ASTM B480-88(2001)
(Guide)Standard Guide for Preparation of Magnesium and Magnesium Alloys for Electroplating
Standard Guide for Preparation of Magnesium and Magnesium Alloys for Electroplating
SCOPE
1.1 This guide describes two processes used for plating on magnesium and magnesium alloys: direct electroless nickel plating and zinc immersion. Some users report that the direct electroless nickel procedure does not produce quite as high a level of adhesion as zinc immersion.
1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 5.1.1 and 5.2.9.2.
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Designation:B480–88(Reapproved 2001)
Standard Guide for
Preparation of Magnesium and Magnesium Alloys for
1
Electroplating
This standard is issued under the fixed designation B 480; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4.2 Purity of Water—All water used for solutions, whether
new or recycled, should be monitored for cations, anions, and
1.1 This guide describes two processes used for plating on
organic matter that are known to interfere with the plating
magnesium and magnesium alloys: direct electroless nickel
process.
plating and zinc immersion. Some users report that the direct
electroless nickel procedure does not produce quite as high a
5. Processes
level of adhesion as zinc immersion.
5.1 Procedures:
1.2 This standard does not purport to address all of the
5.1.1 Wheel polish and buff parts for smooth, highly pol-
safety concerns, if any, associated with its use. It is the
ished surfaces.Tumble and burnish small parts.Acid pickle the
responsibility of the user of this standard to establish appro-
parts after use of wire brushing or steel wool. (Warning—
priate safety and health practices and determine the applica-
Because of the high flammability of powdered magnesium,
bility of regulatory limitations prior to use. For specific hazard
special precautions against fire are important. Polishing and
statements, see 5.1.1 and 5.2.9.2.
buffing lathes should be kept scrupulously clean. Dust from
2. Referenced Documents grinding in and around lathes should be swept up and placed in
closed containers for proper disposal. Exhaust systems should
2.1 ASTM Standards:
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be cleaned frequently and the residues handled similarly. If
B 322 Practice for Cleaning Metals Prior to Electroplating
abrasives are used in tumble finishing, similar precautionary
3. Significance and Use
techniques should be used for the solids from the abrasive
slurry.)
3.1 Metals are electroplated on magnesium for various
5.1.2 Chemical—Remove oil and grease in an alkaline soak
purposes: solderability, RF grounding, hermetic sealing, wear
cleaner. Remove other soils and coatings in suitable acid
resistance, corrosion resistance, appearance, and electrical
pickling solutions.
conductivity, for example. Because magnesium is covered with
a naturally occurring oxide film, usual procedures for the
NOTE 1—General information on the cleaning of metals is given in
preparation of metals for autocatalytic or electrolytic plating
Practice B 322.
cannot be used.
5.2 General Electroplating Procedure:
5.2.1 Remove oil, grease, and other soils left from preplat-
4. Reagents
ing procedures by soak cleaning in an alkaline cleaner suitable
4.1 Purity of Reagents—All acids and chemicals used in
for magnesium.
this guide are of technical grade. Acid and base solutions are
5.2.2 Rinse in cold water.
based on the following assay materials:
NOTE 2—As generally used in rinsing terminology, cold water refers to
Ammonium hydroxide (NH OH) 30 mass %, density 0.895 g/L
4
water from an unheated water supply as opposed to heated water used for
Nitric acid (HNO ) 67 mass %, density 1.16 g/L
3
Sulfuric acid (H SO ) 93 mass %, density 1.40 g/L drying or other purposes. In some areas, particularly in water, ambient
2 4
Hydrofluoric acid (HF) 70 mass %, density 1.258 g/L
water temperatures may be too low for effective rinsing. In those
Phosphoric acid (H PO ) 85 mass %, density 1.689 g/L
3 4
instances, the rinse water may need to be heated.Aminimum temperature
of 16°C is recommended for effective rinsing.
5.2.3 Electroclean parts in an alkaline electrocleaner suit-
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This practice is under the jurisdiction of ASTM Committee B08 on Metallic
ableformagnesium.Makethemagnesiumcathodicat7.5to13
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 on
2
A/dm and 85°C.
Pretreatment.
Current edition approved March 25, 1988. Published May 1988. Originally
5.2.4 Rinse in cold water.
e
1
published as B 480 – 68. Last previous edition B 480 – 68 (1980) .
5.2.5 Pickle in one of the following solutions:
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Annual Book of ASTM Standards, Vol 02.05.
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B480–88 (2001)
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5.2.5.1 Ferric Nitrate Pickle: 5.2.10 Rinse thoroughly in cold water.
Chromic acid (CrO ) 180 g/L
3
NOTE 6—For alloys M1660, M13120, M13312, or M13310, a double
Ferric nitrate (Fe(NO )·9H O) 40 g/L
3 2
zinc immersion is required. After step 5.2.10, steps 5.2.7-5.2.10 are
Potassium fluoride (KF) 3.5 g/L
repeated follow
...
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