Search

Lightweight ceramic proppants are prepared using coal gangue, fly ash, and bauxite as raw materials, and a mixture of manganese dioxide and magnesium oxide is used as composite additives. The total content of the coal gangue and fly ash in the raw materials reaches up to 70 wt%. The effects of coal gangue and fly ash precalcination, sintering temperature, and composite additive content on the phase compositions, microstructures, and performances of the resulting ceramic proppants are studied in detail. The ceramic proppant prepared at 1285 °C using 1 wt% of the composite additive is composed of quartz, corundum, and mullite. It also presents the desired sphericity, roundness, and microstructure. The apparent density, bulk density, and breakage ratio of the ceramic proppant described above are 2.55 ± 0.06 g/cm3, 1.03 ± 0.02 g/cm3, and 8.30 ± 0.68% at 35 MPa, respectively. This ceramic proppant belongs to lightweight ceramic proppants and meets the requirement of the 5K grade in the standards of SY/T 5108-2014 and API STD 19C-2018. [ABSTRACT FROM AUTHOR]

In this study, B 4 C–TiB 2 composite ceramics with different TiB 2 contents sintered via hot pressing are processed into ceramic tools to turn AISI 4340 workpieces. Finite element analysis using the Deform-3D software is conducted to examine the effects of the cutting speed, depth of cut, and feed rate on the main cutting force and tool temperature of the B 4 C–TiB 2 ceramic tools. The wear mechanism is investigated through the microstructural analysis of the wear profile obtained after the turning experiments. Simulation results show that the B 4 C–30%TiB 2 ceramic tool demonstrates the best cutting performance. The optimal cutting parameters for the B 4 C–30%TiB 2 ceramic tool are a cutting speed of 300 m/min, depth of cut of 0.3 mm, and feed rate of 0.1 mm/r. The turning experiments reveal that the B 4 C–30%TiB 2 ceramic tool has a longer tool life than a commercially available YD tungsten carbide tool. The main wear forms of the B 4 C–30%TiB 2 ceramic tool are craters, chipping, and flank wear, and the wear mechanism can be attributed mainly to abrasive wear, adhesive wear, oxidative wear, and diffusion wear. This work can lay a theoretical foundation for the practical application of B 4 C–TiB 2 ceramic tools. [ABSTRACT FROM AUTHOR]