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With the widespread use of nuclear energy, the storage of surplus spent fuel has emerged as a critical issue that needs to be solved, especially for the efficient absorption of neutron radiation and secondary γ-rays generated by spent fuel produced when 10B absorbs neutrons. In this work, B4C/Al and W/B4C/Al coating were prepared on 316 L stainless steel by cold spraying. The microstructure and tensile properties of the coatings were investigated. The performance of the thermal neutron and secondary γ-rays absorption of the two coatings were simulated using the Monte Carlo approach. The results indicated that, compared to the B4C/Al coating, the W/B4C/Al coating exhibited better mechanical properties due to the tamping effect of the W particles. In addition, the secondary γ-rays absorption property was improved due to the addition of W. [ABSTRACT FROM AUTHOR]

Cold spray is a rapidly developing solid-state deposition technology in recent years. It has the characteristics of low spraying temperature and high velocity of spraying particles, hence showing a good prospect for preparing metal matrix composite (MMC) coatings and bulk materials. In particular, aluminum matrix composites have received great attention in electronics, aerospace and automobile industries due to their excellent physical and mechanical properties. In this paper, the research progress of cold-sprayed aluminum matrix composite coatings and materials was systematically introduced. Firstly, state of the art on cold sprayed coatings and materials with different reinforcing phases was presented. Then, research progress on different post-spray treatments, to improve the properties of as-sprayed deposit, was briefly discussed. Finally, the application fields and problems of cold-sprayed aluminum matrix composite coatings and materials were summarized. [ABSTRACT FROM AUTHOR]

Due to the high strength of the nickel‑aluminum bronze (NAB), the cold spray deposition efficiency of the NAB powders was less than satisfactory. To improve the deformation behavior of powder, different heat treatment strategies were adopted for gas atomized NAB powders and then the heat-treated powders were deposited on NAB substrates using a high-pressure cold spray system. For various powders and their corresponding deposits, a series of related characterizations were performed. The results indicate that the microstructure of the gas-atomized powder was mainly composed of martensitic β′ and bainite α with high hardness, resulting in low deposition efficiency and poor bonding between particles and particles in the prepared deposits. An effective technique of heat treatment can eliminate the non-equilibrium structure in the gas atomized powder, reduce the hardness of the powder, and significantly improve the deposition efficiency and enhance particle interface bonding. • Nickel‑aluminum bronze(NAB) powders using for cold spray were heat-treated. • The effects of heat treatment on microstructure of NAB powders were studied. • Heat treatment can eliminate NAB powder's non-equilibrium microstructure. • Powder heat treatment can improve deposition efficiency and particle bonding. [ABSTRACT FROM AUTHOR]

To improve the wear resistance of commercial AZ31 Mg alloy, two types of dense and thick composite coatings were prepared on AZ31 Mg alloy by means of cold-spray technology. For this purpose, Al 2 O 3 particles with different morphology (round and irregular) were separately added to the Al 5Si feedstock. The morphological effects of Al 2 O 3 on the microstructure, adhesion strength, hardness, and tribological properties of the coatings were comprehensively studied. Microstructural features of the coatings were examined by means of optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD). The analysis reveals that most of the grains in both coatings are ultrafine, and approximately half of the total grain boundary length is composed of low-angle grain boundaries. Wear, hardness, and pull-off tests showed that both types of Al 2 O 3 particles have a positive impact on porosity, adhesion, hardness, and wear resistance of the composite coatings. Compared to round Al 2 O 3 , irregular Al 2 O 3 particles exhibit better retention in the coating, thereby resulting in a higher hardness and wear resistance. • Al-5Si/Al 2 O 3 composite coatings were deposited on AZ31 Mg by cold spray. • The effects of Al 2 O 3 morphology on the coating were studied. • Irregular Al 2 O 3 particles exhibit better retention in the coating. • Irregular Al 2 O 3 particles can better increase coating's wear resistance. [ABSTRACT FROM AUTHOR]

Due to its low process temperature, cold spray (CS) is considered an excellent metallization method to deposit thick coatings on temperature-sensitive polymeric materials. However, in previous studies, the properties (such as electrical conductivity and adhesion strength) of the cold sprayed metallic coating on the polymeric substrate are relatively low. To address this issue, large-sized spherical Al 2 O 3 particles were added into Al powder in different proportions (i.e. 0, 10, 20, 30, 40 wt%) to prepare dense Al-Al 2 O 3 coatings on PEEK by CS. The effect of Al 2 O 3 content on microstructure, deposition efficiency (DE), microhardness, electrical conductivity, and adhesion strength of Al-Al 2 O 3 coatings was systematically studied. Results show that adding an appropriate amount of Al 2 O 3 to the feedstock can effectively improve the Al-Al splat bonding, electrical conductivity, and adhesion strength of the prepared coating on PEEK substrate, which is attributed to the 'in-situ tamping effect' of spherical Al 2 O 3 particles. Moreover, the molecular structure of the substrate was not damaged or affected after the impact of Al and Al 2 O 3 particles during the CS process. The prepared Al-Al 2 O 3 coating exhibits better performance and provides a novel approach for polymer metallization. [Display omitted] • Al-Al 2 O 3 coatings with different Al 2 O 3 content were deposited on PEEK via CS. • Adding Al 2 O 3 particles can improve electrical conductivity and adhesion strength. • The structure of PEEK was well retained after the impact of Al 2 O 3 particles. • Deposition mechanism of Al-Al 2 O 3 coating on PEEK substrate was discussed. [ABSTRACT FROM AUTHOR]

Cold spray (CS) is an emerging deposition technique for the metallization of polymer material to improve its thermal and electrical properties. In this study, pure Al coatings were deposited on polyether ether ketone (PEEK) substrate by CS. Further, the influence of accelerating gas temperature on microstructure and properties (i.e. deposition efficiency, adhesive strength, electrical conductivity, thermal diffusivity and hardness distribution) of the prepared coatings was systematically investigated. Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), the quantitative analysis of oxygen content and Raman spectra results revealed that the prepared coatings were composed of crystalline metallic Al without obvious oxide phases. Moreover, the polymer structure of PEEK substrate remained intact after high-velocity and high-temperature impact during the CS process. The adhesive strength, electrical conductivity and thermal diffusivity of the Al coating increased with increasing accelerating gas temperature. At the accelerating gas temperature of 380 °C, a dense and thick Al coating with high adhesive strength was obtained in just two deposition passes. Moreover, multi-pass tests (at high nozzle traverse speed) were performed to understand the deposition mechanism of Al coating on PEEK substrate through analyzing cross-section/surface morphology of samples with different thicknesses. Finally, the deposition mechanism of cold sprayed Al coating on PEEK was proposed. [Display omitted] • PEEK was metallized with Al via CS to enhance electrical and thermal properties. • The structure of Al and PEEK remained intact during the CS process. • A dense and thick Al coating was deposited on PEEK at high gas temperature. • Electrical and thermal properties of Al coating increased with gas temperature. • The deposition process of Al coating on PEEK was discussed and summarized. [ABSTRACT FROM AUTHOR]