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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In many applications for tin coatings, whisker growth has not been a problem, but there are critical applications X6. The maximum thickness for?
An underplating of nickel or copper must be used as a diffusion barrier on brass. However, some of these platings cannot be used in contact with food.
Add to the sodium thiosulfate solution a volume of 0. 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. Severe service, including exposure to dampness and mild corrosion from moderate aztm environments.
Thicker coatings are used for water containers, threaded steel couplings of oil drilling strings, and seacoast atmospheres.
Some tin coatings, especially of bright tin, may show? In normal indoor exposure, tin is protective on iron, steel, nickel, copper, and their alloys.
The number of articles shall be sufficient to have a total weight b5445 coating of at least 0. Therefore, in designing for low-voltage electronic equipment asstm components are closely spaced, tin coatings should either not be used, or whisker formation should be inhibited or prevented by the application of prevention methods.
The values given in parentheses are for information only.
MIL-T-10727 vs. ASTM B545
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. This is in contrast to strikes or? Flow-brightened coatings shall be free of dewetted areas and beads.
Test Method B contains several plans and also provides asttm for calculating plans to meet special needs. Examples are electrical b455 such as cases for relays and coils, transformer cans, screened cages, chassis, frames, and? Black spots or lines are evidence of mechanical damage or gross defects. Suspend the test specimens above this solution on nonmetallic supports, with the surfaces of the specimens not less than 25 mm 1 in.
After removing the specimens from the corrosive atmosphere, allow them to dry without wiping or cleaning in any way, and then examine them using the options outlined in Guide B bb545, Sections 6 and 7. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Coatings shall be grouped into six service classes, which is based on the minimum thickness and severity of service required for the coating, and three surface appearance types, which is based on the type electroplating process employed.
Very severe service conditions, including elevated temperatures, where underlying metal bb545 and intermetallic formation processes are accelerated. 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.
Porosity increases as the coating thickness decreases, so that minimum thicknesses must be speci? Initial scanning should be conducted for all elements in order to detect any unknown or atm impurities. They shall be adherent and visually free of blisters, aastm, peeled areas, cracks, nodules, and unplated areas.
ASTM B – standard specification for electrodeposited coatings of tin_百度文库
If the sulfur dioxide concentration in the atmosphere is too high, the corrosion product formed is too? It gradually thickens, and it may eventually produce a dull gray appearance. A suitable burnishing implement is a copper or steel disk used edgewise and broadside. Applications are as follows: Some examples are given in Appendix X6.
The goal is to de? A superscript epsilon e indicates an editorial change since the last revision or reapproval. Calculate the coated area in mm2 to an accuracy of at least 1 part in 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.
There needs to be sufficient aztm tin below asfm oxide layer in order for this to occur, because the intermetallic compounds formed from tin and the basis metal will not react in this way 7. Remove the articles, rinse them in clean water, wipe and brush as necessary to remove smut antimony residuesand dry. Where a contact mark is inevitable, its location shall be subject to agreement between the supplier and the purchaser.
Coatings shall be sampled, tested and conform accordingly to specified requirements as b45 appearance, purity, local and mean thickness, integrity including gross defects, mechanical damage, and porosityadhesion, solderability, and hydrogen embrittlement relief. Other coatings variations, such as surface appearance type 4.
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. In cases of rejection, the seller may g545 a claim for a rehearing.
Poor adhesion will be shown by the appearance aastm a loose blister that grows as rubbing is continued.
The amount of porosity in the coating that may be tolerable depends on the severity of the environment that the article is likely to encounter during service or storage. Current edition approved April 1,