Anisole added to the bath mixture improves Brenner aluminum plating bath technique. Mixture has lower bath vapor-pressure and the electro-deposits obtained have greater physical strength than deposits from the Brenner bath

Lui, K.

English

NASA Technical Reports Server

December 1969	 Brief 69-10737 
NASA TECH BRIEF 
NASA Teèh Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Mixed Ether Bath for Electrodeposition of Aluminum 
A description is given of an improvement in the 
Brenner aluminum plating bath technique based on 
the addition of anisole to the bath mixture. This 
improved mixture has a lower bath vapor pressure 
and the electro-deposits obtained from this mixture 
have greater physical strength than deposits from the 
Brenner bath. The mixed ether bath consists of: 
Anisole to ethyl ether (volume ratio) 1:2 
Aluminum Chloride (Molar concentration) 3.4M 
Lithium aluminum hydride (Molar concentration) 
0.3-0.4 M 
However, the operation of the aluminum plating 
bath is very hazardous because of the ether content 
and the bath reaction with oxygen, carbon dioxide, 
and moisture. Consequently, the operations of the 
plating bath are conducted in a dry nitrogen atmos-
phere within a glove box. 
The mixed ether is cooled during the addition of 
anhydrous aluminum chloride (AId 3 ) by an im-
mersed cooling coil through which a coolant is 
circulated. 
The AId 3 is slowly dissolved into the cold mixed 
ether carefully so that the bath temperature does not 
exceed 303°K. If AlCl is added too rapidly, severe 
localized heating occurs which darkens the solution 
and occasionally produces unsatisfactory deposits. 
After the solution is prepared, it remains undisturbed 
for 16 to 24 hours to permit settling of the minute grey 
suspended particles. A medium-porosity fritted-glass
Buchner filter is then used to produce the desired 
crystal clear, light amber solution. 
The complete plating solution is accomplished by 
slowly mixing the AIC13 -mixed ether solution with 
the lithium aluminum hydride (LiA1H 4 )- mixed ether 
solution. This addition of LiA1H 4
 must be carefully 
performed to prevent excessive foaming, temperature 
(kept below 303°K), and localized precipitation. 
The bath is complete when the molar concentration 
of LiA1H 4
 is between 0.3 and 0.4 M in the resultant 
solution and the molar concentration of AlCl3 is 
3.4 M. 
The mixed ether bath for the electrodeposition of 
aluminum may be used to produce various lightweight 
structures, pressure vessels, or cryogenic tank liners. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Langley Research Center 
Langley Station 
Hampton, Virginia 23365 
Reference: TSP69-10737 
Patent status: 
No patent action is contemplated by NASA. 
Source: Kenneth Lui of 
Electro-Optical Systems, Inc. 
under contract to 
Langley Research Center 
(LA R- 10200) 
Category 03 
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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Mixed ether bath for electrodeposition of aluminum

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