Aluminum magnesium boride (BAM) and boron carbide (B4C) show great promise for engineering applications due to their high strength, hardness, impact resistance along with low mass density. Four BAM-B4C composite specimens (100% BAM, BAM + 10 wt% B4C, 20 50 B4C) produced by spark plasma sintering were characterized using electron microscopy energy dispersive spectroscopy. Mechanical properties s...

The effect of an electroless Ni-Cu-P coating on the fatigue behavior of quenched and tempered CK45 steel has been investigated. The fatigue tests under rotating bending conditions have been conducted in three different conditions of uncoated, as-deposited and shot peened prior to the coating deposition. The results indicate that plating of the base steel leads to a fatigue life reduction. The d...

Graphene can be synthesized from polyacrylonitrile (PAN) polymer through pyrolysis. A metal catalyst such as nickel (Ni) is required for the conversion of the polymer to graphene. The metal catalysts can be placed either atop or underneath the polymer precursor. We observed that spatially non-uniform and disconnected graphene was fabricated when PAN film coated with a Ni layer was pyrolyzed, re...

In order to improve the high temperature oxidation and ablation resistance of C/C composites, ZrB2-ZrC-SiC ultra-high composite ceramic coatings were prepared on composites by laser cladding using Zr, B4C, Si as raw materials. The microstructure coating was characterized scanning electron microscopy (SEM) X-ray diffraction (XRD). Air isothermal (1600 °C, 80 min) oxyacetylene flame (2400 kW/m2, ...

The ablation material used during the National Ignition Campaign, a glowdischarge polymer (GDP), does not couple as efficiently as simulations indicated to the multipleshock inducing radiation drive environment created by laser power profile [1]. We investigate the performance of two other ablators, boron carbide (B4C) and high-density carbon (HDC) and compare with GDP under the same hohlraum c...

In situ synthesized TiB2-reinforced TiAl composites usually possess high strength. However, it is very expensive to use B powder to synthesize TiB2 particles. Moreover, the strength enhancement of TiB2/TiAl composite is generally at the cost of plasticity. In this study, in situ dual reinforcement TiB2-Ti2AlC/TiAl composites were fabricated by using B4C powder as the B and C source, which great...

This thesis is a theoretical study of configurational disorder in icosahedral boronrich solids, in particular boron carbide, including also the development of a methodological framework for treating configurational disorder in such materials, namely superatom-special quasirandom structure (SA-SQS). In terms of its practical implementations, the SA-SQS method is demonstrated to be capable of eff...

Platinum is added to thermal barrier coatings (TBCs) as it is observed empirically to extend their lifetime, but the mechanism by which Pt acts is unknown. Since Pt has been proposed to alter diffusivities in NiAl, a key component of TBCs, we use first-principles quantum mechanics calculations to investigate atomic level diffusion mechanisms. Here, we examine the effect of Pt on five previously...

Electrocatalytic activity for the hydrogen evolution reaction on Ni–Co–LaNi5 composite electrodes prepared by electrochemical codeposition technique was evaluated. The relationship between the current density for hydrogen evolution reaction and the amount of LaNi5 particles in Ni–Co baths is like the well-known “volcano plot”. The Surface morphology and microstructure of Ni–Co–LaNi5 coatings we...

Metallic composite coatings with ceramic particles can be used to improve the mechanical and corrosion properties of steel. In the present research, Ni-ZrO2-TiO2 composite coating was fabricated on AISI 430 stainless steel through the electrodeposition method. The effect of the current density of electroplating (15, 17, 20, and 23 mA.cm-2)was investigated on the...