公开(公告)号：US20240301560A1

公开(公告)日：2024-09-12

申请号：US18175261

申请日：2023-02-27

Applicant: GM Global Technology Operations LLC

Inventor： Adam Paul Rabe ,  Zhe Li ,  Matthew George Keast ,  Jacob Alexander Rabe

IPC: C23C22/50 ,  C23C22/78

CPC classification number: C23C22/50 ,  C23C22/78

Abstract: A method of coating an automotive part for an electric drive unit is provided. The method comprises providing a part comprising a body having an outer surface and introducing the part in an aqueous coating solution comprising sodium metabisulfite and citric acid to form residual oxides on the outer surface defining a sample-water interface. The method further comprises emitting ultrasonic waves in the coating solution to generate acoustic cavitation activity at the sample-water interface and continuously form oxygen and hydrogen species. The citric acid arranged to activate the outer surface to allow for the reaction with the oxygen and hydrogen species forming iron hydroxide. The sodium metabisulfite arranged to react with the iron hydroxide generating iron oxysulfide such that the iron oxysulfide reacts with the oxygen and hydrogen species to produce iron oxide and iron sulfide on the outer surface defining a black oxide coating.