Electroless Ni coatings used in 4% NaCl corrosion control of mild steel
- Univ. del Zulia, Maracaibo (Venezuela). Centro de Estudios de Corrosion
- Univ. Nacional de La Plata (Argentina). Inst. de Investigaciones Fisicoquimicas Teoricas y Aplicadas
The purpose of this work is to study the behavior of electroless Ni coatings on SAE 1020 steel in aqueous 4% NaCl solution. An aqueous solution with NiSO{sub 4}.6H{sub 2}O (Nickel Sulfate), NaH{sub 2}PO{sub 2}.2H{sub 2}O (Sodium Hypophosphite), C{sub 3}H{sub 6}O{sub 3} (Lactic Acid), C{sub 3}H{sub 6}O{sub 2} (Propionic Acid) and Pb(NO{sub 3}){sub 2} (Lead Nitrate) as the basic ingredients of the bath was selected for the autocatalytic deposition of Ni, with an average deposit rate of c.a. 19 {micro}m/h. Steel coupons were immersed in the bath for 1, 2, 3 h in the original solution, renewing with fresh solution every hour. Once coated with nickel, the coupons were subjected to heat treatment for 1, 2, and 3 h at 400 C, measuring hardness to determine how it is affected by thermal treatment. Salt-spray tests were carried out at 30 C in line with ASTM B117-75 and DIN 50907 standards. The corrosion rate was determined by potentiodynamic polarizing curves (0.28.10{sup {minus}3} V/s), using a 4.0% w/w NaCl solution. Corrosion resistance was higher in the coupons that underwent 2--3 h of heat treatment and 2--3 h plating time. Corrosion rate varied between 2.41 and 3.40 {micro}m/y. The surface of the coupons in the salt spray chamber had a good appearance at the end of the 568-hour test.
- OSTI ID:
- 549898
- Report Number(s):
- CONF-970332-; TRN: IM9752%%121
- Resource Relation:
- Conference: Corrosion 97. 52. annual corrosion conference of the National Association of Corrosion Engineers: economics and performance - bridging the gap and NACExpo, New Orleans, LA (United States), 9-14 Mar 1997; Other Information: PBD: 1997; Related Information: Is Part Of Corrosion/97 conference papers; PB: [4584] p.
- Country of Publication:
- United States
- Language:
- English
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