1、 ATIS-0600009.2007 ROHS-COMPLIANT PLATING STANDARD FOR STRUCTURAL METALS, BUS BARS, AND FASTENERS AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS The Alliance for Telecommunication Industry Solutions (ATIS) is a technical planning and standards development organization that is committed to rapidly
2、 developing and promoting technical and operations standards for the communications and related information technologies industry worldwide using a pragmatic, flexible and open approach. Over 1,100 participants from over 300 communications companies are active in ATIS 22 industry committees and its
3、Incubator Solutions Program. AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. Consensus is established when, in the judgment of the
4、ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effo
5、rt be made towards their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not confo
6、rming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the
7、 name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the Ame
8、rican National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaime
9、r DIRECTIVE 2002/95/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 27 January 2003; aka EU-RoHS.2NOTE - Impending RoHS legislation in China, Korea and state governments within the US may apply similar restrictions, as does EU-RoHS. See . 2 ATIS-0600006.2006 Mechanical Structural Issues.33 ASTM
10、B 921, Standard Specification for Non-Hexavalent Chromium Conversion Coatings on Aluminum and Aluminum Alloys.44 ASTM B 449 921, Standard Specification for Chromates on Aluminum, last re-issued in 1998.45 MIL-DTL-5541F, Chemical Films for Aluminum and Aluminum Alloys.51One comment is worth making ab
11、out pre-plated steel from a RoHS perspective is though zinc-pre-plated material is intrinsically RoHS-compliant, it is sometimes supplied with a chromate finish. When specifying pre-plated material, it is recommended that RoHS requirements be clearly stated. 2See . 3This document is available from t
12、he Alliance for Telecommunications Industry Solutions (ATIS), 1200 G Street N.W., Suite 500, Washington, DC 20005. 4This document is available from the American Society for Testing and Materials (ASTM), 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, Phone: (610) 832-9585, Fax: (610) 832-95
13、55, . ATIS-0600009.2007 3 6 ASTM B 633, Electrodeposited Coatings of Zinc on Iron and Steel.47 ASTM B117, Test Method for Salt Spray (Fog) Testing.48 MIL-DTL-81706F, Conversion Coatings on Metallic Materials-Determination of Mass Per Unit Area-Gravimetric Method.59 JP002, Current Tin Whisker Theory
14、and Mitigation Practices Guideline.610 JIG-101 Joint Industry Material Guide (JIG), Composition Declaration Guide for Electronic Products.711 ASTM B545, Standard Specification for Electrodeposited Coating of Tin.412 ASTM D 610, Standard Test Method for Evaluating Degree of Rusting on Painted Steel S
15、urfaces.413 ASTM F 2329, Specification for Zinc Coating, Hot-Dip, Requirements for Application to Carbon and Alloy Steel Bolts, Screws, Washers, Nuts, and Special Threaded Fasteners.414 EN 15205, Determination of hexavalent chromium in corrosion protection layers Qualitative Analysis.815 ASTM A 961/
16、A 961M REV, A Standard Specification for Common Requirements for Steel Flanges, Forged Fittings, Valves, and Parts for Piping Applications. 3 DEFINITIONS 3.1 Conversion Coating: Chemical layer formed by controlled oxidation of a thin layer of metal (zinc or aluminum) to provide a corrosion-resistant
17、 coating. Also termed a passivation layer, since the oxide layer formed conducts electronically but resists ionic conduction. 3.2 Hexavalent Chromium: CrVI - Chromium in its +6 valence state. This does not include metallic chromium in alloys. CAS number 15930-94-6 and others. 3.3 Material: Made up o
18、f one or more substances (e.g., an alloy is a material, which in turn is made up of a number of defined substances). 3.4 Network Infrastructure Equipment (NIE): Telecommunications equipment owned and operated by service providers (e.g., rack-mounted equipment in a central office or hut) as opposed t
19、o consumer products that might reside at home such as telephones, small modems, and small routers. 3.5 RoHS: Restriction of Hazardous Substances, the common name for DIRECTIVE 2002/95/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 27 January 2003 on the restriction of the use of certain hazardo
20、us substances in electrical and electronic equipment. 3.6 Passivation Layer: See conversion coating. 3.7 Substance: A chemical element and its compounds (e.g., lead chemical element, lead oxide compound, polyvinyl chloride compound). 5Available from the Department of Defense Single Stock Point for M
21、ilitary Specifications and Standards, located at the Document Automation and Production Service, Building 4/D, 700 Robins Ave, Philadelphia, Pa. 19111-5094. 6This document is available at . 7See . 8See . ATIS-0600009.2007 4 7.8 Threshold level: Concentration level that defines the limit (equal to or
22、) above which the presence of a Substance or Material in a Product. Declared requirements are defined in the Joint Industry Material Guide (JIG) Composition Declaration Guide for Electronic Products. 7.9 Trivalent Chromium: CrIII Chromium in its +3 valence state. 4 COLOR AND AESTHETICS ATIS-0600006.
23、2006, Mechanical Structural Issues, calls for a visual indication of the presence of a finish. For steel-based finishes, using the color designation of blue satisfies this requirement. Term “iridescent” can be used to specify finish either for aluminum or steel. Iridescent is defined here as colors
24、that change with the angle of viewing. Iridescent may be described as clear, but not colorless, insofar as it is visible on the surface of the metal. When the application is thick, colors that vary with the angle of viewing will be visible on rack plated steel sheet. The natural color of CrIII treat
25、ed zinc plate is a clear to iridescent color. Dyes may be added to bath salt formulations to provide a yellow color that mimics the look of CrVI. Iridescent can include the color yellow. Cosmetic requirements are categorized in the workmanship section of this document. CrIII formulations and many NC
26、P formulations are paintable. The compatibility of any particular finish formulation and paint process should be tested to assure the aesthetics and adhesion will endure with age and environment. Workmanship requirements are defined in ATIS-0600006.2006. 5 SHEET METAL END-POINT REQUIREMENTS Notes ar
27、e provided here for discussion of a set of end-point specification for material finishing. All measurements are in metric. 5.1 Carbon Steel ASTM B633 6 classifications should be used to define the durability and characteristics of the zinc plating on a steel substrate. Type II and III should be the
28、standard zinc chromate finishes. Where less than 12-hour salt spray resistance is required, such as plating prior to painting, a non-chromate treatment such as molybdenum or iron phosphate may be specified. Levels of protection measured over 20 years with CrVI conversion coatings (or passivation lay
29、er) are listed under objectives in Table 1 below. Table 1 - Plated Carbon Steel Salt Fog Resistance ASTM B633 Type Requirements Exposure Time (Hours) Objective Exposure Time Goal (Hours) II 96 minimum to white oxide 168 minimum to white oxide III 12 minimum to white oxide 12 minimum to white oxide a
30、nd 48 minimum to red rust ATIS-0600009.2007 5 Table 1 is based on the implicit assumption that white corrosion product is formed prior to red or black corrosion products. Therefore, no corrosion product of any color is allowed prior to the exposure time set forth. The exposure time to red rust, unde
31、r most circumstances, is a function of the thickness of the zinc layer. Zinc layer thickness may be specified by the part designer, when and if it is deemed to be helpful in meeting the corrosion resistance requirements. Rust ratings defined in ASTM D610 12 at the end of the Neutral Salt Spray Test
32、(NSS) may be used to judge product pass/fail. Rust ratings shall be conducted after cleaning the coupon or production sample per ASTM B117, section 13 7. Coating performance at holes, bends, and edges are ignored when determining a rating, as is corrosion accelerated by the run-down from corroded ho
33、les. Table 2 offers a recommended maximum corrosion allowance for test and production samples. More strict criteria may be employed. A production sample is expected to be a random sample part used for on-going quality monitoring. Table 2 - Scale and Description of Rust Ratings Rust Grade Percent of
34、Surface Oxidized after NSS Recommended Coupon pass/fail Recommended Production Sample pass/fail 10 Less than or equal to 0.01 Pass Pass 9 Greater than 0.01% and up to 0.03% Fail Pass 8 Greater than 0.03% and up to 0.1% Fail Conditional pass process improvement needed & Greater than 0.1% and up to 0.
35、3% Fail Fail Type III conversion coatings should be expected to be clear or blue, since they are thinner than comparably protective CrVI coatings. Type II conversion coatings should be iridescent. The finish shall meet the electrical resistance values given in Table 3 below, when measured using the
36、method specified in MIL-DTL-81706F 8 or other similar method. Table 3 - Maximum Electrical Resistances for Finished Zinc on Steel Type Resistance/area Type II .005 ohm/sq Type III .001 ohm/sq An example specification is provided: Zinc Plated: Zinc Plate equivalent to ASTM B633 type II, 5-micron mini
37、mum. Passivation layer must provide 96 hr salt spray minimum to white oxide and 5 milliohms per square inch electrical resistance maximum. Color shall be iridescent. The use of hex valent chromium bath chemistries is prohibited. The last line in the specification prohibiting the use of CrVI is added
38、 to provide assurance that a RoHS-compliant finish will be used, but not to preclude future advances that could provide a non-chromium finish that will meet end point requirements. ATIS-0600009.2007 6 5.2 Aluminum Both ASTM B449-98 and ASTM B961-02 offers three classes for conversion coating for alu
39、minum appropriate for general use in telecom equipment: Class 1: Where only maximum corrosion protection is only desired. Class 2: Where dimensional tolerances are not critial, where corrosion protection is required, and where moderate electrical conduction between mating finished surfaces (due to a
40、pplied pressure) is desired. This finish is typically used as a paint base or for bonding to rubber. Class 3: Where dimensional tolerances are critical, where some corrosion protection is required, and where maximum electrical conduction between mating finished surfaces (due to applied pressure) is
41、desired. For specification purposes, ASTM 961 15 should be used since it calls out non-hexavalent chromium coatings. MIL-DTL-5541F, Chemical Films for Aluminum and Aluminum Alloys 7, type II coatings may also be specified. The finish shall pass ASTM B117 Salt Spray Test requirements for the minimum
42、number of hours listed in Table 4 below: Table 4 - Aluminum Alloy Salt Fog Resistance Time in Hours CLASS Non Heat-Treatable Wrought Alloys Heat Treatable Wrought Alloys 1% Si Class 1 500 336 48 Class 2 250 168 24 Class 3 168 120 12 The finish shall meet the electrical resistance values given in Tab
43、le 5 below, when measured using the method specified in MIL-DTL-81706F or other similar method. Table 5 - Maximum Electrical Resistances for Aluminum Finishes CLASS Resistance/area Class 1 Not Applicable Class 2 .005 ohm/sq Class 3 .001 ohm/sq NOTE - MIL-DTL-81706B1 specifies .005 ohm/sq for class 3
44、. An example specification is provided: Finish shall be chemically oxidized aluminum equivalent to ASTM B921 class 2. Passivation layer must provide 168 hr salt spray minimum to white oxide and 5 milliohms per square inch electrical resistance maximum. Color shall be clear to iridescent. ATIS-060000
45、9.2007 7 6 FASTENERS END-POINT FINISH REQUIREMENTS Where clear-coated fasteners were previously specified, 24 48 hours to red rust and zero time to white corrosion can be achieved with commercial zinc coatings. Use of commercial zinc should be discouraged in favor of zinc with a CrIII overcoat in te
46、lecom applications Fasteners that were previously specified to be yellow chromate may use a 72-hour requirement available in barrel plating with clear/iridescent CrIII. Seventy-two hours minimum to white corrosion product followed by 24-48 hours to red rust shall be specified. Screws in applications
47、 where high torque values are needed may not have a conversion coating or a topcoat over the CrIII coating. Fasteners with exposure to outdoor environments shall be stainless steel, or equivalent material to meet a 30-day salt fog requirement. Hot-dip galvanized materials may be used. When hot-dip g
48、alvanized fasteners are specified, cite ASTM F2329, Specification for Zinc Coating, Hot-Dip, Requirements for Application to Carbon and Alloy Steel Bolts, Screws, Washers, Nuts, and Special Threaded Fasteners 13. 7 SOLDER PLATING SUBSTITUTION FOR PIECEPARTS The use of SnPb (Tin Lead) plating other t
49、han as part of an electrical joint is forbidden by most RoHS legislation. Where leaving material bare is unacceptable, pure tin may be used. Careful consideration should be given to the use of pure tin, limiting it to areas where tin whisker growth is unlikely to lead to an electrical short. Tin should never be specified for use below -40 degrees C, because the tin can lose adhesion and flake off at low temperatures Plating shall be specified as: Two or more microns nickel, followed with 4 or more micro
