Nanotechnologies / Materials
Electronic decive, Vehicle, Aerospace

Lead-free solders reinforced with ceramic particles
Joining and Welding Research Institute
Professor Hiroshi Nishikawa
https://researchmap.jp/read0191232?lang=en

This study aims to develop a solder alloy with high strength-ductility, and to obtain high reliability of solder joints. To improve thestrength and ductility synergistically, the design concept of multi-scale hybrid reinforcement with ceramic particles has been proposed. In addition, a new surface modification method for ceramicparticles, the ball milling-pyrolysis method, has been originally proposed in my research group. The surface modification of ceramicparticles, preparation of the composite solder alloy, the interface
regulation between the reinforcements and solder matrix, and themechanical property of composite solder alloys were systematically investigated. This research is expected to provide theoreticaland experimental basis for the development of high strength-ductility lead-free solder alloys.

▍ Background & Results▍ Significance of the research and Future perspective
As one way of establishing solder alloys with excellent properties and solder joints with high reliability, a new method of adding
non-reactive ceramic particles into solder alloys has been proposed. In particular, the research on surface modification methods
was undertaken to improve dispersibility of ceramic particles into
solder alloys. The findings obtained in this research can be applied
to improve the mechanical properties and reliability of various leadfree solder alloys, including not only Sn-Ag-Cu solder alloys but
also low-melting-point Sn-Bi solder alloys and etc.

Ceramic particles covered by nickel oxide

Solidification microstructure of solder alloy withceramic particles covered by nickel oxide

Elongation (%)

The expanding of electronic products into various new fields,such as the mobility and healthcare fields, requires better properties and reliability for the solder joints on electronic circuit boards.
In order to improve the mechanical properties and reliability oflead-free solder alloys, a new concept and method of adding ceramic particles to achieve both strength and ductility has been proposed, and a prototype of lead-free solder alloys reinforced withceramic particles was produced, and the mechanical property ofcomposite solder alloys were evaluated. The results obtained aredescribed in detail below.
英語版用
1. A new surface modification method, ball milling-pyrolysis method,
was proposed. The proposed method was successfully applied
to the surface modification of ceramic particles. In addition, themodification mechanism between NiO and ceramic particle wasexplored using in-situ transmission electron microscopy (TEM).
2. Reinforced Sn1.0Ag0.5Cu solder alloy was prepared with ultrasonic stirring and the microstructure evolution and refinement mechanism of reinforced solder alloys were systematically confirmed.
The modified ceramic particles could act as the nuclear sites. Inaddition, the melting behavior of the alloys were also confirmed.
3. The ultimate tensile strength and elongation of reinforced solder alloy could be improved synergistically. The ultimate tensile
strength was 35.9 MPa and the elongation was 31.4%, which werehigher than those of conventional Sn-3.0Ag-0.5Cu solder alloy.

Ultimate tensile strength (MPa)

Nanotechnologies / Materials

Abstract

Contents of micron-size particle into hybrid ceramic particles (mass%)
Mechanical properties of composite solder alloys reinforced
with hybrid ceramic particles

Mechanical properties of composite solder alloys reinforced with hybrid ce

P a t e n t
Huo, Fupeng; Shen, Yu-An, He, Siliang et al. Fabrication of NiO/ZrO2 nanocomposites using ball milling-pyrolysis method. Vacuum. 2021, 191, 110370.
doi: 10.1016/j.vacuum.2021.110370
Huo, Fupeng; Jin, Zhi; Han, Duy Le et al. Interface design and the strengthening-ductility behavior of tetra-needle-like ZnO whisker reinforced
T r e a t i s e Sn1.0Ag0.5Cu composite solders prepared with ultrasonic agitation. Materials & Design. 2021, 210 (15), 110038.
doi: 10.1016/j.matdes.2021.110038
Huo, Fupeng; Jin, Zhi; Han, Duy Le et al. Novel interface regulation of Sn1.0Ag0.5Cu composite solders reinforced with modified ZrO2: Microstructure
and mechanical properties. Journal of Materials Science & Technology. 2022, 125 (20), 157-170. doi: 10.1016/j.jmst.2022.01.040
URL
K e y w o r d lead-free solder alloy, surface modification of ceramic particles, mechanical property improvement