For many years the use of sodium phosphate has been recommended for boiler applications, both as a pH buffer for corrosion control and as an inhibitor of scale formation. In a recent paper by Panson et al,1 it was concluded that the Na+:PO4--- ratio (r) should not only be maintained below an upper congruent composition (r = 2.85) to avoid excessive alkalinity caused by incongruent precipitation during evaporative concentration, but that the ratio should also be maintained above an invariant composition (r = 2.13) to avoid the corresponding composition shifts towards lower ratio compositions of very high solubility and more acidic conditions.

Subject
Salts, Corrosion rate, Nickel based alloys, Tubes, Solubility, Vapors, Corrosion attacks, Phosphates, Experimental data, Tubing, Immersion, Corrosion coupons, Deposit corrosion
© 1975 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1975
Association for Materials Protection and Performance (AMPP)
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