Mechanical behavior and microstructure of porous needle: Aluminum borate (Al18B4O33) and Al2O3-Al18B4O33 composites

Abstract

In this article we assess and compare the complex mechanical behavior of two complex microstructure ceramics material formed within the reaction sintering framework Two comparable pairs of materials with respectively similar microstructures were obtained by reaction sintering from boric acid and alumina. Two single phase porous ceramics were compared with two composite (1:1) porous ceramic. The first and second phases were aluminum borate needles (Al 18 B 4 O 33) and alumina (Al 2 O 3). The four with comparable grain size and analogous apparent porosities: in diameter (≈ 0.7 µm) and in volume fraction (≈ 45%). The mechanical behavior was studied by means of the diametral compression test at low displacement rate and explained in terms of the texture, microstructure features evaluated by mercury intrusion porosimetry and scanning electron microscopy. Single Al 18 B 4 O 33 phase porous materials presented higher mechanical strengths than the composite materials. Within the respective microstructural configurations the whisker thickness did not affect significantly the mechanical behavior and parameters. A well-defined fragile behavior was observed and described in the composite material. On the other hand the single Al 18 B 4 O 33 needle porous material presented a distinctive behavior with local discontinuities without loss of integrity in the diametral stress behavior, and achieved strength up to 50% higher than the corresponding composite.

Microstructural evolution and kinetics analysis of aluminum borate ceramics via solid‐state reaction synthesis

“…In recent years, a variety of techniques have been developed to prepare ABCs including solid‐state reaction, sol‐gel method, and molten salt synthesis method . Iizuka et al used aluminum hydroxide, boric acid, and an additive of nickel oxide as the raw materials to fabricate ABCs with excellent physical properties by means of solid‐state reaction .…”

High macroscopic neutron capture cross section ceramics based on bauxite and Gd2O3

“…The derivative curve of the TG (DTG) was also employed for this purpose. To understand the sintering behavior, thermomechanical analysis on a vertical prismatic (20.0 x 3.5 x 3.5 mm 3 ) sample was performed; with a 10 °C/min heating rate in air atmosphere (TMA Rigaku Evo plus II, Japan) [25,26].…”

Partially stabilized zirconia (3Y-ZrO2) aluminum borate (Al18B4O33) needles composite materials by direct sintering

“…On the other side, Aluminum borate (AB: Al 18 B 4 O 33 ) present high refractoriness up to 1300 °C, accompanied by chemical inertness in some specific environments [14][15][16], with adequate thermo-mechanical behavior for several applications that include alloy reinforcement phase [14].…”

“…It is important to compare the potentiality of these composites with previous studied ones. In another article we also presented the technological features of an alumina-aluminum borate composite [15]. In these, the structural application of this family of ceramics is encouraged, especially for their density, cost and needle morphology merits.…”