Combining Cr pre-coating and Cr alloying to improve the thermal conductivity of diamond particles reinforced Cu matrix composites

• Published in: Journal of alloys and compounds 2018-06, Vol.749, p.1098-1105
• Main Authors: Wang, Luhua, Li, Jianwei, Che, Zifan, Wang, Xitao, Zhang, Hailong, Wang, Jinguo, Kim, Moon J.
• Format: Article
• Language: English
• Subjects: Alloying; Bonding strength; Carbides; Chromium; Coating; Composite materials; Copper; Copper base alloys; Crystallography; Diamond films; Diamonds; Gas pressure; Graphite; Heat conductivity; Heat transfer; Infiltration; Interfacial structure; Metal matrix composites; Metal matrix composites (MMCs); Particulate composites; Scanning transmission electron microscopy; Thermal conductivity; Thickness; Transmission electron microscopy; Tungsten
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.03.241

Weak interface bonding inhibits high thermal conductive potential of diamonds in metal matrix composites reinforced with diamond particles (Cu/diamond composites). With an attempt to modify the Cu/diamond interface, we combine Cr pre-coating and Cr alloying to produce Cu-Cr/Cr-diamond composites by gas pressure infiltration. High resolution transmission electron microscopy (HRTEM) results reveal that Cr pre-coating on the diamond surface before infiltration promotes the formation of highly active graphite-like structures. These structures enhance the interfacial reaction and intensify the formation of a uniform and dense carbide layer on the diamond surface. By altering the Cr concentration in the Cu-Cr alloy matrix, the thickness of interfacial carbide layer is tailored. As a result, a maximum thermal conductivity of 810 W m-1 K-1 is achieved in the Cu-0.5 wt%Cr/Cr-diamond composite, which is the highest value among Cr-modified Cu/diamond composites reported so far. The high thermal conductivity is attributed to optimal interface conditions: moderate thickness of interfacial carbide layer, uniform and dense carbide layer on the diamond surface, and crystallographically aligned interfacial graphite layers. This study offers a new route to modifying interface bonding and to enhancing thermal conductivity of Cu/diamond composites. [Display omitted] •The Cu-Cr/Cr-diamond composites are prepared by gas pressure infiltration.•Highly active graphite-like structures promote the formation of interfacial carbide layer.•A high thermal conductivity of 810 W m-1 K-1 is achieved in the Cu-0.5 wt%Cr/Cr-diamond composite.