| 摘要 |
<p>847,981. Preventing corrosion. ATOMIC ENERGY OF CANADA Ltd. Oct. 8, 1958 [Oct. 8, 1957], No. 32135/58. Class 123(1) Corrosion of aluminium-nickel alloys containing from 0À5 to 5% of nickel which are immersed in flowing water at a temperature of from 150 to 350‹C. is inhibited by adding silicic acid to the water to form a thin, durable coating of a complex aluminium silicate on the alloy. The amount of silicic acid added ranges from 100 parts per million to that amount which produces saturation at the working temperature and is preferably from 800 to 1000 parts per million. The acid may be added by adding sodium or potassium silicate and removing the cation in a cation exchange bed connected in parallel with the water flow system until the pH of the solution is not less than 5, the resulting solution then being equilibrated with a standard mixed ion exchange bed to maintain its concentration, purity and pH level. The invention is of particular application to the protection of the fuel rod sheaths in a water-cooled nuclear reactor, the silicate being added to the recirculating cooling water flow. To produce an initial film of silicate on the sheaths they may be heated to working temperature in a solution of silicic acid for a period of from one to seven days.</p> |
