A previous study had shown that exposure to degraded propylene glycol(PG)/water solution (1:1 in volume) at 80°C for 60 days or to boiling PG/water solution for 30 days induce remarkable localized attack on aluminium alloy AA 6351 (nominal composition: 1% Si, 0.6% Mg, 0.3% Mn, balance Al). In the present work degradation of the solution was achieved by holding the PG/water solution at its boiling temperature for 30 days in contact with AA 6351. The observed localized attack was mainly attributed to the action of copper ions dissolved from the aluminum alloy (copper content = 0.07%) and then deposited as small spots acting as efficient cathodic areas. The objective of this work was to examine the feasibility of enhancing pitting resistance of AA 6351 by adding suitable inhibitors to the solutions. The compounds used were two inorganic salts: sodium molybdate and sodium tungstate and two derivatives of pyrimidine: 2-aminopyrimidine (2AP) and 2-hydroxypyrimidine (2HP).
Inhibition of localized attack on the aluminium alloy AA 6351 in glycol/water solutions
MONTICELLI, Cecilia;
1989
Abstract
A previous study had shown that exposure to degraded propylene glycol(PG)/water solution (1:1 in volume) at 80°C for 60 days or to boiling PG/water solution for 30 days induce remarkable localized attack on aluminium alloy AA 6351 (nominal composition: 1% Si, 0.6% Mg, 0.3% Mn, balance Al). In the present work degradation of the solution was achieved by holding the PG/water solution at its boiling temperature for 30 days in contact with AA 6351. The observed localized attack was mainly attributed to the action of copper ions dissolved from the aluminum alloy (copper content = 0.07%) and then deposited as small spots acting as efficient cathodic areas. The objective of this work was to examine the feasibility of enhancing pitting resistance of AA 6351 by adding suitable inhibitors to the solutions. The compounds used were two inorganic salts: sodium molybdate and sodium tungstate and two derivatives of pyrimidine: 2-aminopyrimidine (2AP) and 2-hydroxypyrimidine (2HP).I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
