A Review of Binderless Polycrystalline Diamonds: Focus on the High-Pressure-High-Temperature Sintering Process

Natural diamonds have long been valued for their mechanical and optical properties. Over the last century, synthetic diamond fabrication has advanced through various methods. One dominant approach is the high-pressure-high-temperature (HP-HT) process, used to produce diamond compacts for industrial tools. However, these compacts often include a metallic binder, which can degrade performance. Recent efforts have shifted toward binderless diamond compacts, which offer superior properties. Despite progress, the sintering conditions remain too extreme for widespread industrial use. This gap motivated further research into optimizing P-T parameters. No prior work had resolved the industrial scalability of binderless diamonds. Understanding the synthesis process is crucial for advancing materials science.

This review aims to evaluate the HP-HT process for binderless diamond synthesis. The specific problem is the industrial infeasibility of current sintering conditions. The motivation lies in the potential of binderless diamonds to outperform traditional compacts and natural crystals. By comparing experimental techniques, the study seeks to identify viable pathways for industrial adoption. The focus is on P-T conditions and resulting properties of binderless diamonds. The goal is to highlight the current state of research and remaining challenges. This work provides a synthesis of findings from the literature. It addresses the need for scalable, high-performance diamond materials.

The study reviews natural diamond formation and experimental techniques for diamond synthesis. It focuses on HP-HT sintering methods used for binderless diamonds. The review approach includes comparing P-T conditions across different studies. Data is synthesized from literature on diamond powder sintering and compact fabrication. The authors analyze the mechanical and optical properties of binderless diamonds. They compare these properties with those of binder-containing and natural single-crystal diamonds. The review also addresses the industrial transfer potential of these materials. The approach emphasizes identifying gaps in current research and future directions.

Binderless diamond compacts exhibit mechanical and optical properties equal to or exceeding natural single-crystal diamonds. These properties surpass those of traditional binder-containing compacts. The sintering process requires high P-T conditions, limiting industrial feasibility. The review highlights the exceptional hardness and transparency of binderless diamonds. It reports that sintering temperatures often exceed 2000°C and pressures exceed 5 GPa. These conditions are not yet optimized for mass production. The study finds that binderless diamonds have fewer defects than their binder-containing counterparts. The results suggest that further optimization of P-T parameters is essential for industrial adoption.

The review concludes that binderless diamonds offer significant advantages over traditional compacts. Their mechanical and optical properties are comparable to natural single-crystal diamonds. However, the current sintering conditions remain too extreme for industrial use. The authors propose that optimizing P-T parameters is the next critical step. They suggest that further research is needed to reduce energy and pressure requirements. The review does not claim that binderless diamonds are already commercially viable. It emphasizes the need for scalable synthesis methods. The authors suggest that binderless diamonds could revolutionize industrial cutting and drilling applications.