Achieving isotropic thermal properties in graphite flake/Cu composites through the radial structural design of reinforcement

• Published in: Composites communications Vol. 50; p. 102026
• Main Authors: Song, Dian, Wang, Peichen, Zhou, Wuxing, Huang, Junchen, Lu, Fenfang, Zhang, Zhihao, Xiong, Degan, Liu, Qian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2024
• Subjects: Fast hot-pressing sintering; Graphite/copper composites; Isotropy; Radial structure; Structural design; Thermal properties; Graphite/copper composites; Thermal properties; Radial structure; Structural design; Isotropy; Fast hot-pressing sintering
• ISSN: 2452-2139
• DOI: 10.1016/j.coco.2024.102026

Conventional graphite flakes (GFs)/Cu composites suffer from severe anisotropy in terms of their thermal conductivity (TC) and coefficient of thermal expansion (CTE) between the in-plane and through-plane directions, which as thermal management materials (TMMs) play crucial roles in the overall heat dissipation performance of electronic components. To address this issue, a radial structural design for the reinforcement phase of GFs was developed. In this study, conventional stacked structured GFs/Cu composites and newly designed radial structured GFs/Cu composites were prepared by electroless plating of Cu on the surface of GFs followed by fast hot-pressing technology. The GFs content was varied from 30 to 70 vol%. The spatial orientation of the GFs was determined via X-ray computed tomography. For the radial structured GFs/Cu composites, the CTE were 11.52 and 14.42 ppm K−1 in the in-plane direction through-plane direction when the GFs content was 50 vol%, and the TC reached maximum values of 681 and 590 W m−1 K−1 in the in-plane direction and through-plane direction when the GFs content was 50 vol%. The TC in the through-plane direction was nine times greater than that of the stacked structured GFs/Cu composites (65 W m−1 K−1) at the same GFs content, demonstrating overall isotropy. Although radial structured GFs/Cu composites have more defects that can affect their thermal properties due to process factors, they have better heat dissipation abilities in practical applications; this indicates their great potential as a new generation of TMMs. •A novel radial structured graphite/Cu composites were designed and prepared.•Radial structural is designed to enhance isotropic composites' thermal properties.•Thermal conductivity of radial structured is 10 times higher than stake structured.•Radial structured graphite/Cu exhibits excellent thermal expansion properties.