| 摘要 |
The present invention provides a gas flow member capable of preventing a decrease in engine output and a decrease in exhaust gas purification performance even when the surface of a housing component of a turbo engine or the surface of an exhaust system component is a surface having high roughness or waviness. The gas flow member includes a metal base having a gas flow surface and a surface coat layer containing an amorphous inorganic material and a crystalline inorganic material, the gas flow surface of the base being coated with the surface coat layer, wherein the crystalline inorganic material contains at least one selected from the group consisting of calcia, magnesia, ceria, alumina, and zirconia, the gas flow surface of the base is a surface having a ten-point average roughness RzJIS of a roughness curve of 10 to 50 µm and having a maximum waviness height Wz of a waviness curve of 15 to 100 µm, roughness and waviness of the gas flow surface of the base are covered with the surface coat layer, the surface coat layer has an average thickness of more than 50 µm, and a coated gas flow surface which is a surface formed by covering the gas flow surface of the base with the surface coat layer is a smooth surface having a ten-point average roughness RzJIS of a roughness curve of 5 µm or less and is also a flat surface having a maximum waviness height Wz of a waviness curve of 10 µm or less. |
