Surface modification of Ni3Al-based alloy IC6 with intense pulsed ion beams

The effects of intense pulsed ion beams (IPIB) irradiation (ions of C+ and H+, accelerating voltage V ¼ 250 kV, ion current density J ¼ 1002200 A/cm2, pulse duration t ¼ 60 ns, and pulse number n ¼ 12224) on the phase and microstructure response of Ni3Al-based alloy IC6 have been studied. It is shown that the deformation texture can be formed on the surface layer of target under IPIB irradiation with a low current density (100 A/cm2). With further increasing ion current density (150–200 A/cm2), the formation of amorphous and new phases occurs. A higher density of dislocations can be observed in the irradiated specimen compared to the unirradiated specimen

Visible-Light Photocatalytic Activity of S‑Doped α‑Bi₂O₃

A batch of S-doped α-Bi₂O₃ and pure α-Bi₂O₃ were prepared by a simple chemical preparation method using thiourea as sulfur source, and the S-doped α-Bi₂O₃ samples promoted the activity in the visible light range in terms of photocatalytic degradation of RhB. The photocatalysts were characterized by X-ray diffraction, scanning electron microscope, UV–vis diffuse reflectance spectrophotometer, X-ray photoelectron spectroscopy, and X-ray absorption near-edge structure. It is surprisingly found that the S atom substitutes on the Bi site rather than substituting on the O site. Further work on the first-principle calculations confirms the S substitution and reflects the differences of electronic structures between S-doped α-Bi₂O₃ and pure α-Bi₂O₃. The possible mechanism for the enhancement of visible-light photocatalysis by S doping is proposed in terms of both experimental results and calculations

Effect of intense pulsed ion beams irradiation on the oxidation behavior of γ′-based superalloy

Intense pulsed ion beams (IPIB) with three different power densities (25, 37.5 and 50 MW/cm2) are employed for the surface treatment of c0-based superalloy IC6. The influence of IPIBirradiation on the oxidation behavior of IC6 at 1100 C for up to 100 h is investigated. It is found that the phase states of IC6 are dramatically changed after IPIBirradiation and the oxidation behavior of the irradiated coupons depends greatly on the power density of IPIB. IPIB irradiation with a power density of 25 or 37.5 MW/cm2 significantly reduces the oxidation rate with respect to the unirradiated coupon. The improvement of the oxidation resistance can be attributed to a change in the oxidation products from a three-layered scale of Ni-rich oxides for the unirradiated coupon to a two-layered scale of Mo- and Al-rich oxides. In contrast, IPIBirradiation with a power density of 50 MW/cm2 proves to be detrimental, causing a higher oxidation rate. The oxidation mechanism for IPIBirradiated coupons is discussed

A study on microstructure and service property of Ni3Al base alloy irradiated by intense pulsed ion beams

A study on microstructure and service property of Ni3Al base alloy irradiated by intense pulsed ion beam

Bismuth Oxybromide with Reasonable Photocatalytic Reduction Activity under Visible Light

The original bismuth-based oxyhalide, known as the Sillén family, is an important photocatalyst due to its high photocatalytic oxidation activity. Here, we report a bismuth-based photocatalyst, Bi₂₄O₃₁Br₁₀, with reasonable reduction activity. The photoreduction capability of Bi₂₄O₃₁Br₁₀ in H₂ evolution from water reduction is 133.9 μmol after 40 h under visible light irradiation. Bi₂₄O₃₁Br₁₀ presents the highest activity among Bi₂O₃, BiOBr, and Bi₂₄O₃₁Br₁₀ in photocatalytic reduction of the Cr (VI) test, and Cr (VI) ions are totally removed in 40 min. The Mott–Schottky test shows the bottom of the conduction band fits the electric potential requirements for splitting water to H₂. First-principles calculations indicate the conduction band of Bi₂₄O₃₁Br₁₀ mainly consists of hybridized Bi 6p and Br 4s orbitals, which may contribute to the uplifting of the conduction band

Improving the Solubility of Mn and Suppressing the Oxygen Vacancy Density in Zn_0.98Mn_0.02O Nanocrystals via Octylamine Treatment

Zn_0.98Mn_0.02O nanocrystals were synthesized by the wet chemical route and were treated with different content of octylamine. The environment around Mn and the defect type and concentration were characterized by photoluminescence, Raman, X-ray photoelectron spectroscopy, and X-ray absorption fine structure. It is found that N codoping effectively enhances the solubility of Mn substituting Zn via reducing donor binding energy of impurity by the orbital hybridization between the N-acceptor and Mn-donor. On the other hand, the O atoms released from MnO₆ and the N ions from octylamine occupy the site of oxygen vacancies and result in reduction of the concentration of oxygen vacancies in Zn_0.98Mn_0.02O nanocrystals