Impact of Ce2O3 on microstructure and properties of matrix-body for PDC drill bits synthesized via pressureless melt infiltration

• Published in: Ceramics international Vol. 48; no. 18; pp. 26945 - 26953
• Main Authors: Zhou, Xinjun, Zhang, Zhengfu, Li, Xiulan, Zhang, Xudong, Li, Yuxi, Chen, Manjiao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.09.2022
• Subjects: Ce2O3; Mechanical properties; Microstructure; Pressureless melt infiltration; Mechanical properties; Ce2O3; WC; Microstructure; Pressureless melt infiltration
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2022.06.006

The materials of matrix-body polycrystalline diamond composite (PDC) bits were fabricated through pressureless melt infiltration method at 1200 °C for 1 h within vacuum furnace using molten CuNi metallic binder, Ni and WC powders (including cast WC, spherical WC, and fine WC). Various weight ratios of Ce2O3/(WC + Ni + CuNi) ranging from 0 to 0.01 were added to matrix-body materials. The influence of Ce2O3 on the microstructure, phase formation, phase transformations, and related mechanical properties of matrix-body materials was thoroughly investigated. The results show that experimental temperature led to the decomposition of WC and partial dissolution of W and C in CuNi binder alloys. In matrix-body materials with no Ce2O3 addition, only new W2C phase was formed. With further increase in Ce2O3/(WC + Ni + CuNi) ratios, spherical WC was dispersed into smaller WC particles. Meanwhile, new phases (namely Ni2W4C, C, and W2C) were found. The material exhibited an optimal hardness (HRA = 93.7) and transverse rupture strength (1846.8 MPa) when Ce2O3/(WC + Ni + CuNi) ratio was 0.006. However, impact toughness was slightly decreased, while the highest value of 6.45 J cm−2 was measured for the sample with Ce2O3/(WC + Ni + CuNi) ratio of 0.01.