The coefficients of thermal expansion (CTE) and thermal conductivity (TC) are important for heat sink applications, as they can minimize stress between heat sink substrates and chips and prevent failure from thermal accumulation in electronics. We investigated the interface behavior and manufacturing of diamond/Cu composites and found that they have much lower TCs than copper due to their low densities. Most defects, such as cavities, form around diamond particles, substantially decreasing the high TC of diamond reinforcements. However, the measurement results for the Cu-coated diamond/Cu composites are unsatisfactory because the nanosized copper layer on the diamond surface grew and spheroidized at elevated sintering temperatures. Realizing ideal interfacial bonding between a copper matrix and diamond particles is difficult. The TC of the 40 vol.% Ti-coated diamond/Cu composite is 475.01 W m⁻¹ K⁻¹, much higher than that of diamond/Cu and Cu-coated diamond/Cu composites under equivalent manufacturing conditions. The minimally grown titanium layer retained its nanosized and was consistent with the sintering temperature. Depositing a nanosized titanium layer on a diamond surface will strengthen interfacial bonding through interface reactions among the copper matrix, nanosized titanium layer and diamond particles, reducing the interfacial thermal resistance and exploiting the high TC of diamond particles, even if defects from powder metallurgy remain. These results provide an important experimental and theoretical basis for manufacturing diamond/Cu composites for heat sink applications.

中文翻译：

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金刚石/铜复合纳米涂层金刚石在散热器中的界面和制备工艺

热膨胀系数（CTE）和导热系数（TC）对于散热器应用非常重要，因为它们可以最大程度地减小散热器基板和芯片之间的应力，并防止电子设备中因热累积而导致的故障。我们研究了金刚石/铜复合材料的界面行为和制造，发现由于其密度低，它们的TC比铜低得多。大多数缺陷（例如腔）都在金刚石颗粒周围形成，从而大大降低了金刚石增强材料的高TC。然而，由于在升高的烧结温度下金刚石表面上的纳米尺寸的铜层生长并球化，因此用于铜涂覆的金刚石/铜复合材料的测量结果不能令人满意。很难在铜基体和金刚石颗粒之间实现理想的界面结合。40卷的TC。^-1 K ^-1，比同等制造条件下的金刚石/铜和镀铜的金刚石/铜复合材料要高得多。最小生长的​​钛层保持其纳米尺寸，并且与烧结温度一致。即使存在粉末冶金缺陷，通过在铜基体，纳米钛层和金刚石颗粒之间进行界面反应，在金刚石表面沉积纳米尺寸的钛层将增强界面结合，降低界面的耐热性并利用金刚石的高TC。这些结果为制造用于散热器的金刚石/铜复合材料提供了重要的实验和理论基础。