| 摘要 |
PURPOSE: A preparation method of an acid proof heat exchanger coated with ceramic powder or acid proof metal powder with a fixed thickness is provided which can produce an economical low temperature corrosion proof heat exchanger and extend its life expectancy. CONSTITUTION: One or more single components or composite components selected from a ceramic material having a high melting point such as Al2O3, ZrO2, Cr2O3, TiO2, SiO2, glass or SiC, SiN, CrC, TiN, TiC, B4C or a non-oxide high melting point material such as SiC, SiN, CrC, TiN, TiC, B4C as a coating agent are melted at 16,000°C and coated on the surface of a tube or a heat transfer plate of a heat exchanger at a speed of at least 600 m/sec. One or more metal oxides selected from alumina, zirconia and titania powder are coated on the upper layer of base metal with a thickness of 20-100 micrometer. And one or more powder selected from Al-Si, Mg-Al, brass, and Cu-Al alloy powder are undercoated on the surface of treated base plate with a thickness of 20-200 micrometer or more at a speed of Mach 2-3 in the atmosphere by a plasma method and then one or more powder of the above metal oxide or non-metal oxide are coated on the upper layer of the undercoated base plate with a thickness of 30-150 micrometer. A cathode polarized curve(room temperature, 20% H2SO4) of alumina coated sample plate is shown below.
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