Highly dense and large bulk Y-zeolites (1.5 mm in thickness and 20 mm in diameter) with a significantly large surface area over 700 m2/g were obtained by a short-term hydrothermal hot-pressing (HHP) treatment at 423 K for 2 h, comparable with the Y-zeolite powder.

In this study, the syntheses of bulks of Y‐zeolite were attempted by a hydrothermal hot‐pressing (HHP) method with various conditions such as the amounts and concentrations of NaOH solution, reaction temperatures, and reaction times. Dense bulks of Y‐zeolite were successfully obtained by this HHP method. Under an optimum synthetic condition of HHP, solidified bulks of Y‐zeolite possessed translucency with high values of specific surface area. Transmission electron microscopy observation of these translucent bulks of Y‐zeolite showed that their microstructures were densified like polycrystalline ceramics sintered by heat treatments and no amorphous phase was observed at the boundaries of Y‐zeolite grains. As a result, in these unique bulks of Y‐zeolite synthesized by the HHP method, the microporous network was thoroughly connected at the grain boundaries of Y‐zeolite.

Synthesis of bulky Y-zeolite was attempted by a hydrothermal hot-pressing (HHP) method. These bulky products synthesized under hydrothermal conditions were identified as Y-zeolite single phase. Especially, bulky Y-zeolite having translucency, high density and large surface area was obtained by HHP treatment at 423K for 2h with 17wt% of 5M-NaOH solution. This solidified zeolite like single-crystal was considered to be made by dissolution and precipitation mechanism. High-density bulky zeolites can be expected as novel molecular sieves and catalysts with high activity.

The copper alloys, which were added Nickel show high corrosion resistance. Therefore, they are generally used in environments of poor quality fuel. However, it is expected that we reduce the amount of Ni in copper alloy, due to increase of Nickel consumption in recent years. We used five different types of sintered material samples that are different in the content of Nickel in the present study, to investigate the influence of Ni content to corrosion resistance quantitatively. These samples were used for the experiment of open circuit potentials, anodic and cathodic polarization curves measurements. To simulate environment in poor quality fuel we employed solution of 0.5 M Na2S + 0.1 M NaOH (pH = 13.05). The experiment of open circuit potentials shows that samples that the content of Nickel is less than 42 mass% were formed passivation film on surface of sample during aeration. The experiment of polarization curves measurements show that the each sample was implied behavior of forming passivation film corresponding to potential-pH diagram of Cu in anodic region basically. In addition, the 36.4 mass% Nickel was remarkably improved corrosion resistance.

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