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A recently published paper by a senior staff on a leading American magazine was unclear about the electroplating terms, like covering and throwing powers. Many times, we see vague interpretation and wrong distinction on these terms.

Advint’s online electroplating training and E-book offers right definition, explanation of identical terms and concepts. So, I’ll abstain from offering an elucidation here and write on the effects and recommendations.

The supplementary purpose of this paper is to emphasize the importance of correct interpretation of underlying electrolysis mechanism, terms, concepts of electrochemistry and electroplating fundamentals.

The confusion on these terms occurs when one draws a literary meaning on these words, reads leading technical magazines and science journals, and listens to veterans in this field.

Dr. Samuel Glasstone’s An Introduction to Electrochemistry delivers the clearest definition of throwing power of an electrodeposition process.

To correctly understand the terms, deeply observe acid chloride zinc or Watts nickel plating and cyanide copper or cyanide silver plating processes. Careful analysis of these electrolytes using a Hull cell will make clearness of these terms.

Handbooks and electroplating books frequently cannot document and analyze all developments, and now and then it misconstrues the depth of progress in the metal finishing field.

Confidentiality and hidden knowledge within the industry is the reason for such limitations. This limits awareness of all electrolyte properties and their formulations options with benefits. Many large organization’s operating procedures and practices also deter the best ability of a process.

We recommend you to question, test and re-consider critical attributes and formulations, including the references of Advint’s e-book guide to get a model electroplating routine.

Why is it imperative to comprehend properly?

Choosing a suitable electrolyte and maintaining the concentration of anions and organics will enable us to:

1. improve product quality
2. improve deposition thickness with due consideration for product geometry
3. meet functional and customer criterions
4. improve process control
5. reduce cost associated with rework and under or over thicknesses
6. minimize or eliminate problem solving time
7. correctly comprehend fundamental electrolysis mechanisms

How can you learn the correct terms?

Advint’s virtual course E-book syllabus covers relevant electroplating terms and concepts.

We recommend referring authentic resources, test yourself by analyzing electrolysis and deposition mechanisms on various electrolyte formulations and metal deposits.

To the Point

In this short paper, we discussed why right construal of a plating term is important. We reviewed how to access the pertinent information and the reasons for confusions. A diligent comprehension of the terms will help advance the metal finishing capability to what it’s worth.

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Surface profile of the substrate, specifically surface activity and its receptivity to accept electroplating deposit, spontaneously determines the morphology.

A deposit with good morphology will possess an adherent deposit. There is a myth and inadequate science work related to surface profile and adhesion. A few sectors do well with improving surface activity, and a sector is vulnerable. This short paper intends to shine light, dissipate a myth, and suggest improvements with supporting information.

Cleaning Activation

It is a normal practice to blast a metal surface to improve cleanliness. This approach predates the 60s, when cleaner science had made minimal progress. Over the years proprietary plating supply houses like Atotech, MacDermid Enthone and Coventya had conducted extensive research and offer an array of cleaning products. We released a short paper explaining the importance of cleaning on April 1, 2019.

In the absence of an effective cleaning process, blasting the surface is pertinent. It is an important treatment method on applications where we require higher Ra values or unique aesthetic appeal. Rather, if one blasts a surface merely to improve adhesion, then it is time to debunk the myth! Now, I’ll back up the purpose with facts and information.

To get an adherent deposit the metal surface must be clean, active and receive nucleation (form a unimolecular layer) within the first 10 or 20 seconds regardless of the current distribution pattern. A spontaneous and uniform deposit formation is important. The critical nucleation time varies between substrates and the deposit element’s electrode potential.

A truly active surface allows effective nucleation.

A poor nucleation layer will disrupt crystal growth and cause re-nucleation of the crystals. This disruption leads to deposit non-coherence and inconsistency in physical characteristics, resulting in premature product failure. Impregnated blasted media is very difficult to obliterate the surface and in most cases leaves a residue, hinders nucleation or continuity and uniformity of the deposit. An electropolished surface address this concern and enables epitaxial or pseudomorphic growth when and where applicable. This surface possesses very low Ra values, are active and free from foreign materials. If it drives you to get the most adherent deposit, electropolished surface is one of the best means to achieve this endeavor.

Surface Profile Adhesion

A truly active metal surface can form a thick intermetallic layer and develop a single domain deposit morphology (columnar structure) through the process. A single domain columnar structure deposit will possess a distinct grain boundary.

This mechanism is not independent of process control. The author of this paper had conducted extensive research over a decade on this matter, and so did a few other scientists from our society during the 80s and till now. A deposit with an intermetallic layer forms the most adherent deposit. In order for a non-electropolished surface to form an intermetallic layer, it must possess an active surface. We know that an electropolished surface possesses lower Ra value, but we require more controlled studies to validate the relationship between the surface profile and adhesion. On this subject, good surface profile implies a clean, smooth and active surface.

Morphology Physical Characteristics

Most adherent deposits possess good morphology. A deposit with an intermetallic layer and undisrupted columnar structure will have greater than 20% improvement in physical characteristics such as hardness, tribology, and corrosion resistance properties.

Summary

Blasting is a valuable pretreatment method, but an ambitious applicant must recognize that residue left on the surface affects the deposit characteristics, and it is not a certain choice in pursuit of an adherent deposit. Electropolishing is not practical on many applications. Exceptional cleaning and activation are viable and important.

Accomplishing an intermetallic layer on all applications is an unreasonable expectation, but a clairvoyance can set that as an aim. This aim is akin to lean’s one-piece flow and six-sigma.

In short, be mindful of the relationship between activation, morphology and physical characteristics.

Notes:

Material scientists and electrochemists now and then use different terminologies when referring to the same concept. Some terms used in this paper are no exception.

I used material scientist as a substitute for metallurgist. The global technical community replaced the term metallurgy with physical characteristics in 2010.

You are welcome to post a comment or email with questions to adviser@theadvint.com if a concept is abstruse.

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This paper is about the Hawthorne effect, the obvious but not so obvious effects, and the necessity.

Electroplating, anodizing, electro-polishing and complex processes such as plating on plastics require leadership drive to advance operations and engineering performance, and sustain on the growth.

An exemplary leader sets the expectation, creates necessity, delegates responsibility and confirms accountability without micromanaging the trivial effects.

We can set a clear expectation on variables such as electrochemical variables, process yield, product flow, inventory management, employee and executive management engagement.

Hawthorne Effect

The Hawthorne effect is the improvement detected because of a noticeable observation of the process. In reality, it does not confine the effect to a process, rather it encompasses to an employee performance. In both cases, it is a top-down approach, but ends with a continuous observation from all levels. When a leader sets the expectation, consistently follows up, align the goals with his or her actions, and supports their team to succeed, the team would achieve operational excellence in the long term. Observation and commitment to improvement must include all critical key performance indicators (KPI’s).

Obvious but not so Obvious

In retrospection, every challenge we overcame and the opportunities for improvement would become obvious to us. But this is late, as by this time we would have non-conformances, cost infliction and customer dissatisfactions. It is prudent to detect the obvious challenges and opportunities in real time. Earlier the opportunities were present, but hidden. We miss as it is not obvious!

If I did not communicate, think about the current COVID-19 pandemic. The issue originated in December 2019 and peaked in China during mid-February 2020. If the issue was apparent to global leaders and commoners around January, would the consequences be the same?

Revealing the hidden challenges in actual time is the heart of your effort in improving effectiveness.

How to expose these challenges? What prevents us from reading between the lines? The answer is not simple. This would be contingent on the leader’s emotional intelligence, knowledge of the subject and availability of visual data and information on real time.

Yield Shadows Necessity

We can achieve metal finishing processes and business effectiveness by focusing first on necessity. One must focus on the necessity to perform, collaborate, and on satisfaction (employee and customer). Yield will shadow the necessity–big or small; it is for you to choose! Clear responsibility and unambiguous accountability are the means to achieve necessity.

An Idea in Brief

Electroplating and other metal finishing processes are complex, as we all know. Market and customers are demanding. Contingencies like the COVID-19 pandemic will subject job shops and captive platers to hardship.

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At these and regular times, being conscientious of the process variables, exposing the hidden opportunities on real time, and starting with a focus on necessity are three important steps to achieve effectiveness in the manufacturing operation.

On a metal finishing processing line, among many design factors, choosing a rectifier with correct technical specifications and capacity based on production capability is very important. Predicting a production capability on most lines on a long term, particularly for a job shop is tough.

However, a correct choice on the capacity of a rectifier and on technical specifications will turn errors to account on a process performance.

Besides specifications, cost of a rectifier, power consumption and automation capability are significant considerations for a meticulous procurer.

IGBT and SCR Rectifiers

There are two types of rectifiers – Insulated gate bipolar transistor (IGBT) switch mode and silicon-controlled rectifier (SCR) thyristor. SCR rectifiers are suitable for high voltage and high ampere applications, but IGBT rectifiers possess higher efficiency, greater power factor, higher resolution, faster response time and constant ripple. Ripple matters in a plating application with an SCR rectifier and on precious metals plating.

Using a rectifier at the lower end of its rated capacity affects the ripple factor. On some applications there will be a negative influence on current distribution and throwing power of the deposit. A few deposits are tolerant than others. Precious and other transition elements differ in this attribute. Much of them are because of price. At a sub optimal capacity combined with a poor specification, a rectifier can yield a deposit with defective morphology compromising adhesion and the physical characteristics.

Note: Ripple is not the only cause a compromise can occur on the morphology of a deposit. Among many other variables, Helmholtz electrical double layer effect has a substantial effect on the morphology with the continuity of the deposit.

Other than ripple, there are cost impacts. A client of Advint, about 3 years back, purchased a 25,000 amperes rectifier. On most loads they had applied ~ 10,000 amps and seldom they applied 15,000 amperes. And the applicator does not foresee applying 20, 000 amperes within the next few years. The tank volume and the rack capability do not support the calculation. In hindsight, the applicator could have saved by considering a lower ampere rectifier (written with the Applicator’s consent).

On high ampere applications, power consumption is an important factor. When the distance between shunt and electrode terminals are higher, power consumption (resistivity) and cost is high.

Automation and Digital Control

On automatic applications, metal finishing industry uses human-machine interface (HMI) and programmable logic controller (PLC) capabilities for a long time. These interfaces are useful for current density calculations, plating time, ampere hour (AHR) control and chemical metering or dosing system, though the options are limitless. All chemical variables in a process are not consumed by electrolysis, rather a few follows adsorption mechanism. On these cases the use of PLC’s ladder logic, count down or count up timer will help. The MODBUS RS 485 serial communication protocol is the standard now to monitor and control the system. When a rectifier possesses higher end capability, and we maximize utilization even on a manual application, an applicator can see an advantage in labour cost and process control.

Ensuring we do not overload a rectifier, can extend the life of the rectifier. A periodic preventative maintenance program will support the same cause.

A Brief Idea

This short paper has brought to light the advantages of IGBT rectifier and the use of HMI/PLC interfaces with MODBUS RS 485 serial communication protocol.

Due diligence on specifications and productivity planning reduces fixed and marginal costs, improves the quality and consistency of the coating (electroplating deposit and anodized layer) processes.

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Rhodium Plating Techniques | Advint Incorporated

This is the second year of short papers release. Last year, Advint released papers on cyanide ions, properties and behaviours of anions, trends within the groups and periods of the periodic table, electroless Ni and current distribution (primary and secondary), quality and management. A year ago, I wrote about electrode potential and electromotive force (emf). As an example, nickel and gold possess distinct electrode potentials, and so are their deposition mechanisms.

Reel-to-Reel Plating

Electronic industry regularly uses gold, tin, palladium, palladium/nickel and copper on a continuous reel-to-reel plating application. Similar to gold, tin and indium possess comparable properties and advantages. Tin, silver, copper, indium, and gold all possess good conductive property. Indium, a precious metal, we primarily use as an alloying material in plating applications, though they use it as a deposit by itself (without alloying element).

Palladium and nickel are neighbors in the periodic table. We consider palladium to be a precious metal and it also possess properties comparable with nickel. It is broadly used in electronics and jewelry industries. On many applications, palladium or palladium/nickel acts as a good undercoat (an intermediate layer). Palladium/nickel deposit is recognized for its cosmetics, and wear and corrosion resistance properties. The ratio of palladium and nickel in the deposit varies between 80 and 20 to 95 and 5, respectively. Palladium also gained prominence because of nickel release and nickel allergic properties. Upsurge in dominance of palladium is apparent when we look at the price of the metal in the market (today’s value – ~ USD 2213 per troy ounce).

Plating on Plastics (PoP)

The demand for nickel on other hand is rapidly growing in the automotive industry, particularly in plating on plastics applications. The wide acceptability of nickel is because of its refractory properties, though it does not belong to elements of the refractory group (periodic table). Nickel release and its allergic properties are an issue in certain demographics and on applications such as eyeglass frame, earring, necklace, ring, bracelet.

On PoP applications, plastic substrate preparation using a colloidal catalyst is one of the most important steps. On acrylonitrile butadiene styrene (ABS) plastics, it follows preparation of the substrate with electrolytic copper, nickel and chromium deposits. Among Ni use, electroless Ni is gaining wider acceptance in recent decades. The industry also now replaces hexavalent Cr with trivalent chromium.

Electrode potentials are distinct between hexavalent and trivalent Cr plating applications. The trend is the same on other metals such as Ni, Au, Sn, In, Cu and Pd. The properties are distinct not only because of electrode potentials but also because of transportation of ions and ionic mobility. Similar to chromium, ionic mobility of electrolytes of electro-polishing and anodizing are also less. This is one reason these require a very high DC voltage from the rectifier during processing. Note: A paper on rectifier is coming soon.

Summary

Different metals deposition mechanisms vary because of their electrode potentials and other properties like ionic mobility and concentration of metal ions.

Among many elements of reel-to-reel plating and PoP applications reviewed in this paper, Pd is used on both applications, and has gained significant recognition in the recent decades.

The recognition goes beyond plating applications.

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Creating a surplus is an implicit ambition of our real time contribution. The effectiveness of our drive makes a positive difference and offers maximum customer value proposition (CVP).

How do other sectors and manufacturing industries innovate and manage the fundamental concept of creating a surplus?

What surpluses mean?

Surplus is receiving more money than paying.

Surplus is an economic concept. This paper aims to strive beyond economic and financial prudence to improve and sustain on surplus. A profound strategy using traits like conformance, time management and decision making will help transition to a new approach.

We all have a procedure, a standard and a key performance indicator (KPI) to follow and observe. There is conformance and non-conformance. We are not referring to product conformances, rather we are discussing conformance trait of our mind. We use business improvement methodologies like ISO, lean and total quality management (TQM). Use or somewhat overlooking to use this trait properly is what defines as a route to the maximation of surplus.

Use of ISO standards and concepts in the beginning of growth stage is valuable. The standards used today must not hinder our ability to change tomorrow. A non-conforming mindset, swift decision making and managing time followed up with the revised adherence to ISO principles are one of the simplest means to realize CVP quickly.

What is the value of time?

Carl Sandburg wrote, “Time is the coin of your life. It is the only coin you have, and only you can determine how it will be spent. Be careful lest you let other people spend it for you.”

There is a plethora of lean tools. The uniqueness of lean is not in its tools but in its emphasis of culture. Adaptability and change combined with decision making is the most important means to the path of surplus.

Most use TQM on their work applications. On electroplating and plating on plastics applications, mere use of statistical tools is not sufficient. We recommend starting with 6 process development and control (PDC) tools and train ourselves to see the not so easily seen variations.

A New Approach in Brief:

Technology and finance sectors use information technology (IT) to boost the growth and analyze intricate information which human eye and mind rarely recognize. Sectors within manufacturing industry often use innovation to stay ahead of time. Use of standard and tools like ISO, lean and TQM produce fair CVP. To maximize CVP and create excess surplus, how we use the standard and tools matter the most. Ability to change, managing time and prompt decision making in real time will enable our organizations’ evolution to a new approach.

1. Leaders in technology and finance sectors who are adept at decision making do keep in touch with data and information on real time. Knowing the surroundings and being focused is a basis to be decisive and disruptive.
2. The leaders do not consider past performance or guide as a benchmark or a standard, respectively. We recommend leaders to examine and revise the standards and opportunities endlessly.
3. As Sandburg aptly put it, time is precious. Masters control the time and destiny.

We advise the electroplating management team to focus on surplus to coin money without difficulty.

Often you must consider originating a new approach with cognizance of conformance, decision and time.

Whatever that approach might mean to you and how and in what way it might be new, I’ll leave it in your capable hands!

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