ASTM B630-88(2001)
(Practice)Standard Practice for Preparation of Chromium for Electroplating with Chromium
Standard Practice for Preparation of Chromium for Electroplating with Chromium
SCOPE
1.1 This practice is intended to serve as a process guide (not as a standard procedure) for producing adherent electrodeposits of chromium on chromium for engineering use.
1.2 Only well-known, generally practical methods using hexavalent chromium plating baths have been included. Some of the newer proprietary chromium plating processes produce chromium plating for which this process is unsuitable. Suppliers of the processes should be consulted.
1.3 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 .
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Designation:B630–88(Reapproved 2001)
Standard Practice for
Preparation of Chromium for Electroplating with Chromium
This standard is issued under the fixed designation B 630; 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 factory deposits on such substrates by careful attention to
details in the pretreatment and electroplating process steps.
1.1 This practice is intended to serve as a process guide (not
4.3 Stripping may be done by several methods, including
asastandardprocedure)forproducingadherentelectrodeposits
proprietary processes or inhibited hydrochloric acid solution
of chromium on chromium for engineering use.
(10 to 20 % by volume), or anodic treatment at 55 to 800A/m
1.2 Only well-known, generally practical methods using
(5 to 75 A/ft ) in a solution of 35 to 50 g/L (5 to 7 oz/gal) of
hexavalent chromium plating baths have been included. Some
sodium hydroxide or 60 to 75 g/L (8 to 10 oz/gal) of sodium
of the newer proprietary chromium plating processes produce
carbonate at 20 to 25°C (70 to 80°F).
chromium plating for which this process is unsuitable. Suppli-
4.4 Process Outline:
ers of the processes should be consulted.
4.4.1 Preclean (see 5.1.1 and 5.1.2),
1.3 This standard does not purport to address all of the
4.4.2 Alkaline electrolytic clean (see 5.1.3),
safety concerns, if any, associated with its use. It is the
4.4.3 Rinse (cold water),
responsibility of the user of this standard to establish appro-
4.4.3.1 Rinse (hot water),
priate safety and health practices and determine the applica-
4.4.3.2 Dry,
bility of regulatory limitations prior to use.
4.4.3.3 Mask (see 5.2),
2. Referenced Documents 4.4.4 Activate (see 5.3),
4.4.5 Chromium electroplate,
2.1 ASTM Standards:
4.4.6 Rinse (cold water),
B 177 Guide for Chromium Electroplating on Steel for
4.4.7 Rinse (hot water), and
Engineering Use
4.4.8 Dry.
3. Significance and Use
5. Procedure
3.1 Electrodepositsofchromiumonchromiumareproduced
5.1 Cleaning—The following cleaning treatments may be
in cases where it is desired to obtain a better performing
used for all conditions and types of electrodeposited chro-
coating, to reclaim plated parts that are defective, or restore
mium. The choice of the procedures will be governed largely
worn chromium coatings to original dimensions.
by the condition of the surface.
4. Preparation of Surface
5.1.1 Precleaning—When considerable amounts of grease
and oil are present on the surface, precleaning (emulsion or
4.1 Surface Finishing—The smoothness of the chromium
alkaline spray or soak) is necessary to remove the bulk of the
coating before electroplating with chromium should closely
soil.
approximate the requirements of the finished part. It is usually
5.1.2 Abrasive Cleaning—Oxide and other films may be
achieved by appropriate grinding with a diamond wheel.
removedbymechanicaltechniquesusingsuchabrasivesasfine
4.2 Stripping and Basis Metal—With previously electro-
emery on a cloth or a wheel, pumice slurry, or greaseless
plated parts where the chromium deposit has been worn
buffing compounds. Grit blasting, shot blasting, wet blasting,
through, or where grinding has exposed the basis metal,
or vapor honing may also be used. Abrasive cleaning is
preferred results are obtained by stripping the remaining
generally not necessary when suitable mechanical finishing
chromium completely. However, it is possible to obtain satis-
procedures have been used.
5.1.3 Cathodic Alkaline Cleaning—Removal of final traces
of dirt, grease, and oil is best accomplished by cathodic
This practice is under the jurisdiction of ASTM Committee B08 on Metallic
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 on
alkaline cleaning. Cathodic electrocleaning is necessary be-
Pretreatment.
cause anodic electrocleaning will strip chromium and may
Current edition approved Aug. 26, 1988. Published N
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