Patent ID: 9702052
Date: 2017-07-11
CPC Classifications: C25D

Claim:
1. A forming method of a thermal insulation film, comprising: a first step of forming an anode oxidation coating film on an aluminum-based wall surface, the anode oxidation coating film including micro-pores each having a diameter of micrometer-scale and nano-pores each having a diameter of nanometer-scale; a second step of abrading a surface of the anode oxidation coating film with abrasive powders to a prescribed depth to form an abraded surface and bringing the abrasive powders into the micro-pores located at the abraded surface; and a third step of forming a protection film on the abraded surface to produce a thermal insulation film including the anode oxidation coating film and the protection film, wherein the abrading reduces a thickness of the anode oxidation coating film in a direction from the surface of the anode oxidation coating film toward the aluminum-based wall surface.