THE following comments are directed to the sections (2) ‘‘revisit to the grain growth problems in alumina’’ and (3) grain growth without a liquid phase in the article of concern. The purpose of this comment is to challenge the authors’ assertions and refute the following arguments, namely, first that ‘‘MgO can be considered a very effective grain growth promoter in the sintering of alumina,’’ s...

Silica nanoparticles (NPs) belong to the industrially most important NP types. In a previous study it was shown that amorphous SiO(2) NPs of 12.5 and 27.0 nm are stable in algal growth inhibition assays and that their ecotoxic effects are related to NP surface area. Here, it was hypothesized and demonstrated that an alumina coating completely alters the particle-particle, particle-test medium a...

We employ periodic density functional theory to explore the effect of cyclic tensile loading on the behavior of alumina in the threshold region of crack formation. We find evidence for nanoscale fatigue when the alumina lattice is subjected to uniaxial tensile loading and unloading and tensile stresses normal to the applied load. It is possible that such atomic-scale fatigue impacts the durabil...

Spark plasma sintering (SPS) method, as plasma activated sintering, is a method applicable for rapid sintering of metals and ceramics. Owing to the advantage of rapid heating, the alumina ceramics obtained by SPS have a grain size and density comparable to those of hot pressed ones. The increase of densification rate may be related to some difference in ion transport characteristics. This study...

spark plasma sintering (sps) method, as plasma activated sintering, is a method applicable for rapid sintering of metals and ceramics. owing to the advantage of rapid heating, the alumina ceramics obtained by sps have a grain size and density comparable to those of hot pressed ones. the increase of densification rate may be related to some difference in ion transport characteristics. this study...

A new rapid, very simple and one-step sol-gel strategy for the large-scale preparation of highly porous γ-Al₂O₃ is presented. The resulting mesoporous alumina materials feature high surface areas (400 m² g-1), large pore volumes (0.8 mL g-1) and the γ-Al₂O₃ phase is obtained at low temperature (500 °C). The main advantages and drawbacks of different preparations of mesoporous alumina materials ...

Rheological properties of aqueous suspensions (48 vol%) of zircon-alumina mixtures containing different amounts of polyelectrolyte as dispersant were studied. Slip casting in a plaster mold and pressure filtration at 8 MPa experiments were performed to correlate the rheological properties of the suspensions with the relative density of green casts. Flow curves fitted satisfactorily to the Casso...

the intake of antioxidants intake has been reported to be inversely associated with the incidence of coronary artery disease. to clarify the possible role of lipophilic antioxidants in prevention of atherosclerosis, we investigated the effects of lycopene on the susceptibility of low-density lipoprotein (ldl) to oxidative modification. in this study, “lycopene” was added to plasma and incubated...

This article is an introduction to anodization of aluminum, which is a subject of electrochemistry. Anodization of aluminum under a controlled electrochemical condition yields ordered porous alumina with a close-packed hexagonal array of cylindrical nanochannels. The diameter, density, and aspect ratio of pores can be tightly controlled by varying the anodization condition, which makes the poro...