Effect of Banana Fiber in the Properties of Clayey Ceramic

Banana is a typical fruit that grows in warm tropical regions of the world including everywhere in Brazil. The production of the banana plant takes place year round and its pseudo-stem, mostly made of lignocellulosic fibers, is discarded as waste. The banana fibers posses a relatively higher content of potassium, which is an alkaline element of interest to the production of common clayey ceramics, like red brick, owing to its fluxing action. Therefore, the present work investigated the effect of banana pseudo-stem fiber incorporation on the technological properties of a clayey ceramic fired at 700, 900 and 1050°C. In spite of a possible contribution to liquid phase formation, the incorporation of up to 10 wt% of banana fiber impaired the ceramic properties, especially when fired at 1050°C

Investigation on the Microstructures and Creep Properties of Mg-7~11wt. %Zn-4 wt. %Al Based Alloys

Recent studies indicated that Mg-(7-11)Zn-4Al (the composition of the alloys in the present paper are given in weight percentage.) based alloys exhibited good creep resistance and additions of trace alkaline elements to the alloys further improved the mechanical properties at elevated temperatures. In order to optimize the zinc concentration and reveal the effect of small amount of alkaline element additions to Mg-Zn-Al ternary alloys on their microstructure and elevated temperature creep resistance, five alloys with compositions of Mg-7Zn-4Al, Mg-9Zn-4Al, Mg-11Zn-4Al, Mg-11Zn-4Al-0.2Ca and Mg-11Zn-4Al-0.6Ca, respectively, were prepared in the present investigation and the microstructure and creep properties of these alloys were studied.

Preparation of Porous Mullite Ceramics by Fly Ash/Al Compositions

Porous mullite was prepared from a reactive mixture of Al metal powder and the fly ash produced by power plant. The sintering ceramics was characterized for the pore structure and phase identification studies. It was found that the sintered specimen expands at first (1300-1400°C) and then shrinks which was correspondence to the changing of open porosity. The expansion was attributed to the fact that the alumina produced from the oxidation reaction of Al powder made the volume larger than the starting mixtures. At 1550°C, it was inferred that the alkaline element in the fly ash made the mullite decomposed then destroyed the mullite structure. The SEM photographs suggested us that the pore diameter of the sintered ceramics might be adjusted by adding Al powder with different grain sizes. Moreover, because of the rod-like mullite produced in the pores, Mg metal addition could develop the further modification of the pore structure with similar porosity (47% at 1400°C/4h) compared with that (53%) with 0wt % Mg metal powders.