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Idle time and gelation behavior in gelcasting process of PSZ in acrylamide system

Sahraei Khanghah, N ; Sharif University of Technology | 2010

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  1. Type of Document: Article
  2. Publisher: 2010
  3. Abstract:
  4. Gelcasting is a novel forming method in fabricating complex three dimensional ceramic parts, and has many parameters and characteristics required to be specified. Up to now, few articles have been published on determination of the idle time of gelation precisely. In this work the chemorheology of gelation in aqueous solution of acrylamide and N, N′ methylenebisacrylamide monomer, and zirconia (PSZ) suspensions of this solution was investigated. As the viscosity of gel system increases abruptly in gelation point, idle time can be determined precisely by measurement of viscosity against time. Idle time can also be determined through temperature measurement against time since the reaction of gelation is exothermic. This work compared these two methods of measurement of idle time. It was investigated in this work that idle time as a critical parameter in gelcasting, decreases with increasing of variables, such as acrylamide, N,N′ methylenebisacrylamide and initiator concentrations and also temperature. In addition, presence of ceramic powder also enhances the rate of gelation intensely. In comparison of the two methods, it can be concluded that the rheological method is more reliable because the idle time can be perceived more rapidly after the beginning of the gelation
  5. Keywords:
  6. Gelcasting ; Idle time ; Organic precursors ; Rheological properties ; Acrylamides ; Aqueous solutions ; Ceramic powder ; Chemorheology ; Critical parameter ; Gel casting process ; Gel systems ; Gelation behavior ; Gelation point ; Initiator concentration ; Methods of measurement ; Methylene bisacrylamide ; Organic precursor ; Rheological method ; Rheological property ; Amides ; Ceramic materials ; Coagulation ; Gels ; Innovation ; Rheology ; Suspensions (fluids) ; Temperature measurement ; Viscosity ; Zirconia ; Gelation ; Galss
  7. Source: Ceramic Transactions, 31 May 2009 through 5 June 2009 ; Volume 212 , JUL , 2010 , Pages 105-113 ; 10421122 (ISSN) ; 9780470876466 (ISBN)
  8. URL: http://onlinelibrary.wiley.com/doi/10.1002/9780470880456.ch10/summary