Diamond-like carbon sintered compacts formed by spark plasma sintering

Abstract

A spark plasma sintering (SPS) method was utilized for the novel production of diamond-like carbon (DLC) compacts. Two amorphous carbon powders with different particle sizes (45μm and 24nm diameter) were employed as starting materials for the sintering experiments. The carbon powders were sintered using a SPS system at various sintering temperatures and holding times. The structural properties of the sintered compacts were evaluated using X-ray diffraction (XRD) analysis and high-resolution transmission electron microscopy (HRTEM). Disk-shaped compacts were obtained by sintering the powder with a particle diameter of 45μm, although the compacts were very brittle and easily broken. However, sintering of the 24nm diameter powder particles at temperatures of 1473 to 1573K with a holding time of 300s led to the successful production of sintered compacts without breakage. Reflection peaks related to graphite structure were observed in XRD patterns of the compacts sintered from the 24nm diameter particles. HRTEM analysis revealed that the compacts sintered at 1473K with a holding time of 300s had an amorphous structure and consisted of 34% sp3 carbon bonding. Evaluation of the structural properties indicated that sintered compacts with DLC structure could be created by the SPS method with 24nm diameter amorphous carbon particles.