Effect of hydrazine and hydroxylaminophosphate on chrome plating from trivalent electrolytes

• Published in: Applied surface science Vol. 253; no. 16; pp. 6738 - 6743
• Main Authors: SURVILIENE, S, JASULAITIENE, V, NIVINSKIENE, O, CESUNIENE, A
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 15.06.2007
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electrodeposition, electroplating; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Atomic force microscopy; FT-IR; Infrared spectra; Hardness; Film growth; Surface structure; Urea; Lifetime; Transition elements; Chromium; Fine grain structure; Electrodeposition; Formates; Formate; XPS; Hydrazine; Hydroxylaminophosphate; X-ray photoelectron spectra
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.01.122

The influence of hydrazine and hydroxylaminophosphate on solution chemistry and quality of chromium coatings deposited from Cr(III) formate-urea baths has been studied by FT-IR, XPS and AFM. The results have shown that hydrazine and hydroxylaminophosphate differently affect Cr plating. The morphology of Cr deposits obtained in the formate-urea electrolytes is a typical nodular structure with a less nodular and smoother fine-grained structure of Cr obtained in the presence of hydroxylaminophosphate. Hydrazine, in contrast, worsened the quality and lowered the hardness of the deposits. The current efficiency of chromium increases in the presence of both hydrazine and hydroxylaminophosphate. This may be related with the ability of these ligands to reduce the CrH content in the growing Cr deposit. The data obtained suggest that hydroxylaminophosphate improves the stability of the active [Cr(carbamide) sub(n)(H sub(2)O) sub(6) sub(-) sub(n)] super(3) complexes providing good quality of the deposits and prolonged working lifetime in the formate-urea bath.