Dec 30, 2011 
Key Factors in the Selection of Lead-Free Solders
Nihon Superior Co., Ltd., a supplier of advanced soldering materials to the global market, announces that it will issue a new series of guides on “Key Factors in the Selection of Lead-Free Solders.” This series is intended to address the challenges in choosing a reliable lead-free solder. The first guide in the series is titled “Reliability of Lead-Free Solder in Thermal Cycling.”
Solder is used to connect electrical components to printed circuit boards to make functioning electronic devices. Recently, there has been a significant increase in interest in eco-friendly hybrid and/or electric vehicles that can be exposed to extreme temperatures during service. Therefore, resistance of a solder joint to thermal fatigue is an important characteristic.
Cross-Sections Provide an Answer
From the cross-sections below it is clear that in thermal cycling there are significant differences between the SN100C (Sn-0.7Cu-0.05Ni+Ge) and the Sn-3.8Ag-0.7Cu alloy. Cracks started to appear in the latter alloy after 2000 cycles with compete failure at by 4000 cycles. In the joints made with SN100C, there was no significant cracking until 4000 cycles. The conclusion is that SN100C has excellent resistance to thermal fatigue.
Nihon Superior is proud to present the case for implementing lead-free soldering at lower cost and higher reliability with its silver-free SN100C.
Comparison of the Incidence of Failure in a Surface Mount device
Test Conditions
Thermal Cycling：-45°C 15 min dwell/+125°C 25 min dwell
Board：FR-4 Immersion tin finish
SN100C-Reliable Joints
Long Service Life under Conditions of Thermal Cycling
http://www.nihonsuperior.co.jp/english/sn100c/pdf/040106_1_heatcycle.pdf
Nihon Superior was founded in 1966 when it began marketing unique flux products imported from the US. The company made its mark on society by gathering the most advanced soldering and brazing technologies and products from around the world, and supplying them to companies in the metal-joining industry. A turning point for the company came when it started developing its own soldering materials and with the success of its unique SN100C lead-free solder alloy Nihon Superior has become a major player in the global market. To support the growing demand for its products, Nihon Superior has established manufacturing and sales centers in Japan, China and other Asian countries, and the United States, and formed business partnerships with companies in other markets.
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