Environment-friendly and chromium-free passivation of copper and its alloys

Study on the preparation of ascorbic acid reduced ultrafine copper powders in the presence of different protectants and the properties of copper powders based on methionine protection

“…Among them, adsorbed water was also detected near 535.60 ± 0.20 eV in the copper powders without protectants and with SSC as a protectant, while it was absent from the surfaces of the copper powders with Met and CTAB as protectants, which was attributed to the methylthio group (CH 3 S–) in Met and the hydrophobic functional group (HO–) in CTAB as a hydrophobic functional group that hinders the adsorption of water, and further slows down the oxygen erosion. 29 However, there is a weak peak attributed to C–O at 532.71 eV in Fig. 6(f) , which is provided by a small amount of unoxidized hydroxyl oxygen in C 6 H 8 O 6 .…”

Composite protective effect of benzotriazole and 2-mercaptobenzothiazole on electroplated copper coating

“…11,22,39 However, only a small part (about 8%) of monovalent copper on the surface of copper electrode participates in the formation of [Cu( i )–BTA], and most of the monovalent copper may react with dissolved oxygen to form Cu 2 O, two relations can be written as eqn (6). 17,41 This process can be expressed by Fig. 8c.BTAH ⇄ BTA − + H + Cu( i ) + BTAH →Cu( i )–BTA + H + n (Cu + ) → n (Cu–BTA) + 2 n (Cu 2 O)…”

“…16,36 BTAH passivation and hexavalent chromium passivation do not change the corrosion process of copper coating, but the formation of a passivation lm on the surface can effectively isolate the copper coating from the solution, thereby reducing the corrosion rate of the coating. 1,11,[15][16][17]30 Moreover, the coverage of a single BTAH passivation lm is not complete, and the isolation effect is signicantly worse than that of the hexavalent chromium passivation lm. For MBT-passivated copper coatings, the appearance of inductive arc may be related to the corrosion inhibition mechanism of MBT.…”

“…Studies determined that potassium sorbate, OP-10, molybdate and phosphate all showed good synergistic effects with BTAH. [14][15][16][17][18] BTAH alone protects copper from corrosion in sulfate solutions only in the potential range below 0.4 V (vs. SCE), but a mixture of potassium 2,4-hexadienoate and BTAH provides complementary and robust corrosion protection for copper over a wide potential range. 14 The combination of BTAH and molybdate promotes the formation of BTAH passivation lm on copper, and shows better corrosion inhibition performance than single BTAH.…”

Crack resistance of a noble green hydrophobic antimicrobial sealing coating film against environmental corrosion applied on the steel–cement interface for power insulators

“…The insulator hardware (pin) naturally interacts with oxygen in a very alkaline (pH 13) environment formed by cement hydration surrounding it, forming a thin oxide passive layer on its surface that functions as a physical barrier against corrosion. [1][2][3] Admittedly, in harsh environments such as airborne sea spray, sea storms, acid rain, and corrosion-inducing microbes, the passivating lm formed on the insulator steel (pin) that protects the steel (pin) from corrosion may be lost due to Cl À ion diffusion and pH, resulting in accelerated corrosion. Furthermore, CO 2 and H 2 O can penetrate the cement via pores and react with Ca(OH) 2 to produce CaCO 3 and H 2 O 2 , resulting in a pH reduction in the concrete pore solution.…”