In this paper, the electric-discharge machining (EDM) of non-contact seal grooves was studied. Two types of material, namely: tungsten carbide and silicon carbide were tested by EDM due to their hard machining behaviors. The geometry of seal grooves is another reason why grinding or other precision machining processes cannot be applied. Four parameters of EDM processes were studied, namely: ele...

A new ceramic sintering approach employing plastic deformation as the dominant mechanism is proposed, at low temperature close to the onset point of grain growth and under high pressure. Based on this route, fully dense boron carbide without grain growth can be prepared at 1,675-1,700 °C and under pressure of (≥) 80 MPa in 5 minutes. The dense boron carbide shows excellent mechanical properties...

ni-hard4 white cast iron is excellent wear resistant material and has been widely used in wearaffected equipment operated under extreme conditions, such as in mineral processing, cement, copper and iron manufacturing. in this study the effect of titanium addition (1.2, 0.7 and 0.2 wt.%) to the ni-hard 4 cast iron with the nominal composition of si= 1.5%, mn=0.5%, c=3%, p=0.05%, s= 0.05%, mo= 0....

Catalyst-free growth of boron carbide nanowires is achieved by pyrolysis of diborane and methane at 650–750 -C and around 500 mTorr in a quartz tube furnace. Electron-diffraction analysis using a novel diffraction-scanning transmission electron microscopy (D-STEM) technique indicates that the crystalline nanowires are single-crystal orthorhombic boron carbide. TEM images show that the nanowires...

We have investigated the changes in the electronic structure of molecu larly adsorbed orthocarborane fi lms, as a function of Hg co-adsorption, using photoe mission. The interaction between Hg and molecular orthocarborane is weak and results in the formation of some small aggregates of Hg. This behavior is very different from alkali metals interaction with molecular carborane fi lms and the int...

Point defects in silicon carbide are rapidly becoming a platform of great interest for single-photon generation, quantum sensing, and quantum information science. Photonic crystal cavities (PCCs) can serve as an efficient light-matter interface both to augment the defect emission and to aid in studying the defects' properties. In this work, we fabricate 1D nanobeam PCCs in 4H-silicon carbide wi...

Whiskers of iron carbide encased in carbon shells have been prepared from iron(I1) phthalocyanine. Solid FePc is oxygenated and then thermally treated under H2 flow. With proper control of conditions, Fe3C free from metallic iron can be synthesized. The product was characterized with the help of Mossbauer effect spectroscopy, X-ray diffraction, X-ray absorption, and transmission electron micros...

To understand the origin of cleavage fracture which dominates in Fe Mn -Al-C alloys at a high phosphorus concentration, we performed first-principles study of the phosphorus effect on ideal cleavage energy and critical stress in -carbide, Fe3AlC, a precipitate in the austenitic alloys. We find that phosphorus has higher solubility in Fe3AlC than in -Fe and sharply reduces the cleavage character...

We analyze the early stage of the highly anisotropic silicon carbide oxidation behavior with reactive force field molecular dynamics simulations. The oxidation of a-, C,- m-, and Si-crystallographic faces is studied at typical industry-focused temperatures in the range from 900 to 1200 °C based on the time evolution of the oxidation mechanism. The oxide thicknesses and the growth rates are obta...

The growth of niobium carbide in austenite involves the diffusion of both niobium and carbon. These elements diffuse at very different rates. A model is presented for the overall transformation kinetics of niobium carbide precipitation in austenite that takes into account the multicomponent nature of the diffusion process while at the same time allows for the curvature of the transformation fro...