The electrolizing thin, dense, chromium process 285 the signi. During the last decade the engineering applications for nickel and chromium coatings have gained in importance. The true hardness of chromium is achieved from deposits of 0. The basic difficulty of electrodepositing metallic chromium is evident. The metallization adds a high optical and material value to work pieces.
Therefore characteristic features of chrome plating are decisive. Nickel and chromium plating, second edition, does not merely update the first edition but also places additional emphasis on certain methods that have achieved increased industrial use in the 14 years since the first edition was published. The handbook of hard chromium plating open library. Chrome plating process was occurred by electrochemical and chromium layer deposited. After discussion with industry representatives, the category of. Hard chromium plating is also known as industrial, functional, or engineering chromium plating. Chrome engineering representative is recommended in order to take fullest advantage 0t the properties of chromium as well as to avoid potential problems. The thinner deposits being used to substantially increase the life of. Hard chrome machine plating process procedures plating. For some special applications where hydrogen embrittlement is a concern, a post plate bake may be required. Plating of very large parts by selective surface masking hydrogen embrittlement parts with a hardness of 36 rc or greater will be baked a. Hard chrome plating, also called engineering chrome, is an electrolytically applied metal coating. Our concern for the rest of this paper, however, will be with hard chrome plating.
Chrome plating less commonly chromium plating, often referred to simply as chrome, is a technique of electroplating a thin layer of chromium onto a metal object. Scott, in handbook of industrial membranes second edition, 1995. Hard chrome plating leaves a layer of chrome from 0. Sometimes, a less expensive imitator of chrome may be used for aesthetic purposes.
Ventilation considerations for chromium plating tanks. Currently, functional chromium plating from a criii bath is not commercially available because of the difficulty to plate thick chromium coatings with the appropriate properties. Hard chrome plating uses chromic acid solution which is responsible for the release of chromium hexavalent ions that are hazardous even in minor quantities. Nickel and chromium plating 2nd edition 9780408011242.
Pdf the significance and determination by image analysis. Many of the best metal finishing books are out of print and hard to find. As an instructor in various finishing courses, i have frequently made the statement over the years that in the field of metal finishing there is very little black and white, just a great deal of grey. Buy the handbook of hard chromium plating by robert k. This part is regarded as the cathode and as dc current travels through lead anodes, chromium forms on the surface of the component. Nasfs chromium plating course is beneficial for operators and supervisors of job shops and captive shops performing hard chromium plating operations on a variety of substrates. These defects may be in the original metal surface or may be caused by preplate finishing. Emission factor documentation for ap42 electroplating final. Poor chrome appearance in nearly all cases, a bright chromium deposit is the most desirable hard chrome plating result.
Chrome plating to finish size or overplating and grinding prior to finalizing a specification, consultation with a u. The literature is somewhat sparse on the subject of ventilation of a chromium plating tank, and i will not claim to be an expert on the subject. High resistance to wear hardening up to 1,100 hv, making chromium significantly harder than casehardened or nitrided steels good corrosion resistance through. The main component of all hard chromium plating solutions is chromium trioxide cro3 referred also as chromic acid. Books about hard chromium and nickelchrome plating plants. The book begins by tracing the history of nickel and chromium plating. Chromium plating continues to be the coating of choice for many metal finishing applications. Hard chrome is used as a wear resistant coating not only on steel but also on a wide variety of other metals. For info on all this, you can try chromium plating by r. The dura catalysts used in decorative chrome plating promote deposition at higher speeds, greatly increase the throwing power of the deposit and activate the. For quick reference, the information presented here is also summarized in appendix 7. Hard chrome plating is a type of electrolytic process that makes use of an electrolyte that is based in chromic acid. Weiner, or guffies excellent book, the handbook of hard chromium plating. Save up to 80% by choosing the etextbook option for isbn.
Baths for hard chromium coatings, unlike the bath for protective decorative chromium plating, must be designed for work at high current densities. The properties of electrodeposited metals and alloys. Consider a very simple plating cyclesoak clean, electroclean, rinse, acid dip, rinse, nickel plate, rinse and dry. Trivalent chromium replacements for hexavalent chromium plating. Guffie, 1986, gardner publications edition, in english. I have, however, collected some information over the years, so lets tackle the subject of what goes into a. In addition, the low current efficiency and low plating rate of criii baths lead to unfavorable economics. The cost of chemicals for the nickel plating is higher than that for copper, chromium or zinc plating. A functional trivalent chromium process to replace.
Hard chrome, flash chrome, industrial chrome applicable specifications. The handbook of hard chromium plating 1986 edition open. Terms in this handbook terms used in this publication relate to industry practice and are commonly understood by plating professionals. Hard chromium or industrial chromium plating refers to relatively thick chromium deposits applied to a base material because of the hardness, wear resistance, andor corrosion resistance of the. Im searching books and publication about hard chromium plating, i read about a book called the handbook of hard chromium plating by guffie, but is not available on amazon or any other book sellers. Hard chrome plating is commonly applied to various types of steel and is almost always thicker than decorative chrome plating. It can be noted that chromium is not included in the group of metals easily electrodeposited at high current efficiencies from aqueous solutions. The handbook of hard chromium plating, gardner publications, inc. The hard chromium plating coatings with 60 microns thick have been reported, and the various factors associated with the trivalent chromium performance and related process have been investigated 8. The handbook of hard chromium plating 1986 edition. In hard plating, a relatively thick layer of chromium is deposited directly on the base metal.
Hard chromium has excellent lubricity and antigalling properties. In decorative applications, the chrome is plated as a thin 0. Isbn 9781569900338 the handbook of hard chromium plating. For example, the trivalent chromium plating hard chromium coatings were applied on vehicle parts, printing roller, and worm9 10.
It describes processing steps and conditions for hard chromium plating. Controlling hexavalent chromium exposures during electroplating. Introduction the document compilation of air pollutant emission factors ap42 has been published by the u. The significance and determination by image analysis of microcrack density in hard chromium plating article pdf available in plating and surface finishing volume 3issue 2. For instance, plating of machine parts for the shipbuilding, plastic, paint and printing industries, plating of cutting and forming tools and inside hard chromium plating of firearm barrels are suitable applications.
Mar 11, 2012 the handbook of hard chromium plating by robert k. Dec 04, 2010 open library is an initiative of the internet archive, a 501c3 nonprofit, building a digital library of internet sites and other cultural artifacts in digital form. The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness. The term decorative plating is used to describe practices, processes and outcomes for a broad range of applications, but the term decorative often masks the critical nature of the outcome required. Table 1 shows a calculation of the number of possibilities that. The course can also benefit sales personnel who work for suppliers of hard chromium, and equipment. Inside chromium plating of tubes and other hollow sections is especially easy to perform. This article presents the major uses of hard chromium plating, and focuses on the selection factors, plating solutions, solution and process control, equipment, surface preparation, and crack patterns and other characteristics of hard chromium plating. Hard chromium plating is produced by electrodeposition from a solution containing chromic acid and a.
But if you learn the fundamentals, and learn how to apply them to your work, you will be well on your way to being a skilled hard chrome plater and producing quality parts. Practical problems in bright and hard chromium electroplatingpart i by n. Chromium is the hardest of the most commonly deposited metals. The model indicates uneven plating thickness across the height of the cathode the model must be modified to better incorporate effects of anode height process parameters, such as solution conductivity and anodecathode spacing, have significant effect on chrome plating excerpt from the proceedings of the 20 comsol conference in boston. Industrial hard chrome plating chem processing, inc. This deposited on the steel bars, must ensure increased corrosion resistance, low friction coefficient, high hardness and high wear resistance. Electrolytes for deposition of hard chromium coatings were similar to those for bright chromium plating, except that concentrated solutions are not used. This article discusses the corrosion of chromium electrodeposits and the ways for optimizing corrosion resistance. The hardness and corrosion properties of trivalent chromium.
Corrosion of electroplated hard chromium corrosion. Hard chrome plating is applicable to materials like. Practical problems in bright and hard chromium electroplating. Hard chrome machine plating process procedures is a technology that coat a thick plating layer in a variety of matrix surfaces, its thickness generally more than 20. The most familiar usage is on metal and plastic automotive trim. Hard chromium electroplating in hard plating, a relatively thick layer of chromium is deposited directly on the base metal usually steel to provide a surface with wear resistance, a low coefficient of friction, hardness, and corrosion resistance, or to build up surfaces that have been eroded by use. High resistance to wear hardening up to 1,100 hv, making chromium significantly harder than casehardened or.
Hard chrome plating is an electrolytic method of depositing chrome for engineering applications, from a chromic acid solution. T oday almost all of the hard chromium func tional and a majority of the bright decora tive chromium electroplating is done in baths, which are either identical to the original patent1 or vary from it only slightly in the use of different secondary. The process hard chrome plating is an electrolytic method of depositing chrome for engineering applications, from a chromic acid solution. Hard chrome plating demonstrates excellent hardness and lubricity, minimizes wear, reduces friction and prevents galling. In contrast, thin dense chrome plating has a thickness from 0. Hard chrome plating it is hard to imagine modern technology without hard chrome plating. The thinner deposits being used to substantially increase the. For more than forty years, academic and industrial researchers from all around the world have taken a strong interest in alternative processes for hard chromium plating using hexavalent ions. Unlike many others nickel plating requires much more metal because, nickel is plated to several tens microns in thickness as primer for chromium plating. Pdf an overview of hard chromium plating using trivalent. Individual plant reports which include more detailed information on specific plant processes and controls are available from the national technical information service.
Hard chromium differs from decorative chromium not only because of. Various types of hard chrome include microcracked chromium, microporous chromium, porous chromium and crack free chromium. Hard chrome plating is one of the trickiest metal finishing processes to master. Some are expensive but poorly described by the book sellers. Industrial hard chromium plating surface engineering. The handbook of hard chromium plating guffie, robert k. Second edition handbook for solving plating problems.
When a part is pulled from the hard chrome plating tank, chromium may not have deposited over the entire plated area. The steps include pretreatment, electroplating, and posttreatment. Chromium plating has been carried out on a commercial basis since 1924. Hard chrome plating double on a steel c45e the thickness of chromium is between 56 58m, as shown in figure 8. Chromium has withstood the competitive challenges due to its unmatched aesthetics as well as its. Chromium is widely used in the metal finishing industry for both decorative and hard chrome plating. Catalytic effect of sulphuric acid in the process of. Hard chromium plating is produced by electrodeposition from a solution containing chromic acid and a catalytic anion in proper proportion. In this third edition the chapter dealing with engineering applications has been updated and expanded to include more information on electroforming and composite coatings, and engineering applications have been emphasised in the additions to the chapter on autocatalytic deposition of. Sixtyfour plating and cleaning tanks were evaluated with the major emphasis on hard chromium plating.
No other metal can offer better overall properties then chromium. Surface cleaning classification and selection of cleaning processes alkaline cleaning solvent cold cleaning and vapor degreasing emulsion cleaning molten salt bath cleaning ultrasonic cleaning acid cleaning mechanical cleaning systems pickling and descaling 2. Amazing fastest wood lathe machine operation, modern cnc automatic wood turning milling carving duration. Open library is an initiative of the internet archive, a 501c3 nonprofit, building a digital library of internet sites and other cultural artifacts in digital form. The char acteristic bluish haze of plated chromium offers an attractive, popular surface finish. Demand for chromes bright and lustrous finish continues to grow despite competition from other finishes, such as organic coatings and vapor deposition. Find 9781569900338 the handbook of hard chromium plating by guffie at over 30 bookstores. The appropriateness of the use of trivalent chromium plating technologies. Hard chromium when chromium is applied for any other purpose, or when appearance is a lesser feature, the process is commonly referred to as hard chromium plating, or functional chromium plating. Pdf nickel and chromium plating download full pdf book. In this third edition the chapter dealing with engineering applications has been updated and expanded to include more information on electroforming and composite coatings, and engineering applications have been emphasised in the additions to the chapter on autocatalytic.
The handbook of hard chromium plating 9781569900338 by guffie, robert k. Hard chrome plating is an electroplating process in which chromium is deposited from a chromic acid solution. How electroplating operations cause crvi exposure in the workplace there are several factors that contribute to hexavalent chromium exposure in the workplace, including. Decorative chrome electroplating hard chrome electroplating chromate conversion coatings. Gardner publications, 1986 chromium plating 192 pages.