ANSI EIA-977-2017 pdf free download – Test Method – Electronic Passive Components Exposure to Atmospheric Sulfur.|
This standard defines options for testing passive electronic components for susceptibility tothe effects of environmental sulfur. Such susceptibility results in the corrosion of silver inthe presence of sulfur compounds in a liquid or gaseous state, potentially leading to component failure.
2.REFERENCED DOCUMENTS
The current revision of the referenced documents in effect at the date of agreement to the testplan shall be used. Subsequent test plans will automatically use the latest revision of thesereferenced documents.
2.1. ASTM B 809: Standard Test Method for Porosity in Metallic Coatings by Humid Sulfur Vapor (“Flowers of Sulfur”‘).
3. APPARATUS AND MATERIALS
3.1. Test Specimen – The component to be tested, typically surface mount resistors or other passive components containing silver.
3.2. Control Sample- A silver coupon to be suspended in the test container by means of a non-corroding material such as nylon line.This control sample is used to confirm thepresence of a sulfur vapor in the test container.
3.3. Dish – A Petri or other shallow dish approximately 15 cm (6 in) in diameter to hold powdered sulfur. If a large test vessel is used and the silver control coupon does notblacken (tarnish) from exposure to sulfur within 24 hours, a larger diameter shallowcontainer may be needed to accommodate additional sulfur.
3.4. Reagent – Sulfur, Sublimed (“Flowers-of-Sulfur”) powder, CAS No.7704-34-9,N.F.
or laboratory grade.
3.4.1. Sulfur placement in Petri dish – A layer of sulfur approximately 10 mm (approx. 0.39 in) thick shall be placed in the Petri dish such that it covers the entire bottomsurface of the container.
3.4.2. Reuse of reagent – It is recommended that the sulfur be replaced with fresh
material each test; however, the reagent may potentially be used for multiple testsby using the corrosion of the silver control specimen as an indicator that the reagent must be replaced. If the control specimen does not blacken (tarnish) from sulfur exposure within 24 hours (per the definition in Section 4.5), the reagent must be replaced.
3.5. Test Container – Any conveniently-sized vessel of glass, polycarbonate, stainless steel (or any other material) that is not affected by sulfur vapor and elevated temperatures may be used as the test container. The size of the test samples will dictate the required size of the container. For small components such as chip resistors, a glass desiccator of 9 to 10L capacity will be sufficient. The vessel does not need to be hermetically sealed and may have a small vent opening (1 to 4 mm diameter hole) to allow equalization of pressure when elevated temperatures are present.
3.5.1. Large test containers – Larger vessels may be required to accommodate test boards and Printed Circuit Board Assemblies (PCAs). If a large test container is used and the silver coupon does not blacken (tarnish) from sulfur exposure within 24 hours (per the definition in Section 4.5), a larger diameter Petri dish and additional sulfur may be needed (Sections 5.1 and 5.2).
3.6 Convection Oven or Hot Plate– A convection oven or hot plate may be used to maintain the required temperature inside the test container.
3.7 Thermocouples – Thermocouples are used to monitor and control the temperature inside the test container.
3.8 Electrical Measurement Test Setup – A resistance bridge or multi-meter and appropriate test probes capable of providing component electrical measurements within specified tolerances. This setup shall apply 5% of the component’s primary rating up to 50mW maximum (e.g., power for resistors, voltage for capacitors, current for inductors, etc.).
3.9 Microscope – An optical microscope capable of up to 50X magnification.ANSI EIA-977 pdf download.