Surface passivation of MgAl2O4 spinel powder by chemisorbing H3PO4 for easy aqueous processing
authors Olhero, SM; Ganesh, I; Torres, PMC; Ferreira, JMF
nationality International
journal LANGMUIR
keywords HYDROLYSIS; CERAMICS; BEHAVIOR; OXIDES
abstract A stoichiometric MgAl2O4 spinel (MAS) powder was synthesized by heat treating at 1400 degrees C for 2 h a compacted mixture of alpha-Al2O3 and calcined caustic MgO, followed by crushing and milling. The surface of this powder was then passivated against hydrolysis with H3PO4 and Al(H2PO4)(3) in an ethanol solution. The as-passivated powder could then be dispersed in water using tetramethylammonium hydroxide (TMAH) and an ammonium salt of poly(acrylic acid) (Duramax D-3005) as dispersing agents and gelcast to form green consolidates with relatively high strength (> 15 MPa). The good dispersing behavior of the passivated powder in water was confirmed by the low viscosity of its suspension containing 41-45 vol % solids, demonstrating the viability of replacing organic solvents by water in colloidal processing of MAS-based ceramics. The Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and energy dispersive X-ray (EDAX) studies revealed that only negligible amounts of phosphate ions at the Surface are required to effectively protect the powder from reacting with water.
publisher AMER CHEMICAL SOC
issn 0743-7463
year published 2008
volume 24
issue 17
beginning page 9525
ending page 9530
digital object identifier (doi) 10.1021/la801300m
web of science category Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary
subject category Chemistry; Materials Science
unique article identifier WOS:000258722100054
  ciceco authors
  impact metrics
journal analysis (jcr 2019):
journal impact factor 3.557
5 year journal impact factor 3.702
category normalized journal impact factor percentile 64.177
dimensions (citation analysis):
altmetrics (social interaction):



 


Apoio

1suponsers_list_ciceco.jpg