The preparation method has a significant impact on the thermophysical properties of diamond/copper composites. Common preparation methods include the high-temperature, high-pressure (HTHP) method, liquid-phase infiltration, discharge plasma sintering, and vacuum hot-press sintering.
The high-temperature, high-pressure method melts copper powder into a copper melt at high temperatures and applies high pressure using a six-sided press to produce dense diamond/copper composites. This method yields composites with high density, high diamond volume fraction, and ultra-high thermal conductivity, and it features a short processing time and high efficiency. However, this method involves harsh processing conditions, high production costs, and is limited to small-scale fabrication.
The liquid-phase infiltration method involves preparing diamond particles into a preform with a certain degree of strength, after which molten copper is filled into the gaps between the diamond particles via capillary action or pressure. Upon cooling, a composite material is obtained. Unpressurized infiltration requires holding the composite at a temperature above the melting point of the matrix metal for an extended period to achieve infiltration through capillary action; however, this process requires good wettability between the reinforcing phase and the matrix, and it has low infiltration efficiency.