Activation process forms adherent electrodeposits of copper, nickel, and chromium on titanium alloy. Good adhesion of electroplated deposits is obtained by using acetic-hydrofluoric acid anodic activation process

Lowery, J. R.

English

NASA Technical Reports Server

September 1971	 Brief 71-10338 
.
NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
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be directed to the Technology. Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Electroplating on Titanium Alloy 
fl
An activation process can form adherent electro-
deposits of copper, nickel, and chromium on 
titanium alloy. .Electrodeposition is one of the most 
common methods of coating titanium with other 
metals, but it has serious shortcomings. Conventional 
electroplating can produce a coating on titanium, 
but there is a distinct lack of adhesion. Studies 
have indicated that poor adhesion is caused by the 
formation of an extremely tenacious oxide film 
after the metal is exposed to the atmosphere. It is 
mandatory that this film either be removed long 
enough to permit an initial electrodeposit to be made, 
or be replaced by some other film that will not 
limit adhesion. Test specimens were cleaned by vapor 
degreasing in perchlorethylene and then soaking 
for 10 to 20 minutes in a proprietary alkali. Good 
adhesion of electroplated deposits was obtained by 
using an acetic-hydrofluoric acid anodic activation 
process. 
An alloy composed of titanium, 6% aluminum, 
and 4% vanadium (Ti-6A1-4V) was tested with chro-
mium, nickel, electroless nickel, and copper. Results 
indicated that more adherent coatings could be 
produced with copper. Several copper plating baths 
were used, including a commercial potassium 
cyanide copper-plating formulation, an acid copper 
sulfate bath, and a copper fluoborate bath. Nickel 
was plated from a Watts-type bath, and chromium 
from a standard chromic acid sulfate bath. 
Plated specimens, 10 cm (4.0 in.) long, 1.3 cm 
(0.5 in.) wide, 0.16 cm (0.062 in.) thick, were 
evaluated on the basis of standard qualitative ad-
hesion tests. The specimens were bent repeatedly 
through an angle of 3.1 rad (180) until fracture of 
the basic metal occurred. After fracture, attempts 
were made to detach the plating from the basic metal 
with a sharp instrument. In cases of very poor adhesion, 
the plating separated in large flakes or pulled off 
easily. 
Since titanium alloys are known to be susceptible 
to damage from hydrogen evolved during metal 
finishing operations, tests were conducted to detect 
possible hydrogen embrittlement in treated speci-
mens. The tests included detecting changes in 
notch-sensitivity at room temperature and at low 
temperatures on samples subjected to various pre-
plating and plating processes. Some controlled 
bend tests and chemical analyses were also made 
to verify the effects of hydrogen. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Code A&TS-TU 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B71-10338 
Patent status: 
No patent action is contemplated by NASA. 
Source: J. R. Lowery
Marshall Space Flight Center

(MFS-21251) 
Category 08 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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Electroplating on titanium alloy

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