CREATION OF MOLYBDENUM-COPPER COMPOSITES USING THE SPARK PLASMA SINTERING METHOD AND THE STUDY OF THEIR CHARACTERISTIC

At the moment, the issues related to the assurance of highly efficient thermal control in electronic systems continue to be relevant. More than half of the failure cases in the operation of electronic systems are caused precisely by the elevated temperature in the contact areas of their elements. Semiconductor components are installed on various plates or substrates that serve as elements of heat removal and provide effective thermal control. However, the selection of materials for such plates is a difficult task. Using the spark plasma method, the authors produced 3-D samples based on molybdenum and copper powders. The combination of copper with high thermal conductivity and molybdenum with a low-temperature coefficient of expansion makes it possible to use these metals as elements of heat removal for semiconductor components. According to the results of X-ray phase analysis, the authors identified that the composites, in addition to the main crystalline phases of molybdenum and copper, contain molybdenum carbide and molybdenum oxide. The presence of these chemical compounds is caused by the nature of the sintering process in graphite molds and the quality of raw materials. The authors identified that the dependence of the composites void density on the sintering temperature has a complex behavior related to the interchange of solid-phase and liquid-phase sintering. Scanning electron microscopy of samples showed that copper in samples fills in the intergranular space of molybdenum particles, and thus assure high density of end bulk products. In this case, sintering at a temperature of more than 1060 °C causes the runout of molten copper out of molds space that facilitates the formation of large pores with further sample density reduction. The study identified that, at sintering temperature of 1060 °C, the minimal number of pores appear in a sample, and the particles fit most closely to each other.

copper, molybdenum, spark plasma sintering, composite, microstructure