Cymcap Hot Crack -

Hot cracking (also known as solidification cracking) occurs in metallic alloys when thermally induced tensile strains exceed the material’s capacity for ductility during the final stages of solidification. In electronic packaging, hot cracks in termination materials like Cymcap lead to intermittent connections, increased equivalent series resistance (ESR), and premature field failures.

The term “Cymcap hot crack” has emerged in quality reports of high-voltage ceramic capacitors after lead-free reflow soldering (260°C peak). Cymcap is a Cu–Mn–Ni alloy (nominal composition: Cu–12Mn–3Ni–0.5Fe) chosen for its low coefficient of thermal expansion (CTE ≈ 16 ppm/K) and high electrical conductivity. However, field returns show characteristic intergranular cracks originating at the solder–Cymcap interface and propagating inward. cymcap hot crack

This paper systematically characterizes the hot cracking phenomenon, identifies root causes, and proposes alloy modifications and process controls. Hot cracking (also known as solidification cracking) occurs

DSC heating/cooling cycles (10°C/min) revealed: A wide freezing range (>150°C) is a known

A wide freezing range (>150°C) is a known susceptibility factor for hot cracking, as it promotes extended coherent dendrite networks with residual liquid films at grain boundaries.

To eliminate Cymcap hot crack, engineers employ a hierarchy of controls: