Electroless Ni-P Deposition on an Al5052 Substrate for Thermal Management Applications

Thermal management in a heat source-based electronic package is a necessity for reliable, long-lasting performance, as it is compulsory to dissipate the generated heat effectively. In this study, a novel nickel–phosphorous (Ni–P) alloy coating on an aluminum substrate is proposed to obtain improved thermal properties such as thermal conductivity ( ${k}$ ), total thermal resistance ( ${R}_{{\mathrm {th-tot}}}$ ), and device junction temperature ( ${T}_{j}$ ). The performance of the electroless Ni–P coating is observed under different deposition times and test conditions. The morphology of Ni–P coating results in a cauliflower-like grown structure on a substrate with 91.2 wt% of Ni and 8.8 wt% of P. X-ray diffraction spectra indicate the presence of crystalline Ni (111) and (220) peaks and an average crystallite size of 541 nm. The thermal conductivity of the Ni–P coated substrate results in 14.42 W/mK, whereas bare Al results in 8.03 W/mK. The thermal transient measurement results in an impressive difference in both $\Delta {R}_{{\mathrm {th-tot}}}$ (6.31 K/W, 4.68 K/W) and $\Delta {T}_{j}$ (11.84 °C, 5.82 °C) under different test conditions. It is found that 0.33- $\mu \text{m}$ surface roughness with a 7.5- $\mu \text{m}$ coating thickness potentially improves the thermal behavior of Ni–P substrates, and it is believed that Ni–P is suitable for being used as an alternative coating option for electronic packages.