Heller Industries Inc. | https://hellerindustries.com/wp-content/uploads/2022/06/Optimizing-Reflowed-Solder-TIM-sTIMs-Processes-for-Emerging-Heterogeneous.pdf
. The solubility of nickel in the indium is very low so diffusion-controlled growth of the intermetallic (IMC) layer is slow. On exposure to air, nickel forms a unsolderable oxide on its surface, so it is protected with a flash coating of gold. In
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