Investigation of the mechanical properties of lead-free Sn-58Bi solder alloy with cobalt addition through flux doping

IF 1.7 4区材料科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Soldering & Surface Mount Technology Pub Date : 2024-07-31 DOI:10.1108/ssmt-02-2024-0007

Lina Syazwana Kamaruzzaman, Yingxin Goh, Yi Chung Goh

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引用次数: 0

Abstract

Purpose

This study aims to investigate the effect of incorporating cobalt (Co) into Sn-58Bi alloy on its phase composition, tensile properties, hardness and thermal aging performances. The fracture morphologies of tensile-tested solders are also investigated to correlate the microstructural changes with tensile properties of the solder alloys. Then, the thermal aging performances of the solder alloys are investigated in terms of their intermetallic compound (IMC) layer morphology and thickness.

Design/methodology/approach

The Sn-58Bi and Sn-58Bi-xCo, where x = 1.0, 1.5 and 2.0 Wt.%, were prepared using the flux doping technique. X-ray diffraction (XRD) is used to study the phase composition of the solder alloys, whereas scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) are used to investigate the microstructure, fractography and compositions of the solders. Tensile properties such as ultimate tensile strength (UTS), Young’s modulus and elongation are tested using the tensile test, whereas the microhardness value is gained from the micro-Vickers hardness test. The morphology and thickness of the IMC layer at the solder’s joints are investigated by varying the thermally aging duration up to 56 days at 80°C.

Findings

XRD analysis shows the presence of Co₃Sn₂ phase and confirms that Co was successfully incorporated via the flux doping technique. The microstructure of all Sn-58Bi-xCo solders did not differ significantly from Sn-58Bi solders. Sn-58Bi-2.0Co solder exhibited optimum properties among all compositions, with the highest UTS (87.89 ± 2.55 MPa) at 0.01 s⁻¹ strain rate and the lowest IMC layer thickness at the interface after being thermally aged for 56 days (3.84 ± 0.67 µm).

Originality/value

The originality and value of this research lie in its novel exploration of the flux doping technique to introduce minor alloying of Co into Sn-58Bi solder alloys, providing new insights into enhancing the properties and performance of these solders. This new Sn-Bi-Co alloy has the potential to replace lead-containing solder alloy in low-temperature soldering.

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通过助焊剂掺杂添加钴的无铅 Sn-58Bi 焊料合金的机械性能研究

目的本研究旨在探讨在 Sn-58Bi 合金中加入钴（Co）对其相组成、拉伸性能、硬度和热老化性能的影响。此外，还研究了拉伸测试焊料的断口形态，以便将微观结构变化与焊料合金的拉伸性能联系起来。然后，从金属间化合物 (IMC) 层形态和厚度的角度研究了焊料合金的热老化性能。设计/方法/途径使用助焊剂掺杂技术制备了 Sn-58Bi 和 Sn-58Bi-xCo，其中 x = 1.0、1.5 和 2.0 Wt.%。X 射线衍射（XRD）用于研究焊料合金的相组成，而扫描电子显微镜（SEM）和能量色散 X 射线光谱（EDX）则用于研究焊料的微观结构、断口和组成。拉伸性能，如极限拉伸强度 (UTS)、杨氏模量和伸长率是通过拉伸试验测试的，而显微硬度值则是通过显微维氏硬度试验获得的。研究结果XRD 分析表明存在 Co3Sn2 相，并证实通过助焊剂掺杂技术成功掺入了钴。所有 Sn-58Bi-xCo 焊料的微观结构与 Sn-58Bi 焊料没有明显差异。在所有成分中，Sn-58Bi-2.0Co 焊料表现出最佳性能，在 0.01 s-1 应变速率下 UTS 最高（87.89 ± 2.55 MPa），热老化 56 天后界面 IMC 层厚度最低（3.84 ± 0.67 µm）。这种新型锡-铋-钴合金有望在低温焊接中取代含铅焊料合金。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Soldering & Surface Mount Technology 工程技术-材料科学：综合

CiteScore

4.10

自引率

15.00%

发文量

审稿时长

>12 weeks

期刊介绍： Soldering & Surface Mount Technology seeks to make an important contribution to the advancement of research and application within the technical body of knowledge and expertise in this vital area. Soldering & Surface Mount Technology compliments its sister publications; Circuit World and Microelectronics International. The journal covers all aspects of SMT from alloys, pastes and fluxes, to reliability and environmental effects, and is currently providing an important dissemination route for new knowledge on lead-free solders and processes. The journal comprises a multidisciplinary study of the key materials and technologies used to assemble state of the art functional electronic devices. The key focus is on assembling devices and interconnecting components via soldering, whilst also embracing a broad range of related approaches.