AMS C 26074 PDF

It is recommended, therefore, that this specifications not be specified for new designs. The Aerospace Materials Division, however, does not recommend these specifications for future use in new designs. Similar but not necessarily identical processes are covered in the following specifications. AMS-CB is therefore reinstated and is designated as a noncurrent document.

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It is recommended, therefore, that this specifications not be specified for new designs. The Aerospace Materials Division, however, does not recommend these specifications for future use in new designs. Similar but not necessarily identical processes are covered in the following specifications. AMS-CB is therefore reinstated and is designated as a noncurrent document.

The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user. SAE invites your written comments and suggestions. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. Military Specification MIL-CE, and contains only minor editorial and format changes required to bring it into conformance with the publishing requirements of SAE technical standards.

Any part numbers established by the original specification remain unchanged. TSB rules provide for a the publication of portions of unrevised government specifications and standards without consensus voting at the SAE Committee level, and b the use of the existing government specification or standard format.

Under Department of Defense policies and procedures, any qualifications requirements and associated qualified products lists are mandatory to DOD contracts.

SCOPE: 1. Class 1 Class 2 Class 3 Class 4 1. Aluminum alloys non-heat treatable, and beryllium alloys processed to improve adhesion of the nickel deposit.

Aluminum alloys, heat-treatable, processed to improve adhesion of the nickel deposit. Composites can be plated directly by using special pretreatments to prevent the basis material from contaminating the bath or to obtain adequate coating adhesion. Tensile strength: All steel parts having an ultimate tensile strength of , psi, or above, shall not be coated without approval of the procuring activity. Hardness measurement:. Stress relief heat treatment: Prior to cleaning and coating, all steel parts having a hardness of Rockwell C40 or above, which have been machined, ground or surface hardened includes cold worked but not shot peened surfaces , shall be given a stress-relief heat treatment at a temperature that will produce maximum stress relief without reducing the hardness to less than the specified minimum.

Unless otherwise specified, the shot peening shall be accomplished on all surfaces for which the coating is required and all immediately adjacent surfaces when they contain notches, fillets or other abrupt changes of section size where stresses will be concentrated. Coating properties: General requirements: Manufacturers are given latitude in the selection of specific plating bath formulations used for the chemical deposition of an amorphous nickel-phosphorous metallic compound provided the coating obtained meets the requirements of this specification.

Equipment, solutions, and process procedures shall be subject to the approval of the procuring activity. Thickness: Unless otherwise specified, minimum thickness of the nickel coating shall be 0. It also shall be impossible to detach any area of the coating with a sharp instrument on the outside radius of the bent-test specimen.

Formation of cracks that do not result in loss of plating adhesion is acceptable. Corrosion resistance: Grade A coatings on aluminum alloys and grade C coatings on iron alloys after plating and all required thermal treatments shall show no visual evidence of corrosion of the basis metal when tested in accordance with 4. When tested in accordance with 4. Heat treatments: Class 2 hardness coatings: Class 2 coatings shall have a minimum hardness of knoop or equivalent vickers when tested in accordance with 4.

Class 2 coatings on steel parts that have a hardness of Rockwell C40 or above are required to be tested in accordance with 4. The hardness can be achieved by heating the part see 4. Class 3 coatings: Coated nonheat-treatable aluminum parts shall be heated for 1 to 1. Basis material b.

Number of this specification. Class and grade of coating. Nickel coating: The nickel coating shall be smooth, adherent, and free from visible blisters, pits, nodules, porosity, cracks and other defects. All details of workmanship shall conform to the best practices for high quality coating. Except as otherwise specified in the contract or purchase order, the contractor may use his own or any other facilities suitable for the performance of the inspection requirements specified herein, unless disapproved by the Government.

The Government reserves the right to perform any of the inspections set forth in this specification where such inspections are deemed necessary to ensure supplies and services conform to prescribed requirements. The absence of any inspection requirements in the specification shall not relieve the contractor of the responsibility for ensuring that all products or supplies submitted to the Government for acceptance comply with all requirements of the contract.

Sampling inspection, as part of manufacturing operations, is an acceptable practice to ascertain conformance to requirements, however, this does not authorize submission of known defective material, either indicated or actual, nor does it commit the government to accept defective material. Classification of inspection: The inspection requirements specified herein are classified as quality conformance inspection see 4. The separate specimens shall be of a basis material equivalent see 6.

For example, a cold-rolled steel surface shall not be used to represent a hot-rolled steel surface; owing to the impracticability of forging or casting separate test specimens, hot-rolled steel specimens may be used to represent forged and cast steel parts. The separate specimens shall be strips approximately 1-inch wide, 4-inches long, and 0. These specimens shall be introduced into a lot at regular intervals prior to the cleaning operations preliminary to coating and shall not be separated therefrom until after completion of the processing.

Periodic microscopic destructive thickness and adhesion tests shall be performed as a referee method to verify comparable nondestructive tests for the purpose of process control assurance. Visual inspection: Each of the sample parts selected in accordance with 4.

Thickness nondestructive tests : Each of the sample parts selected in accordance with 4. The part shall be considered nonconforming if one or more measurements fail to meet the specified minimum thickness. Sampling plan B - Sampling procedures for evaluating hydrogen embrittlement relief destructive test - Class 1 and 2: A hydrogen embrittlement relief test shall be run once per month on a random sample of 4 parts as specified in 4.

Sampling plan C - Sampling procedure for adhesion tests: A random sample of 4 parts shall be selected from each inspection lot which has more than 15 parts see 4.

If the number of parts in an inspection lot is 15 or less, the number of parts in the sample shall be 2 or 3 as determined by the procuring activity. Adhesion: Each part, or specimen shall be tested as specified in 4. Failure of one or more of the test specimens shall constitute failure of the lot.

The amount of testing may be reduced provided the results in the consecutive months indicate a uniform product meeting the test requirements is being produced, and providing the manufacturer agrees to maintain the same manufacturing procedures or develops alternative acceptable manufacturing procedures.

Sampling Plan E: Sampling procedure for destructive tests of coating thickness. At least once per calendar quarter, a coated part, or a separately coated specimen prepared in accordance with 4. Periodic verification of the instrumental methods must be made in accordance with 4.

Embrittlement relief: Compliance with 3. Parts--spring pins, lock rings, and so forth--that are installed in holes or rods shall be similarly assembled using the applicable parts specifications or drawing tolerances which impose the maximum sustained tensile load on the plated part. The selected samples shall be subjected to a sustained tensile load equal to percent of the maximum design yield load for which the part was designed. Parts that require special fixtures, extreme loads to comply with the above requirements, or where the maximum design yield load is not known, may be represented by separate test specimens.

The articles, parts or test specimens shall be held under load for at least hours and then examined for fracture. The lot shall be rejected if any coated article, part, or test specimen shows cracking or fracture of the basis metal. The separate test specimens used for salt-spray testing shall be 4 inches by 6 inches. NOTES: This section contains information of a general or explanatory nature that may be helpful, but is not mandatory. Excellent uniform deposits are produced on irregular parts.

Coated parts--that is, those parts used in air compressors, missile-fuel injector plates, pumps, reciprocating surfaces, and so forth are protected from oxidation, corrosion and wear. With aluminum electronic devices, not only is product contamination prevented, but the coated parts facilitate soldering when used in conjunction with a mildly activated RMA or activated RA rosin flux.

Coated parts of stainless steel similarly facilitate brazing. Title, number and date of the specification. Class and grade, and heat treatment or condition see 1. Issue of DODISS to be cited in the solicitation, and if required, the specific issue of individual documents reference see 2. When measuring heat-treated coatings containing more than 8 percent phosphorous, the instrument should be calibrated against heattreated standards of known coatings thickness or equivalent calibration foils.

Heat treatment increases coating magnetism. Measurement of electroless nickel coatings containing less than 8 percent phosphorous by a magnetic method is not recommended.


Electroless Nickel Plating

Electroless nickel plating is an process that codeposits a nickel-phosphorous alloy without need for an externally applied electrical current. The electroless nickel plating process occurs from a chemical reduction of the nickel ions within the electroless nickel solution onto a metallic substrate rather than deposition of the ions from an applied current. As a result, the electroless nickel deposit is free of many of the problems associated with traditional electrolytic nickel including edge buildup and non-uniform coating. Electroless nickel deposits are extremely uniform, corrosion and erosion resistant and provide excellent lubricity. APT offers loose-piece barrel, rack and vibratory electroless nickel plating on nearly any metallic substrate including nearly any ferrous, cupreous and aluminum alloys as well as many exotic alloys. The electroless nickel phosphorous content affects the properties of the deposit significantly including hardness, corrosion resistance and magnetism.


MIL-C-26074 E Electroless Nickel Plating

There are four 4 different classes and three 3 different grades of electroless nickel plating used throughout the industry to meet different specifications. The class of an electroless nickel plating refers to the post-plating heat treatment process that is used; the grade of an electroless nickel plating refers to its thickness. Heat treatment after electroless nickel plating provides evidence of proper adhesion and improves the crystalline structure of the amorphous deposit for greater hardness. Six heat-treat classes are available. Class 1 is for electroless nickel coatings that require no heat treatment. Classes 2 through 5 exist at various levels between these two extremes. Electroless nickel coatings are graded A, B, or C.


SAE AMS-C-26074




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