Study on ultrasonic-assisted lapping performance and material removal behavior of diamond/SiC composites

Diamond/SiC composites have emerged as a new generation of highly promising materials for semiconductor packaging due to their excellent thermal conductivity. However, the exceptionally hard diamond and SiC phases in the composites have made precision machining a substantial difficulty. This study specifically explores the utilization of ultrasonic-assisted lapping (UAL) to enhance the machining performance of diamond/SiC composites. The focus is on investigating the effects of UAL on the material removals, including the brittle-ductile transition of sample interfacial diamond at different ultrasonic conditions, as well as the surface morphology of diamond/SiC composites. The removal mechanism of diamond/SiC composites under different machining conditions and the transient impact action of the abrasive were systematically analyzed, taking into account the abrasive size, the mechanical effects of ultrasonic vibration, and the interplay of processing parameters. The experimental results reveal that UAL significantly changes the traditional removal mode of diamond/SiC composites. At a constant rotational speed, the diamond abrasive size in the lapping solution exerts the primary influence on the sample surface morphology, followed by the average power of ultrasonic. Compared to conventional lapping methods, UAL improves the removal rate by 10.3 %, 5.4 %, and 5.3 % for abrasive sizes of 8 μm, 4 μm, and 1 μm, respectively. Optimally, the best surface quality finish of diamond/SiC composites was achieved with a lapping solution containing 4 μm abrasive particles and an average ultrasonic vibrator power of 75 W. This study underscores the potential of UAL to enhance the efficiency and quality of diamond/SiC composite machining.