes utilized to join Li-Ti ferrite were systematically investigated. The glass brazes feature a good CTEs match, and a favorable wetting ability over Li-Ti ferrite mating surfaces. Upon brazing, the Bi-rich phases (Bi46Fe2O72, Bi12SiO2 and Bi24B2O39) and Zn-rich phase (ZnO) were observed in the Li-Ti ferrite/Bi40 and Li-Ti ferrite/Bi35 joints. The Zn2SiO4, ZnFe2O4 and Bi5Ti3FeO15 whiskers were detected in the Li-Ti ferrite/Bi25, Li-Ti ferrite/Bi20 and Li-Ti ferrite/Bi25-BC joints, respectively. No crystalline phase was detected in the Li-Ti ferrite/Bi30-BF joint. Multiple factors impact the joint strength, such as the three-point bending strength of glass brazes, the CTE match of the glass braze and the Li-Ti ferrite, as well as the crystal phases within the seam. The joint strength has the maximum value of 86 MPa for a Li-Ti ferrite/Bi25-Ba couples. The main impact is attributed to the strengthening effect of Bi5Ti3FeO15 whiskers. The dielectric properties of Li-Ti ferrite/glass braze joints show a stronger frequency dependence than that of Li-Ti ferrite at low frequency. This is attributed to the formation of new interfaces. The glass matrix or a crystal phase with a higher dielectric constant could counteract the decrease in the dielectric constant of heat-treated Li-Ti ferrite. Therefore, the dielectric constant of joint, especially that of Li-Ti ferrite/Bi25-BC joint, would be near that of the original Li-Ti ferrite at a high frequency. Meanwhile, no increase in the dielectric loss tangent of a joint takes place.

Original languageEnglish
Pages (from-to)13530-13540
Number of pages11
JournalCeramics International
Issue number16
StatePublished - Nov 2017

Bibliographical note

Funding Information:
This research is supported by “National Natural Science Foundation of China (NSFC, Grant number 51474081 and 51475103)” and “The Funds for Distinguished Young Scientists of Heilongjiang Province (Grant number JC2015011)”. One of the authors (DPS) acknowledges a support through the 1000 Foreign Expert Professor Plan.

Publisher Copyright:
© 2017


  • Bismuth-based glass
  • Dielectric constant
  • Dielectric loss tangent
  • Joint strength
  • Li-Ti ferrite
  • Microstructure
  • Wetting ability

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry


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