Hierarchical In 2 O 3 @WO 3 nanocomposites, consisting of discrete In 2 O 3 nanoparticles (NPs) on singlecrystal WO 3 nanoplates, were synthesized via a novel microwave-assisted growth of In 2 O 3 NPs on the surfaces of WO 3 nanoplates that were derived through an intercalation and topochemical-conversion route. The techniques of XRD, SEM, TEM and XPS were used to characterize the samples obtained. The gas-sensing properties of In 2 O 3 @WO 3 nanocomposites, together with WO 3 nanoplates and In 2 O 3 nanoparticles, were comparatively investigated using inorganic gases and organic vapors as the target substances, with an emphasis on H 2 S-sensing performance under low concentrations (0.5-10 ppm) at 100-250 C. The results show that the In 2 O 3 NPs with a size range of 12-20 nm are uniformly anchored on the surfaces of the WO 3 nanoplates. The amounts of the In 2 O 3 NPs can be controlled by changing the In 3+ concentrations in their growth precursors. The In 2 O 3 @WO 3 (In/W ¼ 0.8) sample has highest H 2 S-sensing performance operating at 150 C; its response to 10 ppm H 2 S is as high as 143, 4 times higher than that of WO 3 nanoplates and 13 times that of In 2 O 3 nanocrystals. However, the responses of the In 2 O 3 @WO 3 sensors are less than 13 upon exposure to 100 ppm of CO, SO 2 , H 2 , CH 4 and organic vapors, operating at 100-150 C. The improvement in response and selectivity of the In 2 O 3 @WO 3 sensors upon exposure to H 2 S molecules can be attributed to the synergistic effect of In 2 O 3 NPs and WO 3 nanoplates, hierarchical microstructures and multifunctional interfaces.

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Gapped hollow BaTiO3 nanospheres with an apparent diameter of 93 ± 19 nm (shell thickness of 10–20 nm) were synthesized via a dynamic hydrothermal process using TiO2 sols and Ba2+ ions as the Ti and Ba sources in alkaline aqueous solutions. The phases and morphologies of the BaTiO3 samples were characterized by X-ray diffraction (XRD), SEM, TEM, and Raman spectra. The effects of the hydrothermal temperatures and durations, NaOH concentrations, and Ba/Ti ratios on the formation of gapped hollow BaTiO3 nanospheres were systematically investigated. The optimum conditions for forming gapped hollow BaTiO3 nanospheres are hydrothermal treatment at 180 °C for 10–20 h under a continuous magnetic stirring with NaOH concentrations of about 1 mol/L and molar Ba/Ti ratios of 1.2–1.5. The formation mechanism of the gapped hollow BaTiO3 nanospheres is understood as the combination of the orientated attachment and reversed crystal growth.

A combustible cartridge is made of nitrocellulose, wood fibers and resin. It is easy to absorb moisture in a high‐humidity environment and the NC‐based materials may self‐ignite after storage at higher temperature for a long time. A large number of studies have been carried out to improve the surface protection performance of combustible cartridges usually using a general nitrocellulose varnish. But the heat‐resistance of the nitrocellulose varnish coating is poor. In this article, we develop a composite coating that improves the heat‐resistance and salt wet resistance of combustible cartridges. The new composite coating was prepared by adding BN/silane composite particles and non‐ionic surface active reagent Tween 80 into the nitrocellulose varnish by an optimized composition. The high temperature resistant performance and salt tolerance properties effect of the new composite coating for combustible cartridge were investigated by thermogravimetric experiment, muffle furnace experiment and salt wet resistance test. Compared with the control sample, the coated sample by the new composite coating was able to stand for 138 s at a high temperature of 220 °C, increasing the high temperature resistance time by a maximum percentage of 50 %. In a high‐salt environment, the final water absorption percentage was only 0.2944 % when the coated sample is immersed in a high salt content water at 26 °C for three days, increasing the salt wet resistance by a maximum percentage of 70 %. Results show that the new coating using BN/silane composite particle can improve the high temperature resistant performance and salt tolerance properties of combustible cartridges effectively.

Combustible cartridge case (CCC) is an important charge component which is very suitable for the weapon systems that need light load. It is a kind of nitrocellulosebased porous material which has a low ignition temperature and strong hygroscopicity. Thus, if the surface of the CCC is not protected very well when it is used in modern weapon with faster fire rate, it will be easy to self-ignite in the high-temperature gun barrel and absorb moisture in a high-humidity environment. These problems will worsen both the safety of gun operators and the combustion performance of CCC. However, they are not solved well by current research and industrial practice. Herein, we designed a new composite coating which can improve both the high temperature-resistant performance at a higher temperature and waterproof property of CCC. The boron nitride (BN) and epoxy resin were used to modify silicone resin. The BN and epoxy modified silicone (BEMS) resin, inorganic adiabatic fillers and other additives were mixed together to prepare a BEMS resin based composite coating solution, and then the solution was sprayed on the surface of the combustible cartridge case to form a protective coating. The chemical structure of BEMS resin was investigated by FTIR.The thermal stability of coating films was analyzed by TGA. The high temperature-resistant performance, water contact angle on the surface and waterproof property of the coated CCC were analyzed by muffle furnace experiment, water contact angle tester and immersion test, respectively. Results show that boron nitride and epoxy resin were successfully grafted on silicone resin chains. Compared with control samples, the thermal decomposition rate of the prepared coating films is significantly reduced. The coated CCC will keep 108.8 seconds while not burning at 230 °C. The heat resistant time increased by 16.74 % at 230 °C. The water contact angle on the surface of the coated CCC can reach 105.71°which was improved by 67.01°. After being soaked for one hour, the water absorption of the coated CCC is reduced by 96 % in distilled water and by 99 % in 3.5 wt % of sodium chloride solution. Compared with most present coatings, the new BEMS resin based composite coating which we designed can improve both the high temperature-resistant performance and waterproof property of the CCC significantly and effectively. It provided a new way for study on the protective coating of CCC.