IYPT 2019 Elements 036: Krypton: Lighting, the metre, and nuclear facilities

Element 35 in our International Year of the Periodic Table series is krypton. Used in high-speed flash photography, krypton also has a link to the definition of the metre and can help detect covert nuclear facilities. One of krypton’s common everyday uses is in some types of photographic flashes, particularly those for high-speed photography. It’s also …

Effect of Heat Treatment on Tribological Properties of Ni-B Coatings on Low Carbon Steel: Wear Maps and Wear Mechanisms

Among the alternatives for using low-carbon steel in parts with heavy wear, as gears and bearing surfaces, Ni-B electroless coatings deposited on these steels are considered due to their wear resistance. Wear maps, elaborated from friction or wear results found for different evaluated conditions, are a very useful tool for the selection of materials based …

An Efficient Numerical Model of Elastohydrodynamic Lubrication for Transversely Isotropic Materials

An elastohydrodynamic lubrication model for a rigid ball in contact with a transversely isotropic half-space is constructed. Reynolds equation, film thickness equation, and load balance equation are solved using the finite difference method, where the surface vertical displacement or deformation of transversely isotropic half-space is considered through the film thickness equation. The numerical methods are …

Frictional Properties of a Nanocomposite Material With a Linear Polyimide Matrix and Tungsten Diselinide Nanoparticle Reinforcement

Frictional properties of a self-lubricating nanocomposite material with an A–OOO polyimide matrix reinforced by gas-phase synthesized tungsten diselenide (WSe2) nanoparticles are studied with a homemade low sliding speed tribometer. Tungsten diselenide is often used as a solid lubricant due to its layered structure yielding to anisotropy, which enhances lubrication properties. To facilitate molecular adhesion friction …

Friction and Damage Evolution of the Borided CoCrMo Alloy

In this study, friction and evolution of cohesive failures (cracks and spallations) in CoB/Co2B layers were analyzed. Thermochemical treatment was carried out at 950, 975, and 1000 °C during 6, 8, and 10 h of exposure time, respectively. The characterization techniques include scanning electron microscopy (SEM) for morphology inspection of layers and thickness measurement, X-ray …

Friction and Damage Evolution of the Borided CoCrMo Alloy

In this study, friction and evolution of cohesive failures (cracks and spallations) in CoB/Co2B layers were analyzed. Thermochemical treatment was carried out at 950, 975, and 1000 °C during 6, 8, and 10 h of exposure time, respectively. The characterization techniques include scanning electron microscopy (SEM) for morphology inspection of layers and thickness measurement, X-ray …