| 摘要 |
PURPOSE:To effectively prevent the intergranular stress corrosion cracking of the Ni-based alloy which is brought into contact with a deaerated alkaline soln. at high temp. by adding a specified amt. of a cyclic amine to the deaerated alkaline soln. CONSTITUTION:From 0.3ppm to 1%, based on the weight of a soln., cyclic amine such as morpholine, cyclohexylamine, and piperazine is added to the deaerated alkaline soln. to be used in a heat exchanger, etc., and exposed to a high temp. An increase in the corrosion potential of an Ni-based alloy due to the impurities such as Fe3O4, Cu, Cu2O, and CuO which are eluted into the soln. in the form of sludge or scales and deposited in the high-temp. deaerated alkaline soln. is controlled by the cyclic amine. Furthermore, the entrance of the potential into the corrosion cracking generating potential region is also prevented. As a result, even when a member consisting of an Ni-based alloy is incorporated into an existing plant, the corrosion cracking of the member can be prevented without disassembling the plant.
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