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A facile means for obtaining submicrometer carbon fibers with a nanoporous structure is presented. A mixture of polyacrylonitrile (PAN) and a copolymer of acrylonitrile and methyl methacrylate (poly(AN-co-MMA)) in dimethylformamide was electrospun into submicrometer fibers with a microphase-separated structure. During the followed oxidation process, the copolymer domains were pyrolyzed, resulting in a nanoporous structure that was preserved after carbonization. The microphase-separated structure of the PAN/poly(AN-co-MMA) electrospun fibers, the morphology, and porous structure of both the oxidized and the carbonized fibers were observed with scanning electron microscopy and transmission electron microscopy. The carbon fibers have diameters ranging from several hundred nanometers to about 1 microm. The nanopores or nanoslits throughout the fiber surface and interior with diameters of several tens of nanometers are interconnected and oriented along the longitudinal axis of the fibers. This unique nanoporous morphology similar to the microphase-separated structure in the PAN/poly(AN-co-MMA) fibers is attributed to the rapid phase separation, solidification, as well as the stretching of the fibers during electrospinning. The pore volume and pore size distribution of the carbonized fibers were investigated by nitrogen adsorption and desorption.

In this study, polycaprolactone (PCL) and polylactic acid (PLA) coatings were prepared on the surface of high purity magnesium (HPMs), respectively, and electrochemical and dynamic degradation tests were used to investigate the degradation behaviors of these polymer-coated HPMs. The experimental results indicated that two uniform and smooth polymer films with thicknesses between 15 and 20 µm were successfully prepared on the HPMs. Electrochemical tests showed that both PCL-coated and PLA-coated HPMs had higher free corrosion potentials (E(corr)) and smaller corrosion currents (I(corr)) in the modified simulated body fluid (m-SBF) at 37 °C, compared to those of the uncoated HPMs. Dynamic degradation tests simulating the flow conditions in coronary arteries were carried out on a specific test platform. The weight of the specimens and the pH over the tests were recorded to characterize the corrosion performance of those samples. The surfaces of the specimens after the dynamic degradation tests were also examined. The data implied that there was a special interaction between HPM and its polymer coatings during the dynamic degradation tests, which undermined the corrosion resistance of the coated HPMs. A model was proposed to illustrate the interaction between the polymer coatings and HPM. This study also suggested that this reciprocity may also exist on the implanted magnesium stents coated with biodegradable polymers, which is a potential obstacle for the further development of drug-eluting magnesium stents.

Boron nitride nanotubes (BNNTs) that can directly grow on the surface of stainless steel mesh via a vapor‐liquid‐solid (VLS) growth process are developed by a simple, cheap and scalable approach. The resultant superhydrophobic and superoleophilic BNNT‐coated meshes can efficiently separate insoluble oil from water. Most importantly, such BNNT‐coated meshes are stable and durable making it a promising candidate for oil‐polluted water treatments.

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Reviewer #1: Review of Acta Met A-18-1525 Effect of microstructure on early oxidation of MCrAlY coatings by Ying Chen et al. This paper describes the early oxidation of both an LPPS and HVOF bond coat. The materials is excellently presented in nearly flawless English. In the end the rapid transport of Aluminum by grain boundaries explains nearly all the is observed. Much background is already known and well review in the paper. The paper does an excellent job of putting all the pieces together and extensive experimental results are shown including PLPS (oxide too thin for XRD) SEM and TEM using multiple techniques in the TEM. They then model the results to explain in a semi quantitative way why the results are the way they are. Generally a very nice paper. This reviewer enjoyed reading this well written paper. One caveat is that this reviewer although very familiar with the results in this filed is not an expert on which exact references are most appropriate. The following things can be improved. 1. For less experienced readers they should give the composition and crystal structure of gamma and beta phases. Reply: We have added a table (Table 2) listing the compositions of the β and γ-phase determined by energy dispersive X-ray spectroscopy (see Table 2 and corresponding text in Line 11-12, Page 5) The crystal structures of the γ and β-phases are given in Introduction (Line 8-9, Page 2). 2. On page 12 they state that equilibrium imposes strict restrictions on the multi-phase alloy. True but how does this play into the discussed behavior. Reply: This statement is to stress that the thermodynamic equilibrium in the two-phase NiCoCrAlY coating prevents the interaction of , and in the alloy. We have added this point into the text (Line 7-8, Page 13) 3.p. 3 the bond coats were over 200 microns thick. Probably not important given the short heating but typical bond coats are much thinner. If there is a reason for this choice it is worth stating. Reply: The reason for using a relatively thick coating is to eliminate the effect of substrate/coating interfusion on the early oxidation of the coatings. This statement has been added into the text (Line 41-43, Page 3) 4.P.4 It says the samples were heated to 1150C at 200 C/minute and air cooling. At this rate could be a question of will the samples heat fast enough to follow the furnace temperature setting and the question of how fast the *Response to Reviewer Reply: "MCrAlY" has been replaced by "NiCoCrAlY" throughout the text after "2. Materials and Methods".

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