Where the
world gathers for metal finishing
Q&As since 1989


-----

Corrosion problem with nickel-chrome plated bumpers

April 29, 2009

We are a company that chrome plate truck bumpers and the following problem just came to us:

We have 5 bumpers with guarantee claim for red corrosion presence. The specification for these bumpers is 66 hr in CASS and a minimum of 37 microns of nickel.

Here is a table of the thicknesses of the corroded bumpers.

Thickness
	Bumper 1	Bumper 2
Semi-Bright nickel	23.53 micron	48.70 micron
High Sulfur nickel	2.50	3.00
Bright nickel	7.05	19.00
Semi-Bright nickel	8.32
High Sulfur nickel	2.00
Bright nickel	6.10
Semi-Bright nickel	4.30
High Sulfur nickel	2.00
Bright nickel	4.81
Semi-Bright nickel	1.0
Bright nickel	2.03
Microporus nickel	1.00	1.00
Chromium	0.25	0.25
TOTAL NICKEL	64.70	71.70

Because the appearance my client needs that some of the bumpers were re-processed some times to eliminate any damage in the finish. The re-process consist in: after plated if the bumper have anything that needs to be eliminated, we buff the entire bumper a little bit and deposit all the nickels and chrome again, this generate several layers of Ni over Ni.

We run CASS test of one of this bumpers and it passed the 66 hrs.

Does someone know why these bumpers were corroded? They only have been in the street for some months; all the guarantee claims came from the same region in Montreal.

Francisco Hornelas
Manager of a plating factory - Mexico, Estado de Mexico, Mexico

---

DEAR FRANCISCO,
TRY ELECTROLESS NICKEL AT LEAST 15 MICRONS PRIOR TO SEMI- BRIGHT NICKEL

SUNIL GADHIA
- RAJKOT, GUJARAT, INDIA
May 5, 2009

---

My dear friend:

Prior to give you any suggestion we need to know your Step test results between Semi Bright and High Sulfur, High Sulfur and Bright, and Bright and Microporous. And the microporosity.

Hector Sanchez
- Guadalajara, Mexico
May 19, 2009