Near Surface Changes Due to 700 keV Si⁺ Irradiation of Titanium Silicon Carbide

Abstract

The radiation damage response of Ti 3 SiC 2 heated from 120°C to 850°C during 700 keV Si + irradiation has been investigated. The samples were analyzed using glancing incidence Xray diffraction, Rutherford backscattering spectrometry, Raman spectroscopy, and scanning electron microscopy. For the sample at 120°C, irradiation results in a buildup of a heterogeneous surface and the formation of TiC x . Irradiation at 200°C results in maximum microstrain, a maximum in the c lattice parameter, and the appearance of a b phase in addition to the normal a phase of Ti 3 SiC 2. A minimum in the observed damage level near the surface was seen for irradiation at a sample temperature of 300°C but the damaged phase increases at higher temperatures. Differences between the present work and a previous C irradiation study have been ascribed to the enhanced Si defect transport at low temperatures.

Structural changes of Ti3SiC2 induced by helium irradiation with different doses

“…As calculated before [10,27], the Si atoms in Ti3SiC2 MAX phase materials have the lowest migration energy leading to high mobility and the Si layers were strongly disordered while the TiC layers remained mostly unperturbed after irradiation. The broadening of the peaks caused by He irradiation is much larger than that caused by other ions [23,28] at nearly the same irradiation dose.…”

“…More than 60% of the Ti3SiC2 phase transforms into damaged TiC at 0.2° and 0.4° while the remainder is the damaged Ti3SiC2 phase (about 20%) and less than 10% Ti3SiC2 phase. The formation of nano-scale TiC phase is largely attributed to collision cascade effects as described in our previous publications [23,28], where TiCx generation is linked to the loss of Si from irradiated Ti3SiC2 followed by the collapse of the Ti3C2 layers to form a defected TiCx phase. However, the generation of the equivalent amount of decomposed phase TiCx at much lower He damage dose compared to other ions Si + or C + suggests that: (1) the collapse of Ti3SiC2 as a result of the collision is not the sole reason of TiCx formation; (2) the helium existence prompting the displacement of Si atoms to the sinks such as voids, surface and grain boundaries is possibly another important reason.…”

Formation of Mo–Polydopamine Hollow Spheres and Their Conversions to MoO2/C and Mo2C/C for Efficient Electrochemical Energy Storage and Catalyst

“…Molybdenum‐based materials, with variable valence conditions (Mo 6+ , Mo 4+ , and Mo 2+ ), can form a variety of compounds, such as molybdenum dioxide (MoO 2 ), molybdenum trioxide (MoO 3 ) molybdenum disulfide (MoS 2 ), molybdenum phosphide (MoP), and molybdenum carbide (Mo 2 C), which have shown promise for energy storage and conversion . In these materials, MoO 2 is a promising anode material for lithium‐ion batteries (LIBs), which exhibits relatively high electrical conductivity, high reversible capacity (838 mAh g −1 ), and high electrochemical activity toward lithium .…”

Recent Progress on Molybdenum Oxides for Rechargeable Batteries

“…[6][7][8] Thus, the formationo fn ovel materials at the nanoscale level considerably enhancer echargeableb atteries with ah igh specific capacity,g ood rate capability,a nd long life. [25] Importantly,m olybdenumo xides, including MoO 3 and MoO 2 ,a re considered to be exceptional electrode materials for rechargeable batteries because of their low cost, chemical stability,h igh theoretical specific capacity (1117a nd 838 mAh g À1 for MoO 3 and MoO 2 ,r espectively), and environmentally friendly nature. For the past few decades, much research has been dedicated to the synthesis of nanostructured materials as electrodes for LIBs, SIBs, and other novel batteries.…”

“…[18] Amonge xisting materials, ad iversev ariety of molybdenum-based materials, such as MoS 2 , [19] MoO 2 , [20,21] MoO 3 , [22] Mo 2 C, [23] and MoP, [24] have been developed with inconstant valence conditions due to the variousv alence states of Mo, such as Mo 6 + ,M o 4 + ,a nd Mo 2 + .T hese composites are known as favorable materials for energys torage due to multielectron transfer during the reaction. [25] Importantly,m olybdenumo xides, including MoO 3 and MoO 2 ,a re considered to be exceptional electrode materials for rechargeable batteries because of their low cost, chemical stability,h igh theoretical specific capacity (1117a nd 838 mAh g À1 for MoO 3 and MoO 2 ,r espectively), and environmentally friendly nature. [26,27] To date, developments in currentM oO 3 -based batteries are limited by the low coulombic efficiency in the initial cycles, unstable cycling properties, low rate capability because of the irreversible conversion mechanism,l ack of structural sta-Diminishing fossil-fuelr esources and ar ise in energy demands has required the pursuit of sustainable and rechargeable energy-storagem aterials, including batteries and supercapacitors, the electrochemical properties of which dependl argely on the electrode materials.…”