ASTM B877-96(2013)
Standard Test Method for Gross Defects and Mechanical Damage in Metallic Coatings by the Phosphomolybdic Acid (PMA) Method

Standard No.

ASTM B877-96(2013)

Release Date

1996

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM B877-96(2018)

Latest

ASTM B877-96(2018)

Scope

5.1 The primary purpose of the PMA test is to determine the presence of mechanical damage, wear through, and other gross defects in the coating. Most metallic coatings are intended to be protective, and the presence of gross defects indicates a serious reduction of such protection.

5.2 The protection afforded by well applied coatings may be diminished by improper handling following plating or as a result of wear or mechanical damage during testing or while in service. The PMA test can serve to indicate the existence of such damage.

5.3 This test is used to detect underplate and substrate metal exposed through normal wear during relative motions (mating of electrical contacts) or through mechanical damage. As such, it is a sensitive pass/fail test and, if properly performed, will rapidly detect wear through to base metals or scratches that enter the base metal layers.

5.4 This test is relatively insensitive to small pores. It is not designed to be a general porosity test and shall not be used as such. The detection of pores will depend upon their sizes and the length of time that the reagent remains a liquid.

5.5 This test cannot distinguish degrees of wear through or whether the wear through is to nickel or copper. Once base metal is exposed, the colored molybdenum complex is formed. While relatively small area defects (compared to the area of the droplet) may be seen at the bottom of the drop as tiny colored regions immediately after applying the PMA, any larger areas of exposed base metal will cause the entire droplet to turn dark instantly.

5.6 The PMA test also detects mechanical damage that exposes underplate and substrate metal. Such damage may occur in any postplating operation or even at the end of the plating operation. It can often occur in assembly operations where plated parts are assembled into larger units by mechanical equipment.

5.7 The PMA test identifies the locations of exposed base metal. The extent and location of these exposed areas may or may not be detrimental to performance. The PMA test is not recommended for predictions of product performance, nor is it intended to simulate field failure mechanisms. For such contact performance evaluations, an environmental test known to simulate actual failure mechanisms should be used.

5.8 The PMA test is primarily intended for the evaluation of individual samples rather than large sample lots, since evaluations are normally carried out one at a time under the microscope (see Section 10).

5.9 This test is destructive. Any parts exposed to the PMA test shall not be placed in service.

1.1 This test standard covers equipment and methods for using phosphomolybdic acid (PMA) to detect gross defects and mechanical damage including wear through in metallic coatings of gold, silver, or palladium. These metals comprise the topmost metallic layers over substrates of nickel, copper, or copper alloys.

1.2 Recent reviews of porosity testing, which include those for gross defects, and testing methods can be found in the literature.^{2, 3} An ASTM guide to the selection of porosity and gross defect tests for electrodeposits and related m......

ASTM B877-96(2013) Referenced Document

• ASTM B374 Standard Terminology Relating to Electroplating
• ASTM B488 Standard Specification for Electrodeposited Coatings of Gold for Engineering Uses
• ASTM B542 Standard Terminology Relating to Electrical Contacts and Their Use*， 2019-11-01 Update
• ASTM B679 Standard Specification for Electrodeposited Coatings of Palladium for Engineering Use*， 2021-10-01 Update
• ASTM B689 Standard Specification for Electroplated Engineering Nickel Coatings*， 2023-05-01 Update
• ASTM B735 Standard Test Method for Porosity in Gold Coatings on Metal Substrates by Nitric Acid Vapor
• ASTM B741 Standard Test Method for Porosity In Gold Coatings On Metal Substrates By Paper Electrography
• ASTM B765 Standard Guide for Selection of Porosity Tests for Electrodeposits and Related Metallic Coatings
• ASTM B798 Standard Test Method for Porosity in Gold or Palladium Coatings on Metal Substrates by Gel-Bulk Electrography*， 2020-04-01 Update
• ASTM B799 Standard Test Method for Porosity in Gold and Palladium Coatings by Sulfurous Acid/Sulfur-Dioxide Vapor*， 2020-04-01 Update
• ASTM B809 Standard Test Method for Porosity in Metallic Coatings by Humid Sulfur Vapor ("Flowers-of-Sulfur")*， 2024-04-20 Update
• ASTM B866 Standard Test Method for Gross Defects and Mechanical Damage in Metallic Coatings by Polysulfide Immersion*， 2018-08-01 Update

ASTM B877-96(2013) history

• 2018 ASTM B877-96(2018) Standard Test Method for Gross Defects and Mechanical Damage in Metallic Coatings by the Phosphomolybdic Acid (PMA) Method
• 1996 ASTM B877-96(2013) Standard Test Method for Gross Defects and Mechanical Damage in Metallic Coatings by the Phosphomolybdic Acid (PMA) Method
• 1996 ASTM B877-96(2008) Standard Test Method for Gross Defects and Mechanical Damage in Metallic Coatings by the Phosphomolybdic Acid (PMA) Method
• 1996 ASTM B877-96(2003) Standard Test Method for Gross Defects and Mechanical Damage in Metallic Coatings by the Phosphomolybdic Acid (PMA) Method
• 1996 ASTM B877-96 Standard Test Method for Gross Defects and Mechanical Damage in Metallic Coatings by the Phosphomolybdic Acid (PMA) Method