Powder XRD and 31P and 27Al solid state MAS NMR investigations of phase transformations in aluminium phosphate bonded Al2O3–MgAl2O4 refractories

Phase development of phosphate‐bonded Al2O3‐MgAl2O4 high‐temperature ceramics: XRD and solid‐state NMR investigations

“…In this notation, n describes the number of oxygen-bridged P-O-P cross-links on a phosphorus (n = 0; 1; 2; 3) and m the number of counter cations M (Al, Mg, Ca, Zr) as next nearest neighbors (m = 0; 1; 2; 3; 4). 22,23 The structural connectivity reveals, for example, a Q 0 (2Al) unit results in a weaker degree of P-cross-linking than a Q 0 (4Al) unit, for instance, due to hydroxyl groups.…”

“…22 Within the scope of this study, these investigations serve as a reference and shall be summarized briefly as follows: The aluminum phosphate acts as a network forming agent by developing a P-cross-linked A survey of the published literature modeling of CMCs has been studied by a n ers. Processes that have been modeled CVD, 17,18 CVI, [19][20][21][22] and Sol-Gel Infiltrat of alumina matrix in eight-harness satin has been studied numerically in Ref. [ proaches used in the above work general ing the flow of a high viscosity resin thr and modeling the chemical reactions and during processing.…”

“…The diffractograms of the ceramic compositions bonded with water-soluble phosphates (Figures 2-4 A survey of the published literature modeling of CMCs has been studied by a n ers. Processes that have been modeled CVD, 17,18 CVI, [19][20][21][22] and Sol-Gel Infiltrat of alumina matrix in eight-harness satin has been studied numerically in Ref. [ proaches used in the above work general ing the flow of a high viscosity resin thr and modeling the chemical reactions and during processing.…”

“…[7][8][9]40,41 A survey of the published literature shows that process modeling of CMCs has been studied by a number of researchers. Processes that have been modeled include RMI, 15,16 CVD, 17,18 CVI, [19][20][21][22] and Sol-Gel Infiltration. 23 Impregnation of alumina matrix in eight-harness satin Nextel 610 fabric has been studied numerically in Ref.…”

“…[19][20][21] In a preliminary study, the binding mechanism of an Al(H 2 PO 4 ) 3 bonded Al 2 O 3 -MgAl 2 O 4 ceramic body was comprehensively investigated by means of MAS NMR spectroscopy and powder X-ray diffraction analysis (PXRD). 22 P-cross-linked, amorphous Al-P-O-H phosphate structures resulting from reactions between the phosphate binder and the ceramic components were identified and characterized to be the active bonding phase. The objective is to extend the study to alternative phosphate binders with other cations, in order to use the research results to systematically compile that substance information that is required to optimize the use of phosphate binders for high-temperature applications.…”