keystone finish

Chemical treatments can remove high-temperature oxide and iron contamination. They also restore the steel’s corrosion resistance properties without damaging the surface finish. After the removal of organic contaminants, the normal procedures are commonly known as Pickle Passivation.

Pickle Passivation Methods:

Pickling is the most common chemical procedure used to remove oxides and iron contamination. Besides removing the surface layer by controlled corrosion, pickling also selectively removes the least corrosion-resistant areas such  as the chromium-depleted zones. Pickling normally involves using an acid mixture containing nitric acid, hydrofluoric acid and, sometimes, also sulphuric acid. Owing to the obvious risk of pitting corrosion, chloride-containing agents such as hydrochloric acid must be avoided.

Pickling with pickling paste/gel: Pickling paste (or gel) for stainless steels is suitable for pickling limited areas, e.g. weld-affected zones. It is best applied using an acid-resistant brush. Rinsing with water must be carried out before the paste dries. Even if, for environmental and practical reasons, neutralisation of the pickling paste is carried out on the metal surface, thorough rinsing with water is vital.

Pickling with pickling solution/spray: Pickling solution (or pickling gel in spray form) is suitable for pickling large surfaces, e.g. when the removal of iron contamination is also desired.

Pickling in a bath is a convenient method if suitable equipment is available.

Cleaning process

This procedure is carried out in a manner similar to pickling.

The passivator, applied by immersion or spraying, strengthens the passive layer. Because the passivator also removes free iron impurities from the surface, the treatment is more important after mechanical cleaning and operations involving a risk of iron contamination.

Electropolishing normally produces a surface that guarantees optimal corrosion resistance. It does not selectively remove areas of inferior corrosion resistance, but polishes microtips from the surface. The material gains a fine lustre and, most importantly, an even microprofile that meets extremely stringent hygiene requirements. For these reasons, electropolishing is normally used as a final treatment after pickling.

Passivation continues to be a very essential step towards maintaining the longevity of stainless steel parts by making the parts corrosion resistant. Pickle Passivation can make a huge difference in determining whether the critical machinery parts will perform at an optimal level or will experience failure during operation. Passivation needs to be done correctly however or it may actually end up inducing corrosion instead of preventing it.

While pretty much all developed industrial countries use the method of Pickle Passivation, there is no internationally recognized standards as to how the Pickle Passivation process works. One recognised fact however is to what everyone agrees on is to have an oxide film protection present on the surface of the stainless steel parts. This oxide film is so thin that is actually invisible to the bare eyes.

The Passivation process first starts with cleaning. It is crucial that industrial grease, other chemicals, dirt and debris get cleaned first before the passivation process starts. Adding oxide coatings on the stainless steel parts that is covered with dirt or grease will not do the metal any good. Even worse, it might even induce corrosion. It is therefore very important that the stainless steel items get thoroughly cleaned before the actual passivation process starts.

Once the parts are properly cleaned, they are then ready to be submerged in the acid bath. There are three commonly used method for this acid bath process which are nitric acid passivation, nitric acid with sodium dichromate passivation and citric acid passivation. Depending on the grade of the stainless steel parts and few other factors, a specific passivation bath process is selected.

This acid bath process is actually the main passivation process. However, the acid bath process being completed doesn't mean the whole passivation process is done. To make sure that the passivation process was successful, the stainless steel parts needs to go through the testing phase to make sure that the dirt, grease and debris were properly cleaned and the invisible coating form the acid bath was in fact properly applied to make the metals corrosion resistance.

All metal, even stainless steel can experience corrosion if there is any contaminants on the outer surface. These contaminants slowly eats up the outer body of the stainless steel and eventually goes inside the metal to ruin the entire metal over time. Pickle Passivation is applied to the outer surface the stainless steel metal to remove the contaminants so that the metal doesn’t corrode. Or better yet, the Pickle Passivation is applied to begin with so that the stainless steel metal doesn’t have any contamination built up at all meaning no more corrosion.

There are many stainless steel applications that require routine maintenance to make sure there are compliant with the laws as well as to make sure they are within safety guidelines. High rise office building, condominiums and apartments buildings for example have balconies that have stainless steel railings. These steel railings must go though routine maintenance every 10 or 15 years to make sure that they don’t rust and eventually break off resulting in serious injury or in worse case scenario, even death.

To make sure that no accidents happen and to be compliant with all applicable regulations, these rails go though routine maintenance of Passivation treatment. The rails are dug out form its base and acid solution is applied on the steel surface to remove the contaminants. Most common way of doing a Passivation treatment is by treating it with nitric acid solutions or in some cases nitric acid paste. This nitric acid solution or paste will remove any contaminants build up and add an outer layer on the surface to prevent future contamination build-up.

Proper care and process selection must be taken to identify the type of contamination and to make sure that the Passivation treatment is right to remove that specific contaminants. Since the Pickle Passivation process is done by using nitric acid which is a very strong form of acid, working with this acid must therefore be done with extreme care. Only skilled and trained professional should do the job of Pickle Passivation. If not properly done, the method or the process will not deliver the optimal result therefore might not even ensure proper safety when needed.

Pickle Passivation is not only used to remove the contaminants from the steel items that are already in use, it can be done on the stainless steel items that just came out of the manufacturing facility brand new. Once constructed, the steel will have areas that are permeable that eventually weakens the metal's resistance to corrosion and more vulnerable to external environmental elements. By removing the debris, dirt etc and giving the metal a Passivation bath removes all debris, dirt, oil etc that makes the metal permeable to external forces.

Mother nature puts its mark on everything. Rain, snow, water and other weather elements change the nature of pretty much anything. Metal parts degrade the most from the natural elements. Rust and corrosion are very common on metal parts so in order to improve the longevity of these parts, they need to be coated with corrosion resistant coating. Phosphate Coating is such coating that protects the metal parts by adding a layer on the top that is corrosion resistant. This type of coating protects the metal from natural elements so that the metal parts remain rust and corrosion proof.

Steel and other metals by itself exposed to mother nature has only limited lifespan. If left untreated or uncoated using Phosphate Coating, these parts start to show rust in just matter or a year or two. We all have seen those steel or iron rails that were so rusted that part of the rails started to fall off. We all have also seen machinery items where the steel items or the screwed made of steel started to rust. This creates a major safety issue as the rails will not serve the main purpose of protecting people or keeping people in. or the screws will not do the proper job of holding things to places.  

This is where Phosphate Coating comes handy. Once coated with Phosphate Coating, metal items don't suffer the rust or corrosion anymore making them last a long time. Not only this ensures the safety concern, this also eliminates the need to routine maintenance.

While Phosphate Coating adds in to the overall cost of the implementation, but it ends up saving money in the long run. Metals that are not treated with Phosphate Coating will need to go through routine inspection every few years ro so may it be every five years or every ten years. If the expected life of a machinery is fifty years, then during the course of ownership, there will be five or even ten routine inspection to make sure the machinery is performing to its optimal level without any sign of dangerous damage to it. Phosphate Coating can eliminate this routine inspection as we know once coated, these metal parts will not rust anymore. Not only a huge cost savings, but also removes a huge load off the shoulder as you will be worry free.

Phosphate Coating is typically used to make the metal corrosion resistant. The way the process works is by converting the surface of the where it is applied towards a nonmetallic and polycrystalline coating that has the manganese, iron, zinc and nickel phosphates. This process is utilized for the treating of individual metal or for a mixed production.

Aside from improving the corrosion resistance, the process of Zinc Phosphate Coating can help to improve the overall appearance of finished goods by creating a uniform black or gray appearance. The process is also a much cheaper alternative to painting or plating, especially when it comes to hidden metal parts.

There are lots of companies these days that provide surface treatment conditioners for zinc phosphating. These products are being used right before the coating stage without any rinse in between the stages which leaves a chemical deposit of conditioner. Such conditioner helps in the overall development of the proper phosphate crystals right at the metal surface. If used along with the Zinc Phosphate Coating, they help to promote excellent corrosion resistance and give you the chance to paint a highly decorative finish on day to day products like washers, refrigerators, dryers, air conditions, as well as office furniture which any consumer can greatly rely on.

A phosphate coating is a type of conversion coating created through a metal substrate that’s ferrous. The process of Phosphate Coating is done as a pretreatment before painting or coating and to increase the corrosion protection while improving the friction properties of some sliding components. In some instances, the phosphate coatings are being applied on threaded parts while coated with oil in order to provide anti galling properties as well as rust inhibiting characteristics.

The process of phosphating mainly relies to the basic pickling reaction which occurs right on the metal substrate if the process solution will come in touch with metal properties. The biggest benefit that phosphating can provide is excellent adhesion as well as corrosion properties. In essence, phosphate coatings are being used on steel parts but they are also being used for aluminum.

Pickle Passivation is one of the most critical steps when to come to maximizing the corrosion resistance of certain parts and components that were produced from the stainless steel materials. This can greatly make a difference in between the satisfactory performance and that of the premature failure in the production of these materials. When performed incorrectly, the passivation can result to corrosion.

Post Fabrication Method

Pickle Passivation is basically a post fabrication method used to maximize the inherent corrosive resistance of the stainless steel alloy rom where the work piece is being produced. It is not a treatment for scale removal or a coat of paint and there is no universal process on the precise mechanic of how the passivation will work. However, it is certain that the protective oxide film will be present right off the surface of the passive stainless steel. Such invisible film is very thin in size, and is in fact less than 0.0000001 inch in thickness and is thinner than a human hair.

A clean and freshly machined stainless steel part will then immediately acquire the oxide film coming from the exposure to the oxygen right in the atmosphere. Under certain conditions, such protective oxide film will fully cover all surfaces of such part.

Contaminants

In the actual practice of Pickle Passivation, certain contaminants like the shop dirt or particles coming from tools used to cut iron could be possibly transferred right off the surface of the stainless steel. In certain conditions, thin coating of rust could appear. Such is actually a result of the corrosion of the steel coming from the tool and not due to the parent metal. In certain cases, the crevice off the embedded particle of the steel material coming from the cutting tool or the corrosion products could lead to an attack of the part itself.

In the same way, small particles of the iron containing dirt could adhere towards the surface of the part. Even though the metal could appear shiny similar to a machined condition, the invisible particles of the free iron could lead to rusting off the surface after it gets exposed to air during the process of Pickle Passivation.

Exposed Sulfides

Pickle Passivation, also known as chemical descaling is just one of the various pretreatment steps used for preparing a metal product for further processing like passivation or electro polishing. Sometimes, it is also used to provide superior cleaning operation of the welded structures.

Before the picking is done, the heavy surface soil that has grease, oil, buffing compounds, some scale, drawing compounds, dye, heavy rust, tape, paint markings, adhesive residues as well as other foreign substances should be taken off completely. Such step will be accomplished with the use of solvent cleaning, alkaline cleaners, vapor degreasing, steam cleaning, ultrasonic cleaning, water jetting, and other mechanical cleaning procedures. Pre cleaning is not advisable if the oxide or scale is the only soil that is on the surface.

Corrosion and Pickling

Pickle Passivation is often done in order to remove the tightly adherent oxide films that results from heat treating, hot forming, welding, as well as other high temperature operation. Heat treatment or welding will often produce complex oxides which vary greatly in color. All of these oxides are usually being called the scale and should be totally taken off. This is the needed step required for Pickle Passivation.

Whenever possible, an alternative mechanical method may be needed. Methods such as shot peening, blasting, tumbling, as well as wheel abrading might also be done. Abrasives that contain iron must also not be used. In certain cases, pickling of the stainless steel is done in two ways, one is the softening of the scale and another is the final scale removal. Under pickling, over pickling, as well as pitting is often a direct result of the lack of control on the process variables that includes the acid concentrations, contact time, as well as solution temperature.

Passivation

Pickle Passivation consists of chemical cleaning, surface cleaning and degreasing. Such stage will allow the pickling and the passivation chemicals to come in close contact with the metal surface that needs to passivate.

The process of picking has allowed for the itching of the metal surface uniformly and is being controlled by itching. At this stage, the metal surface will be activated uniformly. It should remove all sorts of contaminants including the free ferrite as well as all sorts of scales. In addition, the passivation also helps to eliminate the corrosion susceptibility of the surface of metals and creating a uniform passive layer. The chemical surface conversion will t hen take place and the surface will become passive for further air oxidation.

Confirmation of Passivation

Cadmium electroplating is like an entire defense team, very strong and robust. It is a white colored metal that protects substrate like no other. It not only adds finish but it actually sacrifices the cadmium layer first before the substrate begins to corrode. You can use Cadmium electroplating to a lot of different substrates like steel, cast iron, copper, malleable iron and powered metal. Sometimes, cadmium plating appears to be in the color gold because of chromate conversions, this process is very commendable since it enhances the surfaces corrosion protection ten times fold. Other colors that you may fancy are black and olive.

Cadmium electroplating gives a one of a kind bonding surface for adhesives like those which are commonly used to aircraft manufacturing and is also quite preferred over others for marine manufacturing as well because of its well proven endurance from salt water corrosion. Cadmium plating has a lot of other advantages that will be beneficial for all types of metal manufacturers. This process creates superior solder ability, high conductivity, commendable galvanic coupling with aluminum and great natural lubricity. These are exceptional qualities on top of the fact that this method of plating really protects the substrate unlike any other from corrosion. Also, the properties mentioned are also proven beneficial for metal parts that are exposed to repeated assembling and disassembling like scheduled preventive maintenance of aircrafts. Cadmium plating also resist mold or bacteria growth and that’s why this has been critical to the aerospace industry.

Cadmium is normally applied through electro-deposition from cyanide or acid solutions in barrels. While true, this process can actually also be done through mechanical plating yet the most consistent and even method is really cadmium electroplating. This metal is actually a by-product of producing zinc. When it was discovered, it was a revolution since most metal industries started using protective cadmium coating since then. Today, the developed parts of the world has been benefiting enormously. This is very true since the annual consumption for cadmium coating has increased to one thousand tons.

The protection that cadmium plating gives is actually determinable since it is proportional to the thickness of the coating. It has been proven to be best used in rural and marine environments, additionally very resistant to alkaline substances and detergents. Cadmium can easily be formed like the substrate, effortlessly soldered without the use of corrosive fluxes. Since it also has high conductivity; the process also is very beneficial to the electronics industry.

Cadmium metal is potentially toxic to the environmental and therefore is under scrutiny. Cadmium plating is being phased out but is still widely used in applications like aerospace fasteners and in the field of military and aviation. Cadmium plating offers many technical advantages such as a strong and corrosion resistant surface even at relatively low thickness. It further offers softness and malleability in salt atmospheres. It has galvanic compatibility with aluminum and gives freedom from sticky corrosion products. Such properties make it the most reliable option for torquing plated threads and it can be dyed in many colors. It can hold up well as a paint base or a finished surface as it has good lubricity and solderability. Due to its adverse effects on the environment, cadmium plating can be replaced with gold plating. Even though both the metals share most of their properties, gold still cannot be used as a paint base due to its cost.

Uses of Cadmium Plating

Cadmium electroplating is useful in imparting corrosion resistance to metals like steel. Many industries use this coating in a great variety of applications as it has certain engineering properties that no other metal coating possesses. The aerospace industries specifically prefer cadmium plating as it prevents bimetallic corrosion that takes place between high tensile fasteners and alloys. The field of aerospace engineering regards cadmium electroplating very important for bolts, landing gears and fasteners and the like.

Health Warnings

Cadmium products are safe to use, handle and deposit normally, but under certain situations, it can present a potential health hazard. It is advised to keep in handy respiratory equipment and tools for ventilation when cadmium welding or heating products that have been electroplated with cadmium over 250 Deg C. The cadmium oxide fumes so formed are highly toxic and inadequate ventilation can be highly dangerous.

Coating Properties

• It provides long lasting protection to the underlying components of steel.

• The corrosion protection of cadmium typically is very predictable and proportional to its thickness. Cadmium electroplating thickness ranges between 5 and 25 microns.

• Cadmium has good resistance in rural and marine environments and alkaline conditions.

• It is a strong barrier against galvanic/bimetallic reactions between other metals like steel and aluminium.

• Repetitive dismantling is allowed and tightening torque gets reduced as cadmium coating has low friction coefficient. It also allows for the correct cutting of threads on nuts, bolts and screws.

• The valves and delicate mechanisms that are coated with cadmium have small particle volume and are not prone to getting jammed with debris.

• When it comes to maintaining dimensional tolerances, thin cadmium coatings are more appropriate for coating threaded components, screws or lids or nuts and bolts.

• Cadmium is as easy to form as is the substrate itself.

• Cadmium coatings have lower electrical contact resistance than steel coated with zinc. It has certain properties that make it easily soldered without using corrosive fluxes. This makes it important for electrical and electronics industries.

The most common form of electroplating is the silver plating which you are easily able to locate in the house when the ladies in the house start getting ready for parties and social functions, they put on the most inexpensive of the jeweler which might just seem to give you a hint of silver jewelry but in turn is not. That beautiful yet inexpensive touch is what we give through our Silver Plating services. We not only add a color of shine to the jewel of the business houses but also prevent it from getting corroded by the moisture in the air.

Our company has been silver electroplating the customer needs for long. Silver being a good conductor of electricity is highly used in the industries and therefore is a famous item among our clients who are into electronic goods. We have been able to satisfy thousands and thousands of customers who have had the electroplating needs whether it has been in the area of electrolyte or mordant in dyeing purposes.

Our customers have always meant a God for us. We have never settled out for nothing less than our customers satisfaction when it has come to delivering our services well to them. Our services are one thing that we have always given them within no time and this has made us famous in the vicinity. Lots of business houses have always been calling us every week for our Silver Electroplating services after they have seen our services in the businesses of their counter parts machines and other parts.

We give different options for silver electroplating to our esteemed customers. They can get three types mainly done- Matte plating, Bright plating and Semi-Bright plating. We tend to deliver the option of industrial plating on different electrical components, bus bars and bearing surfaces.

Silver shares a number of physical and chemical properties. They are soft, ductile and malleable. With the process of Silver Plating, the silver would crystallize in the face centered cubic configuration and will form a stable alloy with each other in various proportions. The silver material is also capable of resisting even the most common acids, except for the nitric acid. It is widely regarded as a coinage metal and it is for this reason why it is commonly used for various purposes, such as monetary, decorative, etc.

Silver Plating for Electronics

Silver Electro Plating is used mainly for electronics. Sometimes, the silver is being plated with copper since the electrical resistance of copper is usually lower. It is even more resistance at higher frequencies. The variable capacitors of silver are known to have the highest quality if especially if their plates are silver plated. In the same way, Silver plating even on solid silver cables are used for audiophile applications. But some experts will consider such practice of plating as poorly implemented which makes the result poorer than other copper cables with similar prices.

High Humidity Environment

Utmost care must be observed for parts that are exposed to high humidity environment. If the silver layer is porous and it contains several cracks, the underlying copper will undergo a rapid galvanic corrosion that will flake off the plating and then the copper will be exposed. This process is called the red plague. By history, the process of Silver plating is commonly used to provide a cheaper version of items that will otherwise be made of pure silver. Examples are candlesticks, cutlery, jewelry, etc. The earliest kind of the silver plated plate was the Old Sheffield Plate. In the 19th century however, new methods of production which includes Silver Electro Plating have been introduced. Another method that is used to apply a thin layer of silver to various objects, including glass, is to make use of the Tollens’ reagent on a glass and then add some Dextrose or Glucose. Afterwards, the bottle will be shaken and a reaction will take place.

Difference of Silver from Gold

With gold, the complex cyanides have a staple pH level value, but are low enough to be used for electrolytes that have no free cyanide. But in the case of Silver Electro Plating, the complex cyanide is unstable below neutrality which hydrolyzes to release the insoluble AgCN. As a result, the silver imposes a requirement that maintains at least free cyanide on the system and then sets a minimum operating level of pH for cyanide Silver plating solutions that is at least 8.0 to 8.5. In the general class of cyanide silver, you will find that there are several variations available. All are optimized toward anode corrosion and deposits brightness with great plating speed.

Electroless Nickel Plating is a plating technique where it uses nickel as a medium used for coating a metal. This technique is effective because it prevents corrosion than any other kinds of plating. Like any other metal plating’s, it also undergo a pre-treatment whereby it has to undergo series of processes to ensure the quality before it will be plated.

Pre-treatment process is the process to be conducted first before doing the nickel plating process. The material to be plated must be cleaned first to remove the unwanted soils. Failure to do so will result to poor plating. Each process must be followed by rinsing it two to three times to remove the chemicals which may be observed to the surface. De-greasing would then follow to removeunnecessary oils from surfaces. After it has been cleaned, it can now then undergo the nickel plating.

Electroless nickel plating is somehow more expensive compared that of the nickel plating. This is due to the meticulous process it undergoes. It needs to get the exact texture of the surface because the rougher the texture, the lower protection it gets from corrosion. The usage of strong acids during the pre-treatment process may lessen the corrosion protection. It is also a big yes to add greater amount of phosphorus content to achieve a good corrosion resistance but it is not advised to do a lot of baths because it can lower the corrosion protection level. Heating the metal is also a big no because doing such may again lessen the corrosion protection you want to achieve.

Large Nickel Plating refers to the nickel plating which involves large parts. When you think that plating small parts would be easy, in case of the large parts its not. We need to consider the five critical factors in plating large components. These are the part mass, volume, surface area, conductivity and chemistry.

Mass refers to the weight and sizing of the parts. It affects the sizing because too much and too less the level of corrosion protection.Volume can also be a reason for the misuse of the parts to be plated. The more parts to be bathed, the lesser corrosion level it gets. The surface area affects the corrosion protection. The rougher the surface, the less protection it can give. Conductivity determines the level of resistance. The chemistry ofthe pretreatment line also plays a vital role. If the processes have not been done properly and without proper application them you’ll undergo a dramatic scene. It is better to start right at the beginning to avoid complications in the further processes.

Electroless Nickel Plating, also known as the Electroless coating, is defined as the process of deposition of metallic coating through a controlled chemical reduction catalyzed by the alloy or metal that is being deposited. The Electroless coating process actually comes with various advantages over the Electroplating and other Large Nickel Plating procedures, which is why it is mostly preferred by various industries worldwide.

Advantages of Electroless Coating

So what makes the Electroless coating seem to be more advantageous over other nickel plating procedures? Read the following to find out. • Electroless Coating has virtually unlimited throwing power ability.

• It has little and sometimes no excess deposits at high points.

• It comprises with deposits of excellent chemical and physical properties.

• Electroless Nickel Plating has reduced hydrogen charging also called as the hydrogen embrittlement.

• It has the great ability to coat surface which is difficult and impossible to achieve through Electroplating and other Large Nickel Plating processes.

Disadvantages of Electroless Coating

The Electroless coating also comes with a disadvantage, although only one disadvantage is reported so far, and that is its very high cost. As compared to other nickel plating procedures, the Electroless Nickel Plating is a bit costly. Yet, given all the benefits that such process can give you, investing on it is definitely worth it.

Forms of Electroless Coating

Nickel plating is the most common form of Electroless coating. This comprises of a nickel phosphorus alloy with 2 to 10% P. The Electroless nickel often has an unusual quality of being amorphous in nature, instead of being crystalline in structure. These coatings comprises of high hardness ability, natural lubricity, as well as an excellent abrasion and wear resistance. With this, it is clear why a lot of industrial companies would choose the Electroless Nickel Plating over other types of nickel plating.

Applications of Electroless Coating

The most common applications for the Electroless Coating are pipes, valves, as well as the fasteners. The thickness of the coating will often range from 2.5 to 150µm, although most components that are used for engineering purposes are known to have a thickness of 50 - 100µm. The greater thickness is often required whenever rough surfaces are encountered during the process of coating.

The Electroless Nickel Plating is sometimes considered as an economical treatment that helps to improve the overall performance of carbon steel on a mildly corrosive environment. Among these are caustic solutions, trace acids, as well as chlorides. In situations where light wear might occur, the Electroless Coating is also a big help. However, it is a bit difficult to deposit the Electroless Nickel or some Chromium containing steels. The Electroless nickel will therefore be deposited on the internal diameter of a tubular component as well as other surfaces that are difficult to access.