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MgO/KH2PO4 and Curing Moisture Content in MKPC Matrices to Optimize the Immobilization of Pure Al and Al-Mg Alloys.
Fernández-García, Carla; Alonso, María Cruz; Bastidas, José María; García-Lodeiro, Inés; Fernández, Raúl.
Affiliation
  • Fernández-García C; Institute of Construction Science "Eduardo Torroja" (IETcc), CSIC, Serrano Galvache 4, 28033 Madrid, Spain.
  • Alonso MC; Institute of Construction Science "Eduardo Torroja" (IETcc), CSIC, Serrano Galvache 4, 28033 Madrid, Spain.
  • Bastidas JM; National Centre for Metallurgical Research (CENIM), CSIC, Ave. Gregorio Del Amo 8, 28040 Madrid, Spain.
  • García-Lodeiro I; Institute of Construction Science "Eduardo Torroja" (IETcc), CSIC, Serrano Galvache 4, 28033 Madrid, Spain.
  • Fernández R; Department of Geology and Geochemistry, Faculty of Sciences, Autonomous University of Madrid (UAM), 28049 Madrid, Spain.
Materials (Basel) ; 17(6)2024 Mar 08.
Article in En | MEDLINE | ID: mdl-38541417
ABSTRACT
Magnesium Potassium Phosphate Cements (MKPCs) are considered a good alternative for the immobilization of aluminium radioactive waste. MKPC composition and moisture curing conditions are relevant issues to be evaluated. The corrosion of pure aluminium (A1050) and AlMg alloys (AA5754) with 3.5% of Mg is studied in MKPC systems prepared with different MgO/KH2PO4 (M/P) molar ratios (1, 2, and 3M) and moisture curing conditions (100% Relative Humidity (RH) and isolated in plastic containers (endogenous curing)). The Al corrosion potential (Ecorr) and corrosion kinetic (icorr and Vcorr) are evaluated over 90 days. Additionally, the pore ion evolution, the matrix electrical resistance, the pore structure, and compressive strength are analysed. The corrosion process of Al alloy is affected by the pH and ion content in the pore solution. The pore pH increases from near neutral for the 1M M/P ratio to 9 and 10 for the 2 and 3M M/P ratio, increasing in the same way the corrosion of pure Al (AA1050) and AlMg alloys (AA5754). The effect of Mg content in the alloy (AA5754) becomes more relevant with the increase in the M/P ratio. The presence of phosphate ions in the pore solution inhibits the corrosion process in both Al alloys. The MKPC physicochemical stability improved with the increase in the M/P ratio, higher mechanical strength, and more refined pore structure.
Key words

Full text: 1 Collection: 01-internacional Database: MEDLINE Language: En Journal: Materials (Basel) Year: 2024 Document type: Article Affiliation country: Spain Country of publication: Switzerland

Full text: 1 Collection: 01-internacional Database: MEDLINE Language: En Journal: Materials (Basel) Year: 2024 Document type: Article Affiliation country: Spain Country of publication: Switzerland