摘要： Dense Boron-doped diamond (BDD) composites were fabricated by high pressure and high-temperature sintering (HPHT) at 5 GPa and 1450 °C for 300 s in presence of Al, B and C as sintering additives. Phase compositions, microstructures, and electrochemical performances of sintered specimens were investigated by X-ray di?raction (XRD), scanning electron microscopy (SEM), and electrochemistry. Results suggested that Al3BC3 and Al4C were formed by in-situ reaction between sintering additives and diamond, which can promote densi?cation of BDD. In addition, BDD composites containing 10 wt% sintering additives exhibited the highest electrical resistivity (4.40 × 10?4 Ω m) and hole concentration (4.55 × 1025/m3). The working potential windows of BDD composite electrodes in 0.1 M H2SO4, 0.1 M Na2SO4 and 0.1 M NaOH electrolytes were estimated to 1.9 V, 2.9 V and 2.3 V, respectively. Electron transfer coe?cients of composite electrodes approached 0.5, con?rming good reversibility. Finally, methylene blue was completely degraded by BDD composite electrodes within 120 min using NaCl as supporting electrolyte.