Aluminium hydroxide

About: Aluminium hydroxide is a research topic. Over the lifetime, 2043 publications have been published within this topic receiving 22032 citations. The topic is also known as: Al(OH)3 & Amphojel.

Influence of starting materials on the reaction sintering of mullite–ZrO2 composites

Abstract: Mullite–zirconia composite materials were prepared by reaction sintering of α-alumina, aluminium hydroxide and aluminium nitrate as alumina sources, and zircon powder. The compaction of different calcined powders, and the reaction development, densification behaviour and microstructural investigations of different samples were examined at temperatures ranging from 1350 to 1600°C for 2 h holding time. X-ray diffraction peaks suggested fully developed mullite and zirconia phases by reaction sintering of zircon and aluminium nitrate, and showed more retained tetragonal ZrO 2 at 1600°C. Relatively dense sintered samples were obtained by the mixture of zircon and α-alumina powders. The morphology of intergranular ZrO 2 particles was found dependent on the growing conditions because of the using of different starting materials.

Fabrication and characterization of zirconia-toughened alumina obtained by inorganic and organic precursors

Abstract: In zirconia-toughened alumina (ZTA) the martensitic transformation of zirconia (tetragonal→ monoclinic) is at the origin of toughening. If the zirconia particles have a mean grain size less thand’ c, they remain tetragonal; if their size is betweend’ c andd c (d c>d’ c), they are stress-induced transformed into the monoclinic form; if their size is larger thand c, particles are transformed. We prepared ZTA using different precursors and compared their microstructures. The coprecipitation of aluminium and zirconium chlorides gives an hydroxide mixture. Thus the zirconium hydrate is amorphous, and the aluminium hydroxide structure varies with the precipitation temperature and pH values at the end of the neutralization. Alumina is mixed with zirconia obtained by gas-phase reaction. Zirconia is prepared by vaporization of zirconium chloride in an oxygen-hydrogen flame. Alumina powder is impregnated by a zirconium acetate solution. Zirconium acetate is thermally decomposed in a spray-dryer, then by calcination. The cohydrolysis of II Al-butoxide and IV Zr-propoxide was carried out in an alkaline solution. The hydrolysis pH (10 or 12) changes the grain size of the oxide powders. Mechanical property measurements and microstructural analysis allow a comparison of the different composites. The mean grain-size evolution differs according to the preparative route, and may be varied by different elaboration parameters. Fine microstructures were always observed. The mean grain size of dispersed zirconia being very small (neard’ c), we observed a little influence of transformation toughening. We noticed a large increase in rupture strength, while toughness was not noticeably improved.

Environment-friendly type charcoal composite material and its preparation method

Abstract: The invention provides an environment-friendly type composite charcoal material, wherein the its components comprises (by weight portion): resin 10-50%, fabric 1-20%, charcoal powder 40-80%, quartz or crystal powder 05-2%, aluminium hydroxide 1-10%