“…However, chromate is toxic to the environment and hazardous to human beings, leading to it being banned in recent years. Lately, focus has turned to conversion coating that contains no chromium [12,19,20], such as phosphate [21,22], phosphate-permanganate [23][24][25], stannate [26,27], vanadate [28,29], cerate [27,30], lanthanite [31], and LDHs surface coatings [32][33][34][35][36]. Of these, LDH surface coating, as an environmentally friendly coating, has attracted more attention as it brings no pollution to the environment.…”