Parts are rack or barrel plated to ASTM B standard thicknesses from ” to “, depending on the base metal and application. Pure % tin is. Designation: B – 97 (Reapproved )e1 Standard Speci?cation for Electrodeposited Coatings of Tin1 This standard is issued under the. ASTM B Standard Specification for Electrodeposited Coatings of Tin.
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Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
MIL-T-10727 vs. ASTM B545
Coatings shall be sampled, tested and conform accordingly to specified requirements as to appearance, purity, local and mean thickness, integrity including gross defects, mechanical damage, and porosityadhesion, solderability, and hydrogen sstm relief. Applications are as follows: Other coatings variations, such as surface appearance type 4. The size of the sample and the criteria of compliance are determined by the application of statistics.
The thickness of such an undercoating is usually greater than 0.
Where a contact mark is inevitable, its location shall be subject to agreement between the supplier and the purchaser. In this specialized application, the occurrence of whisker growth is aastm frequent to be an obstacle to the use of tin.
Poor adhesion will be shown if the coating blisters, cracks, or peels. Typical Applications Mild service conditions, particularly where the signi? Rejection shall be reported to the seller promptly and in writing. Parts coated with tin can be assembled safely in contact with iron and steel, tin-coated aluminum, yellow chromated zinc, cadmium, and solder coatings.
If special test specimens are used 7. Addition of the sulfuric acid may be made before the test specimens are placed in position, provided that the cabinet is closed within 5 min of addition of the acid. The amount of porosity in the coating that may be tolerable depends on the severity of the environment that g545 article is likely to encounter during service or storage.
With such thin coatings, a diffusion barrier of nickel may be advantageous, although users should also consider the use of thicker coatings when solderability must be maintained over a period of years 6. When necessary, preliminary samples showing the? Although the tin surface will remain bright for long periods in the absence of moisture, this invisible surface oxide layer is not truly protective.
Some examples are given in Appendix X6. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date. Evidence of diffusion is the formation of a layer of copper-tin intermetallic at the interface and diffusion of zinc to the surface if the substrate is brass. This standard has been approved for use by agencies of the Department of Defense.
This abstract is a brief summary of the referenced standard. They shall not be stained or discolored. All surfaces shall be substantially free of grease or oil used in the? Also found on baking pans after re?
ASTM B – Tin Plating by Keystone Finishing
Very severe service conditions, including elevated temperatures, where underlying metal diffusion and intermetallic formation processes are accelerated. Such acceptance asgm pass-fail criteria, if required, should be part of the product speci?
The coating should adhere to the basis metal when subjected to the agreed test;? Practically all of the following methods take into account the chief cause of tin whiskering, which is the presence of stresses in the tin coating 8: The shape of the part is also a factor;? Therefore, in designing for low-voltage electronic equipment where components are closely spaced, tin coatings should either not be aetm, or whisker formation should be inhibited or prevented by the application of prevention methods.
Visual examination, time of wetting, measurement of area of spread, and calculation of spread values are used to assess solderability 1, 2. In normal indoor exposure, tin is protective on iron, steel, nickel, copper, and their alloys. The surface appearance types are matte tin electrodeposits, bright tin electrodeposits, and flow-brightened electrodeposits.
If the sulfur dioxide concentration in the atmosphere is too high, the corrosion product formed is too? Three test methods are described in Appendix X3, while a simple dip test is given in Test Method B Flow-brightened coatings shall be free of dewetted areas and beads. This specification covers the requirements for electrodeposited tin coatings applied to metallic articles to provide a low contact resistance surface, to protect against corrosion, to facilitate soldering, to provide anti-galling properties, and to be a stop-off coating in the nitriding of high-strength steels.
Suspend the test specimens above this solution on nonmetallic supports, with the surfaces of the specimens not less than 25 mm 1 in. In cases of rejection, the seller may make a claim for a rehearing. Maintain pressure sufficient to burnish the?
Examination of 43 magni? Corrosion can be expected at discontinuities in the coating such as pores due to galvanic couples formed between the tin and the underlying metal through the discontinuities, especially in humid atmospheres.
They shall be adherent and visually free of blisters, pits, peeled areas, cracks, nodules, and unplated areas. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided astj part of the standard. However, some of these platings cannot be used in contact with food. Test Method B contains several plans and also provides instructions for b45 plans to meet special needs.
Examples are electrical hardware such as cases for aetm and coils, transformer cans, screened cages, chassis, frames, and? The test piece is held in a clamp that extends from an arm directly over the solder bath. Practice B may be consulted to determine the most appropriate test method.