ASTM B733-21
Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal

Standard No.

ASTM B733-21

Release Date

2021

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM B733-22

Latest

ASTM B733-22

Scope

1.1 This specification covers requirements for autocatalytic (electroless) nickel-phosphorus coatings applied from aqueous solutions to metallic products for engineering (functional) uses. 1.2 The coatings are alloys of nickel and phosphorus produced by autocatalytic chemical reduction with hypophosphite. Because the deposited nickel alloy is a catalyst for the reaction, the process is self-sustaining. The chemical and physical properties of the deposit vary primarily with its phosphorus content and subsequent heat treatment. The chemical makeup of the plating solution and the use of the solution can affect the porosity and corrosion resistance of the deposit. For more details, see ASTM STP 265 (1)2 and Refs (2), (3), (4), and (5). 1.3 The coatings are generally deposited from acidic solutions operating at elevated temperatures. 1.4 The process produces coatings of uniform thickness on irregularly shaped parts, provided the plating solution circulates freely over their surfaces. 1.5 The coatings have multifunctional properties, such as hardness, heat hardenability, abrasion, wear and corrosion resistance, magnetics, electrical conductivity provide diffusion barrier, and solderability. They are also used for the salvage of worn or mismachined parts. 1.6 The low phosphorus (2 to 4 % P) coatings are microcrystalline and possess high as-plated hardness (620 to 750 HK 100). These coatings are used in applications requiring abrasion and wear resistance. 1.7 Lower phosphorus deposits in the range between 1 % and 3 % phosphorus are also microcrystalline. These coatings are used in electronic applications providing solderability, bondability, increased electrical conductivity, and resistance to strong alkali solutions. 1.8 The medium phosphorous coatings (5 to 9 % P) are most widely used to meet the general purpose requirements of wear and corrosion resistance. 1.9 The high phosphorous (more than 10 % P) coatings have superior salt-spray and acid resistance in a wide range of applications. They are used on beryllium and titanium parts for low stress properties. Coatings with phosphorus contents greater than 11.2 % P are not considered to be ferromagnetic. 1.10 Units—The values stated in SI units are to be regarded as standard. 1.11 The following precautionary statement pertains only to the test method portion, Section 9, of this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.12 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

ASTM B733-21 Referenced Document

• ANSI/ASQ Z1.4 Sampling Procedures and Tables for Inspection by Attributes
• ASTM B368 Standard Method for Copper-Accelerated Acetic Acid-Salt Spray (Fog) Testing (CASS Test)
• ASTM B374 Standard Terminology Relating to Electroplating
• ASTM B380 Standard Test Method for Corrosion Testing of Decorative Electrodeposited Coatings by the Corrodkote Procedure
• ASTM B487 Standard Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section
• ASTM B499 Standard Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Nonmagnetic Coatings on Magnetic Basis Metals
• ASTM B504 Standard Test Method for Measurement of Thickness of Metallic Coatings by the Coulometric Method
• ASTM B537 Standard Practice for Rating of Electroplated Panels Subjected to Atmospheric Exposure
• ASTM B567 Standard Test Method for Measurement of Coating Thickness by the Beta Backscatter Method
• ASTM B568 Standard Test Method for Measurement of Coating Thickness by X-Ray Spectrometry
• ASTM B571 Standard Practice for Qualitative Adhesion Testing of Metallic Coatings
• ASTM B578 Standard Test Method for Microhardness of Electroplated Coatings
• ASTM B602 Standard Test Method for Attribute Sampling of Metallic and Inorganic Coatings
• ASTM B667 Standard Practice for Construction and Use of a Probe for Measuring Electrical Contact Resistance
• ASTM B678 Standard Test Method for Solderability of Metallic-Coated Products
• ASTM B697 Standard Guide for Selection of Sampling Plans for Inspection of Electrodeposited Metallic and Inorganic Coatings
• ASTM B762 Standard Test Method of Variables Sampling of Metallic and Inorganic Coatings
• ASTM B849 Standard Specification for Pre-Treatments of Iron or Steel for Reducing Risk of Hydrogen Embrittlement
• ASTM B850 Standard Guide for Post-Coating Treatments of Steel for Reducing the Risk of Hydrogen Embrittlement
• ASTM B851 Standard Specification for Automated Controlled Shot Peening of Metallic Articles Prior to Nickel, Autocatalytic Nickel, or Chromium Plating, or as Final Finish
• ASTM D1193 Standard Specification for Reagent Water
• ASTM D2670 Standard Test Method for Measuring Wear Properties of Fluid Lubricants (Falex Pin and Vee Block Method)
• ASTM D2714 Standard Test Method for Calibration and Operation of the Falex Block-on-Ring Friction and Wear Testing Machine
• ASTM D3951 Standard Practice for Commercial Packaging
• ASTM D4060 Standard Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser
• ASTM E140 Standard Hardness Conversion Tables for Metals Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Superficial Hardness, Knoop Hardness, and Scleroscope Hardness
• ASTM E156 
• ASTM E352 Standard Test Methods for Chemical Analysis of Tool Steels and Other Similar Medium- and High-Alloy Steels
• ASTM E60 Standard Practice for Analysis of Metals, Ores, and Related Materials by Molecular Absorption Spectrometry
• ASTM F519 Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating Processes and Service Environments
• ASTM G31 Standard Practice for Laboratory Immersion Corrosion Testing of Metals
• ASTM G5 Standard Reference Test Method for Making Potentiostatic and Potentiodynamic Anodic Polarization Measurements
• ASTM G59 Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements
• ASTM G85 Standard Practice for Modified Salt Spray (Fog) Testing
• ISO 4527 Metallic coatings - Autocatalytic (electroless) nickel-phosphorus alloy coatings - Specification and test methods
• SAE AMS2430 SHOT PEENING
• SAE AMS2590 Rotary Flap Peening of Metal Parts

ASTM B733-21 history

• 2022 ASTM B733-22 Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal
• 2021 ASTM B733-21 Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal
• 2015 ASTM B733-15 Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal
• 2014 ASTM B733-04(2014) Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal
• 2004 ASTM B733-04(2009) Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal
• 2004 ASTM B733-04 Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal
• 1997 ASTM B733-97 Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal
• 1984 ASTM B733-84 Standard Specification for Autocatalytic Nickel-Phosphorus Coatings on Metals