Control Technology Assessment: Metal Plating and Cleaning Operations
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Methods to Improve the Corrosion Performance of Microporous Nickel Deposits
Methods to Improve The Corrosion Performance Of Microporous Nickel Deposits By Robert A. Tremmel During the last several years, nickel, which is essentially sulfur- microporous nickel-chromium free, plus a thinner layer of bright coatings have been critically nickel. Duplex nickel provides scrutinized by the automotive corrosion protection that is far industry. Today these coatings must superior to single layer systems. In be free of all surface defects, even these duplex systems, when corrosion after long-term exposure to acceler- occurs through a pore in the chro- ated tests and in real-life service. mium plate, the bright nickel is While proper control of all the rapidly penetrated until the semi- multi-layer nickel deposits is bright nickel is reached. Because the important, blemish-free surfaces electrochemical potential of the semi- Fig. 1—Corrosion mechanism of decorative nickel- can only be obtained when the chromium deposits. bright deposit is greater than that of microdiscontinuity and the activity the bright nickel deposit, thereby of the post-nickel strike are prop- making it more noble, the bright erly achieved and maintained. This also be free of surface defects1. nickel layer will corrode preferen- edited version of a paper presented Simply meeting porosity specifica- tially to the semi-bright nickel layer. at SUR/FIN® ’96—Cleveland shows tions is not enough. The size of the As the pit widens, however, some that research indicates that the pores is important, as well as the attack will eventually occur in the most important factor is the electrochemical potential of the semi-bright nickel layer and ulti- electrochemical potential of the microporous nickel strike. -
Analysis of Hard Chromium Coating Defects and Its Prevention Methods
International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-2, Issue-5, June 2013 Analysis of Hard Chromium Coating Defects and its Prevention Methods L.Maria Irudaya Raj, Sathishkumar.J, B.Kumaragurubaran, P.Gopal Abstract — This paper mainly deals with various Chromium coating defects that occur while electro plating of different II. COATING mechanical components and methodology adopted to prevent it. It also covers suggestions to minimize this problem. This paper Coating may be defined as a coverage that is applied over contains new suggestions to minimize the problems by using the surface of any metal substrate part/object. The purpose of recent technological developments. Since the chemicals used for applying coatings is to improve surface properties of a bulk chromium coating are posing threat to environment it is need of material usually referred to as a substrate. One can improve the hour to minimise the use such chemical consumption. The amongst others appearance, adhesion, wetability, corrosion reduction in defective components will increase productivity as resistance, wear resistance, scratch resistance, etc. well as protect the environment to some extent It also describes the various alternate coating methods for chromium coating through III. HARD CHROME COATING PROCESS which we can achieve the required surface properties. India being a Developing country .for various coating application chromium The coating process consists of Chrome Chemical Bath, is used. Since the process is slow and involves lengthy cycle time Anode, Cathode potentials, part to be coated, Heaters, unless the defects are minimized the products cannot be delivered rectifiers & Electrical control systems. Initially the bath has to in time which will create loss to the Industries. -
Plating on Aluminum
JJW o NBSiR 80-2142 (Aluminum Association) on Aluminum AUG 5 1981 D. S. Lashmore Corrosion and Electrodeposition Group Chemical Stability and Corrosion Division National Measurement Laboratory U.S. Department of Commence National Bureau of Standards Washington, DC 20234 November 1980 Final Report Prepared for The Aiuminum Association The American Electropiaters Society 818 Connecticut Avenue, N.W. 1201 Louisiana Ave. Washington, DC 20006 Winter Park, FL 32789 NBSIR 80-2142 (Aluminum Association) PLATING ON ALUMINUM D. S. Lashmore Corrosion and Electrodeposition Group Chemical Stability and Corrosion Division National Measurement Laboratory U.S. Department of Commerce National Bureau of Standards Washington, DC 20234 November 1980 Final Report Prepared for The Aluminum Association The American Electroplaters Society 818 Connecticut Avenue, N.W. 1201 Louisiana Ave. Washington, DC 20006 Winter Park, FL 32789 U.S. DEPARTMENT OF COMMERCE, Philip M. Klutznick, Secretary Jordan J. Baruch, Assistant Secretary for Productivity, Technoiogy, and Innovation NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director Table of Contents Page 1. Introduction 1 2. Program Summary 2 3. Phosphoric Acid Anodizing Prior to Plating 10 3.1. Adhesion Data 10 3.2. Microstructure of the Anodic Film 17 3.2.1. Microstructure of nickel plated onto the anodic 19 film 3.2.2. Initial Stages of Oxidation 25 3.3. Electrochemical Measurements 32 3.3.1. Current Density versus Applied Potential 32 3.3.2. Scanning Voltammetry 33 4. Immersion Deposition 37 4.1. Scanning Voltammetry 37 4.2. Dissolution Data 41 4.3. Discussion 44 5. Adhesion Theory 45 5.1. Adhesion of Metallic Coatings 45 5.2. Pre-existing Crack--Griffith Criterion 52 5.3. -
Electrodeposition of Nanocrystalline Cobalt Alloy Coatings As a Hard Chrome Alternative
NAVAIR Public Release 09-776 Distribution: Statement A - "Approved for public release; distribution is unlimited." ELECTRODEPOSITION OF NANOCRYSTALLINE COBALT ALLOY COATINGS AS A HARD CHROME ALTERNATIVE Ruben A. Prado, CEF Naval Air Systems Command (FRCSE) Materials Engineering Laboratory, Code 4.3.4.6 Jacksonville, FL 32212-0016 Diana Facchini, Neil Mahalanobis, Francisco Gonzalez and Gino Palumbo Integran Technologies, Inc. 1 Meridian Rd. Toronto, Ontario, Canada M9W 4Z6 ABSTRACT Replacement of hard chromium (Cr) plating in aircraft manufacturing activities and maintenance depots is a high priority for the U.S. Department of Defense. Hard Cr plating is a critical process that is used extensively within military aircraft maintenance depots for applying wear and/or corrosion resistant coatings to various aircraft components and for general re-build of worn or corroded parts during repair and overhaul. However, chromium plating baths contain hexavalent chromium, a known carcinogen. Wastes generated from these plating operations must abide by strict EPA emissions standards and OSHA permissible exposure limits (PEL), which have recently been reduced from 52µg/m3 to 5µg/m3. The rule also includes provisions for employee protection such as: preferred methods for controlling exposure, respiratory protection, protective work clothing and equipment, hygiene areas and practices, medical surveillance, hazard communication, and record-keeping. Due to the expected increase in operational costs associated with compliance to the revised rules and the -
Surface Engineering of Specialty Steels
ASM Handbook, Volume 5: Surface Engineering Copyright © 1994 ASM International® C.M. Cotell, J.A. Sprague, and F.A. Smidt, Jr., editors, p 762-775 All rights reserved. DOI: 10.1361/asmhba0001306 www.asminternational.org Surface Engineering of Specialty Steels J.R. Davis, Davis & Associates SPECIALTY STEELS encompass a broad P/M materials for structural parts are iron-copper- amount of admixed graphite and the composition range of ferrous alloys noted for their special carbon, iron-nickel-carbon, and iron-carbon. of the sintering atmosphere. processing characteristics (powder metallurgy al- Parts made from these materials respond to heat loys), corrosion resistance (stainless steels), wear treatment with a defined hardenability band. Iron Deburring P/M Parts (Ref 4) resistance and toughness (tool steels), high parts that are low in carbon and high in density strength (maraging steels), or magnetic properties can also be case hardened. Although cleaning and deburring generally are (electrical steels). Each of these material considered different operations, they are often groupsmwith the exception of stainless steels, Designation of Ferrous P/M Materials accomplished simultaneously. Therefore, much which were discussed in the previous article in of the discussion on deburring is applicable to the this Sectionmwill be reviewed below. Additional Ferrous P/M materials are customarily desig- subsequent section of this article on cleaning. information on these materials can be found in nated by the specifications or standards to which The inherent porosity in P/M parts demands Volumes 1 and 2 of the ASM Handbook. they are made, such as those listed in Table 1. special considerations in all secondary opera- Comparable standards are published by ASTM, tions. -
AMS-QQ-P-416.Pdf
00-P-41 6F i“October 1991 SUPERSEDING ~-P-416E 18 Aprtl 1986 FEDERAL SPECIFICATION PLATING, CADMIUM (ELECTRODEPOSITED) This specification has been approved by the Commissioner, Federal Supply Service, General Services Adminlstratlon, for use by all Federal Agencies. 1. SCOPE AND CLASSIFICATION 1.1 Scope. This specification covers the requirements for electro- deposited cadmium platlng. 1.2 Classification. Cadmium plating shall be of the following types and classes, as specified (see 6.2): 1.2.1 Types. I - As plated II - With supplementary chromate treatment (see 3.2.9.1) 111 - With supplementary phosphate treatment (see 3.2.9.2) 1.2.2 Classes. 1- 0.00050 inch minimum 2- 0.00030 inch minimum 3- 0.00020 Inch mlnlmum 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications and standards. The following specifications and standards form a part of this document to the extent specified here~n. Unless otherwise specified, the issues of these documents are those listed in the issue of the Department of Defense Index of Specifications and Standards (0001SS) and supplement thereto, cited in the solicitation (see 6.2). Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use In improving this document should be addressed to: Naval Air Engineering Center, Systems Engineering and Standardization Department (Code 5312), Lakehurst, NJ 08733-5100, by using the attached Standardization Document Improvement Proposal (DD Form 1426), or by letter. AhiSC N/A AREA MFFP OISTRIEHJTION STATEMENT A. Approved -
Download the Table of Contents
contents Chapter 1 introduction 1 1.1 introduction 1 Chapter 2 Wear and friction properties of surfaces 7 2.1 introduction 7 2.2 abrasive Wear 9 2.2.1 low -stress scrAtching AbrAsion 10 2.2.2 high-stress grinding AbrAsion 11 2.2.3 gouging AbrAsion 12 2.3 adhesive Wear 12 2.4 case study: solid lubricants and triboloGical characterisation hereof 16 2.4.1 block-on-ring test for solid lubricAnts 17 2.4.2 fAlex pin And vee block test for solid lubricAnts 19 2.5 fatiGue Wear 21 2.6 corrosive Wear 22 2.6.1 cAse study: fretting 23 2.7 erosive Wear 27 2.8 references 33 2.9 recommended additional readinG 33 2.10 relevant standards 33 Chapter 3 introduction to corrosion 37 3.1 introduction 37 3.2 the pourbaix diaGram 48 3.3 strateGies for corrosion protection 52 3.3.1 conversion coAtings As corrosion protection 52 3.3.2 AdditionAl corrosion protection strAtegies 55 3.4 typical appearance of surface corrosion 56 3.4.1 uniform corrosion 57 3.4.2 gAlvAnic corrosion 61 3.4.3 crevice or deposit corrosion 63 3.4.4 fretting corrosion 68 3.5 recommended additional readinG 69 IX ◆ Part1.indb 9 21/04/13 21.28 Advanced Surface Technology Chapter 4 basic electrochemistry for surface modifications 71 Chapter 6 Guidelines for electro-chemical deposition 149 4.1 introduction 71 6.1 introduction 149 4.2 basic electrolytic processes 72 6.2 material distribution and Geometry 149 4.2.1 hydrAtion of the metAl ion 72 6.2.1 types of overpotentiAl (polArizAtion types) 149 4.2.2 dissociAtion of the solution 73 6.2.2 optimizing mAteriAl distribution 151 4.2.3 interAction -
UK HITEA Project for Chromate Replacement.Pdf
REACH Compliant Hexavalent Chrome Replacement for Corrosion Protection (HITEA) Brad Wiley Rolls-Royce plc Image courtesy of Manchester University Trusted to deliver excellence The information in this document is the property of the members of the Project Consortium (Technology Strategy Board Project 101281) and may not be copied or communicated to a third party, or used for any purpose other than that for which it is supplied without the express written consent of the consortium members. Approved for distribution – Rolls Royce, 12/8/14 The Need 2 • On the 1st June 2007 the European Union enacted REACH – Registration, Evaluation, Authorisation and Restriction of Chemicals – legislation. • Hexavalent chrome compounds are classified as substances of very high concern (SVHC) because they are Carcinogenic, Mutagenic or Toxic for Reproduction (CMR). • The stringent regulation of these compounds means that suitable alternatives must be investigated and implemented to ensure that product performance and business continuity is maintained. • The sunset date for hexavalent chrome compounds is September 2017. Engine Guide Vane Actuator 3 Aluminium Housing •Forged / Make from Solid •Chromic acid anodised (CAA) externally. Aluminium Piston •Chromic Acid Anodised Head •Hard Chrome Plated Stem •Chromate Conversion Coating (CCC) Images courtesy of Rolls-Royce Controls & Data Services Ltd. The Role of the AAD and Materials KTNs 4 • A joint AAD and Materials KTN workshop in 2011 resulted in: - Definition of the hexavalent chromium replacement problem - Outline of a possible research strategy - Potential partnerships to address the problem • The KTNs influenced the TSB collaborative R&D competitions to ensure REACH was a priority theme. • Created the opportunity for the UK to position itself as the leading exponent of REACH-compliant materials science. -
Fundamentals of Heat Treating and Plating
SEMINARS FOR ENGINEERS Fundamentals of Heat Treating and Plating Fasteners and Other Small Components About the Seminar: Benefits of Attending This two-day seminar was developed for engineers and technical Gain an understanding of what is occurring when a fastener is heat treated personnel to gain a high level, broad understanding of why and Become familiar with the common heat treating processes how fasteners and other similar items are heat treated and plated for fasteners or coated. The demands on today’s fasteners are ever increasing Understand when to specify specific processes or equipment and these two process steps play a critical role in how well the Recognize potential failures modes fastener will perform its intended function. Gain an understanding of the benefits of different platings and coating This seminar will begin by exploring the fundamental metallurgical Understand when to specify certain plating or coating pro- transformations and principals that yield the mechanical changes cesses desired by the fastener designer or engineer. Each process will Gain insight into plating and coating performance and rela- be examined in greater detail to understand how the process tive cost to achieve these goals achieves these underlying principals and what practical effects it Explore current issues in regulation and environmental protection has on the fastener. Control points will be investigated to gain an understanding of, not only how the process remains in control, but also how it can go wrong and the consequences when it does. Concepts Covered Day two will explore platings and coatings. There are a multitude Metallurgical transitions of good options today and this seminar shall look at those favored Hardenability by large fastener consuming industries. -
REACH Regulation: Replacement of Hard Chrome With
REACH REGULATION: For many years hard chrome plating was an industrial standard process for wear and corrosion protection, but REPLACEMENT OF HARD due to the European REACH regulations the application CHROME WITH S³P of hard chrome plating will be highly regulated after 2017. Beside desired properties like wear resistance, medium corrosion resistance and galling resistance the application of hard chrome is limited by reduced fatigue strength and flaking of the coating. S³P surface-hardening of corrosion resistant materials is an efficient alternative to hard chrome, which is superior to a coating in many applications thanks to its technological properties. S³P – Specialty Stainless Steel Processes Replacement of Hard Chrome Corrosion resistant, hard yet ductile Bodycote S³P (Specialty Stainless Steel Processes) offers processes that produce a very hard yet ductile diffusion zone with a surface hardness of more than 1000 HV 'microhardness' on the surface of corrosion resistant steels, nickel-based and cobalt-chromium alloys. Benefits of the processes include considerably enhanced wear resistance, which is superior to hard chrome plating in many areas, fig. 1. Unlike coatings, the bending fatigue strength can also be significantly improved, which allows a more efficient design of Fig. 1 Wear width in pin-and-disc tribometer (Al2O3 ball Grade 25 components. No flaking occurs on the hard outer surface either. according to DIN 5402:2012), contact pressure: 100 N, sliding speed: 66 mm / s, wear tolerance: 5 m, base material: 1.4404; Especially product-contact applications of hard chromium can the S³P-treated component exhibits the strongest abrasion be safety-critical, fig. -
An Evolution of Trivalent Chromate Technologies
Alternatives to the Hexavalent Chromates: An Evolution of Trivalent Chromate Technologies. By William Eckles and Rob Frischauf, Taskem, Inc. Fourth generation trivalent chromate hexavalent chrome in the work place, conversion coatings exhibit excellent except for hard chrome plating.1,2 The corrosion resistance and self-healing best alternative to hex-chrome is properties, not unlike hexavalent trivalent chromium for both chromate chromate conversion coatings. These conversion coatings and for decorative self-healing trivalent chromate chrome plating. Consequently, trivalent conversion coatings incorporate chromate conversion coatings are chemically inert nanoparticles in the replacing conversion coatings containing conversion coating. The nanoparticles hex-chrome. This process of replacing add thickness and corrosion resistance hex-chrome with trivalent chrome has a to the chromate film. The migration of history going back to the 1970s. the nanoparticles into scratches in the conversion coating film produces the First generation trivalent chromates were self-healing effect. mixtures that were similar in composition to hexavalent chromates, What surface coating technologies are except that the oxidizing power was available to fight against corrosion, now supplied by either hydrogen peroxide or that hexavalent chromates are no longer by nitrates, in place of chromic acid or available? Surface coatings increase chromate salts. These early trivalent service life with increased corrosion chromates were used to produce a blue protection, aesthetic appeal, and coating on alkaline non-cyanide zinc. increased wear resistance. Zinc The coatings were thin (~60 nm), electroplate with chromate coatings are powdery, and provide limited corrosion the low-cost, bulk-applied coatings that resistance. What corrosion resistance are widely specified. Electroplated zinc they did provide was often limited to the is given post-plating treatments prevention of “finger staining,’ but not consisting of chromate conversion much more. -
Understanding Fasteners
MABUILDINterialsG MAselectionterials UNDERSTANDING faSTENERS Fasteners are an essential building material for the industry, but do you know the difference between the various types of steel and stainless steel products? Used in the wrong place, they are not going to stand the test of time. By Zhengwei Li, BRANZ Corrosion Scientist asteners, such as bolts, nails and a homogeneous structure, and the interface Coating screws, are used in timber-framed between the coating and the steel substrate is construction to hold structural compon- sharp. The adhesion is governed by the surface Steel ents together and attach claddings cleaning process before plating. Coating Micro-structure of electroplated zinc coating on steel. The F interface between the coating and the steel substrate is sharp. to the frame. Holding power (withdrawal thickness typically ranges from 7–15 µm. resistance) and corrosion perform ance are Mechanical plating probably the most important concerns when Mechanical plating is a batch process carried out choosing fasteners. in a rotating drum. The steel part is tumbled in Coating Improperly specified fasteners can loosen a mixture of zinc dust, chemicals (promoter or Steel when timber shrinks and swells with moisture accelerator), glass beads and water. The coating cycling. Deterioration of fasteners from corrosion is impacted onto the steel surface by the cold Micro-structure of mechanically plated zinc coating on steel. not only weakens the fastener, but the chemicals welding of fine-powdered zinc particles through the generated by corrosion can also attack timber tumbling action. As a result, the coating consists η - Zn phase surrounding the fastener. This significantly of flattened particles of zinc loosely bonded reduces the holding ability of the fastener-timber together.