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dissolution-process
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The influence of heat treatment and hot deformation conditions on γ′ precipitate dissolution of Nimonic 115 superalloy
, Article International Journal of Advanced Manufacturing Technology ; Volume 45, Issue 9-10 , 2009 , Pages 841-850 ; 02683768 (ISSN) ; Sadeghi, M. H ; Akbarzadeh, A ; Cheraghzadeh, M ; Sharif University of Technology
Abstract
In precipitation hardenable materials, it is desirable to determine the precipitate dissolution temperature for homogenizing the microstructure by controlling the size and distribution of the precipitates. In this research, the influence of various heat treatment and hot deformation conditions on the kinetics of γ ′ dissolution and its morphological evolution in Nimonic 115 was studied. In addition, hot deformation behavior of the material was investigated using hot compression experiments at varying temperature (between 1,050°C and 1,175°C) and strain rates (between 0.01 and 1 s-1) up to a true strain of 0.8. The values obtained for the solvus temperature of γ ′ precipitates by two methods...
Chemical corrosion and gamma-ray attenuation properties of Zr and Ti containing lead silicate glasses
, Article Journal of Nuclear Materials ; Volume 385, Issue 3 , 2009 , Pages 527-532 ; 00223115 (ISSN) ; Raisali, G ; Sadrnezhaad, K ; Alipour, A ; Sharif University of Technology
2009
Abstract
Lead silicate glasses (LSGs) have high gamma-ray attenuation but low chemical durability properties. In this work, LSGs with (55.5-68.5 wt%) PbO content containing ZrO2 and TiO2 additions were produced. The chemical corrosion of various produced LSGs in 0.5 N HNO3 aqueous solution and determination of their gamma-ray attenuation coefficients for 60Co and 137Cs sources were investigated. The weight loss measurements, the SEM micrographs, the EDS analysis of the sample surfaces and the ICP analysis of solution were used to characterize the dissolution process. The effects of PbO content, ZrO2 and TiO2 additives on chemical corrosion, and also the effect of PbO on gamma-ray attenuation...
Hydrolysis kinetics of lead silicate glass in acid solution
, Article Journal of Nuclear Materials ; Volume 389, Issue 3 , 2009 , Pages 427-431 ; 00223115 (ISSN) ; Sadrnezhaad, Kh ; Raisali, G ; Hamidi, A ; Sharif University of Technology
2009
Abstract
Hydrolysis kinetics of the lead silicate glass (LSG) with 40 mol% PbO in 0.5 N HNO3 aqueous acid solution was investigated. The surface morphology and the gel layer thickness were studied by scanning electron microscopy (SEM) micrographs. Energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma spectroscopy (ICP) were used to determine the composition of the gel layer and the aqueous solution, respectively. The silicon content of the dissolution products was determined by using weight-loss data and compositions of the gel layer and the solution. The kinetic parameters were determined using the shrinking-core-model (SCM) for rate controlling step. The activation energy...