Patent ID: 7951466

Claim:
A heat exchanger for a seawater desalination plant which comprises a titanium alloy material, wherein the titanium alloy material comprises: a Ti—Al alloy comprising 0.50-3.0 mass % of Al, Ti and unavoidable impurities; an oxide film on the Ti—Al alloy; and an Al concentration layer between the Ti—Al alloy and the oxide layer, wherein: the oxide film has a thickness of 1.0-100 nm; the oxide film comprises 50 mass % or more of a crystalline oxide, the film being produced by a process comprising oxidizing the Ti—Al alloy; the Al concentration layer has an average Al concentration in a range of from 0.8-6 mass %; the Al content between the Ti—Al alloy and the oxide layer is 0.8-6 mass %; and the Al concentration of the Al concentration layer is 0.3 mass % or more higher than an Al concentration of the Ti—Al alloy.