Search

A series of patterned monolayer brazed cubic boron nitride (CBN) wheels were prepared to study the influence of arraying parameters on their dry grinding performance on hardened steel. The effect of grit spacing in grinding direction (X) and lateral direction (Z), grit size, and arraying angle on the grinding force, grinding temperature, and surface roughness was examined. Under a constant CBN grit density, varying the grit spacing in different directions and arraying angles had a minor influence on grinding forces and grinding temperature. However, the surface roughness decreased when the grit spacing X was increased and spacing Z was decreased. With the increase of grit spacing or a decrease of grit density, the grinding forces and the grinding temperature decreased, and the surface roughness increased. Use of larger grit size also increased grinding forces, grinding temperature, and surface roughness. At an arraying angle of 50°, the grinding force, grinding temperature, and surface roughness achieved minimum.

Hollow spherical corundum granules were introduced into a vitrified bond diamond grinding wheel as pore former. The influences of content and particle size of the hollow spherical corundum granules on porosity, flexural strength, and hardness of the vitrified bond diamond wheel samples were systematically investigated. The grinding performance of the designed vitrified bond diamond cup wheel on sapphire and 6H-silicon carbide (SiC) substrates was examined, and morphological properties of the ground surface were evaluated. Results showed that higher content and smaller size of hollow spherical corundum granules could lead to the increase of the porosity and the decrease of flexural strength and hardness. Sapphire and 6H-SiC substrates could be effectively ground by the vitrified bond diamond cup wheel containing 8% hollow spherical corundum granules. During the grinding, although a brittle mode dominated the material removal of two substrates, more ductile removals and lower surface roughness could be identified from 6H-SiC substrate than from sapphire.

A sponge-loaded Bi2WO6 catalyst was prepared through a facile physical load method by using sponge as the carrier and PVA as the immobilizing agent. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (FE-SEM), energy dispersive spectrometry (EDS) and element mapping. The results indicated that the addition of PVA did not impact the crystalline structure of Bi2WO6 and the Bi2WO6 catalyst had been successfully loaded to the sponge surfaces with the presence of PVA.The preparation conditions were optimized with the orthogonal experiment and confirmed by photocatalytic activity evaluation to be: 0.04 mmol PVA, the sponge-to-catalyst mass ratio of 1:1, the solid-to-liquid ratio of 8 g/L, and load temperature 100 °C. Under the optimum conditions, the average load rate of the photocatalysts was 43.24 % and the TCH photocatalytic degradation under visible light reached 94.00 %. Moreover, the sponge-loaded Bi2WO6 composite catalyst showed a stable photocatalytic activity under visible light irradiation.