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May 30-31, 1996
Sheraton Cleveland City Centre Hotel
Session Chairman: Allen Jones, CEF, Atotech USA, Inc., Somerset, NJ
1 p.m.-Corrosion of Hard Chromium Electrodeposits
Dr. Allen R. Jones, CEF, Atotech USA, Inc., Somerset, NJ
Hard chromium electrodeposits are used in a multitude of corrosive environments. Hard chromium is a barrier-type coating. The corrosion resistance of a given thickness of hard chromium can vary widely, depending upon the preplate and postplate finish of the part. The preplate, plating and postplating steps are all critical and interdependent with respect to corrosion resistance.The optimization of each of these steps and the system will be dis-cussed. Data on the corrosion resistance of hard chromium in various environments will be reviewed.
1:30 p.m.-Practical & Theoretical As-pects of Chromium Activation & Reverse Etching
N.V. Mandich, HBM Electrochemical Engineering Corporation, Lansing, IL
In chromium plating, reverse etching ("re-versing") is a critical step in the process, used either prior to the plating over the base metal or when replating (chromium over chromium). There is very little literature on this important step or on the electrochemical mechanisms involved. Practical aspects will be considered, to-gether with related chemistry and electrochemistry. The number of reversing methods will be presented, as well as the activation methods for bright chromium plating over nickel.
2:30 p.m.-AESF Research Project: Porous Ceramic Diaphragm-Separation of Metallic Impurities from Chromium Plating Baths
Professor Bob Selman, C.C. Li, S. Rao Guddati, T. Olsen, Illinois Institute of Technology, Chicago, IL
Experiments were carried out using a laboratory-scale ceramic diaphragm cell (also known as "porous pot") at different current densities with simulated spent hard chromium plating solutions having different concentrations of metallic impurities. The results show that the optimum conditions for the efficient operation of the cell depend on current density, initial pH, and the nature of the cathodic surface used. The rate of transport of impurities from the bulk plating solution into the pot was found to be controlled mainly by migration as a result of the electric field. The potential gradient across the diaphragm and the ratio of ceramic diaphragm area to the volume of spent solution determine the impurity removal rate from the plating solution. Low current densities favor the operation of the porous pot on a continuous basis, for on-line purification of plating solutions. A porous lead cathode gives a better on-line performance than a flat lead cathode, be-cause fewer interruptions for cleaning are required and the impurities precipitate as a compact sludge. When a flat lead electrode is used as cathode and the initial pot electrolyte is acidic, the impurities are likely to be coated onto the cathode as an adherent layer.
3 p.m.-New Chromium Plating Bath for Ultra-high-speed Plating
Dr. Kenneth R. Newby, Atotech USA, Inc. Somerset, NJ
Since its inception in the 1920s, chromium plating has been limited to operating temperatures at or below 140 °F (60 °C) and current densities usually below 5 ASI. These limitations were the result of a combination of tank lining materials and, more importantly, of catalyst stability at higher temperatures in relatively concentrated chromic acid solutions. The tank lining stability has been overcome by very long-lasting materials, such as PVDF. The catalyst stability problem was overcome with the introduction in the U.S. in 1994 of a new non-fluoride chemistry that is stable at temperatures exceed-ing 180 °F. This catalyst permits electro-platers to utilize current densities of 10 ASI and higher, depending only upon the current distribution capability of the part being plated. Deposit properties and appearance are that of deposits plated from "conventional" non-fluoride, high-speed chemistry. Early applications have included shock absorbers, struts, engine valve stems, aluminum engine cylinder walls, and piston rings.
3:30 p.m.-Sampling Techniques on Hard Chromium Tanks · The 306 Method
Kevin Walls, MARCOR Environmental, Inc., Hunt Valley , MD
Kevin Walls, an environmental consultant experienced in 306 air sampling, will provide a review of the 306 Isokinetic Stack Sampling Methodology and its application to the new Chromium MACT Standard. He will discuss the repeatability and accuracy of the test and the more general use of the technique for other compliance demonstrations.
· Comparison of Logical Applications for 306 and 306A
Whitby Ellsworth, National Chromium Company, Inc., Putnam, CT
Whitby Ellsworth, a chromium plater who has performed more than 30 306A tests, will discuss areas where each of the two methods may have some advantages over the other, and will provide some overview and organizational materials for anyone wishing to perform his own 306A sampling.
· 306A Method-Full Demonstration of Sampling Train & Methods
Frank Clay, U.S. EPA, Durham, NC
Frank Clay, the developer of the 306A chromium sampling method, will provide a detailed review of this new method, as well as the procedures that need to be followed in performing it.
Session Chairman: Whitby Ellsworth, National Chromium Company, Inc., Putnam, CT
8:30 a.m.-Hard Chrome Plating Tank Ventilation Technologies
Thomas E. Miles, Conserve Engineering, Laguna Beach, CA
In today's regulatory climate, one of the most important decisions facing the hard chromium plater is the selection of tank ventilation technology. This decision has far-reaching effects, such as: Compliance with EPA, OSHA and fire codes; health risk exposure for all employees; size, cost and efficiency of emission control equipment; and operating costs relating to energy, water consumption and chemical additives. Most chromium plating ventilation systems operating today do not comply with current OSHA design standards. OSHA standards will be described and compared to ACGIH and other industrial ventilation standards. Design and operating parameters for various ventilation technologies will be discussed and compared, including lateral exhaust, push-pull, covers and enclosures, and chemical mist suppressants.
9 a.m.-Regulatory Update
William Sonntag, AESF/NAMF/MFSA Government Relations, Washington, DC
9:30 a.m.-OSHA's Reduction of Permissible Exposure Level (PEL)-The Outlook for Action in 1996 William Sonntag, AESF/NAMF/MFSA Government Relations, Washington, DC The Occupational Health and Safety Ad-ministration (OSHA) of the Department of Labor plans to propose reduction of the current chromium permissible exposure limit (PEL) to one of the lowest in the industrialized nations. It is believed that OSHA is considering a PEL proposal of 0.5 mg/m 3 to 1.0 mg/m 3 . OSHA is under great pressure from the Public Citizen's Health Research Group and the Oil, Chemical and Atomic Workers International Union to lower the PEL from the current allowable ceiling limit of 100 mg/ mg 3 (micrograms per cubic meter as chromic acid) to an 8-hr time-weighted aver-age (TWA) of 0.5 mg/mg 3 as hexavalent chromium. The primary adverse health effect under consideration is lung cancer.
This presentation will discuss industry activities regarding this rule, including actions taken by the Joint Government Relations Program since 1994, anticipated projects to develop cost, exposure and technical data for the industry and the anticipated timetable and actions of OSHA.
10:30 a.m.-A Perspective on the Changing Chromium Air Emission Standards
Thomas E. Miles, Conserve Engineering, Laguna Beach, CA
Eight years ago, California adopted chromium emission standards that demand control efficiencies of 95 to 99.8 percent for hard chromium plating facilities. The current EPA MACT standard demands control efficiencies on the order of 98 to 99.9 percent for large-sized hard chromium plating facilities. Within eight years, EPA is required to implement risk-based standards that will demand control efficiencies on the order of 99.99 to 99.999 percent. Several states have already implemented emission limits comparable to the future EPA standard. Control technologies capable of meeting current and future emission limits will be described and compared. The case history of one California company that adopted a goal to achieve "near zero" emissions to meet future regulations will be described in detail. Equipment selection criteria, implementation costs, operating costs and test results will be presented.
11 a.m.-Conducting Surface Tension Measurements for Compliance with Chromium MACT Standard
Joelie Hill, Scientific Control Laboratories, Chicago, IL
Conducting surface tension measurements to consistently meet 45 dynes/centimeter is a compliance option for decorative chromium plating facilities under the U.S. EPA's National Emission Standards for Chromium Emissions (the MACT Standard). It is important to understand the various techniques and procedures for measuring surface tension in order to find a suitable method for your facility. This paper will cover methods with tensiometers (DuNouy ring and Wilhelmy plate), stalagmometers, capillary tubes, and various other methods. Cleaning, calibration and recordkeeping procedures for all methods will also be covered.
Session Co-Chairmen: Myron Browning, CEF, Matrix Technologies, West Hills, CA, & Steve Schachameyer, Eaton Corporation, Milwaukee, WI
1 p.m.-Advances in Decorative Trivalent Chromium Plating
Nabil Zaki, Frederick Gumm Chemical Company, Inc., Kearny, NJ
For the past 15 years, the shielded anode concept made it possible to use a stable non-halogen-type electrolyte plating solution to great advantages to the plater: High tolerance to metallic impurities, a light chrome deposit and high temperature applications. A new insoluble anode has now been identified for use with the same electrolyte. The new anode is used in direct contact with the solution with no generation of hexavalent chrome, while maintaining all the advantages of the shielded anode process. This paper will review the properties of the new an-ode and the results of 12 months of field testing.
1:30 p.m.-Hard Trivalent Chromium Plating: New Improvements & Results
Dr. Patrick Benaben, E.N.S. Mines, Saint-Etienne, France
Results will be presented on hard, thick chromium deposits obtained from an aqueous trivalent chromium bath by chemical reduction of hexavalent chromium with methanol alcohol. At a thickness of 100 mm, these deposits have a hardness of about 1000 Hv/100g and the deposition rate is 3 mm/mn at 80 A/Dm 2 . Microhardness obtained on thermal treatment of these chromium layers (400 °C to 700 °C) will be compared to that of hexavalent (sulfate and fluosilicate) baths. Results will also be presented on the chromium-nickel multilayer composite deposits obtained by the single bath method.
2:30 p.m.-A Review of Decorative Trivalent Chromium Electroplating
Dr. Donald L. Snyder, Atotech USA, Inc., Cleveland, OH
Over the last 20 years, trivalent chromium electroplating has been shown to be an environmentally friendly and productive process when compared to hexavalent chromium plating. The factors contributing to this success will be discussed.
3 p.m.-Hard Chrome Plating & Alternatives: How, When, Why &Where?
George Nichols, Mike Graham & Keith Legg, BIRL, Northwestern University, Evanston, IL
There are now various viable dry-coating alternatives for replacing electrolytic hard chromium (EHC) plating, but because none of them is universal, there are many applications in which EHC remains the most cost-effective technology.
This paper will discuss which re-placement options are best for certain applications, and what considerations should enter decisions on whether (and with what) to replace EHC. Where EHC is to be retained, there are now technologies available to reduce its environmental impact, and these will be discussed.
Session Chairman: Dr. Kenneth R. Newby, Atotech USA, Inc., Somerset, NJ
Open question-and-answer period; expected to run approximately one-and-a-half hr.
Open Forum 3:30 p.m., Friday, May 31