Electroplating - tips, reviews and recommendations - Novohim

Copper plating

Admin — Wed, 26 May 2021 12:24:43 +0000

Copper is one of the ductile non-ferrous metals and has a pink color. Melting point 1083 C°. Copper plating of metal is quite popular and is used for various purposes:

Decorative and protective galvanic coatings that improve the adhesion of the main coating to the metal.
Electroplated copper plating is used when it is necessary to lap mating friction parts and reduce noise.
To protect steel during grouting.
Copper plating of parts is used for spark protection in specialized enterprises.

Methods and thicknesses of copper plating

There are two types of copper plating: electrochemical and chemical copper plating.

Copper is also applied to the plastic as an underlayer, and then, if necessary, chrome or nickel is applied to make the part have good reflective qualities.

Depending on the purpose, the thickness of the copper coating may be different.

For example:

when using copper plating as a sublayer for gilding or silvering – 0.3-0.5 microns< /li>
as an undercoat for multi-layer coatings requiring high anti-corrosion properties – 8-35 microns
solder undercoat – 6-36 µm
9-30 microns to reduce drag.

Copper Plating Electrolytes

The following electrolytes are used for the copper plating process:

alkaline
acid electrolytes
ammonia
Cyanide electrolytes.

The latter are quite poisonous and are used extremely rarely or in special technical processes.

Sulfate electrolytes

Sulfate electrolytes are fairly simple electrolytes and coatings that fully meet the requirements of regulatory documents. This process is often called copper plating with copper sulphate.

Composition of copper plating solution with sulfate electrolytes:

Copper vitriol/copper sulfate – 200-250 g/l
Sulfuric acid – 50-100 g/l.

Temperature of baths without stirring – 20-250 C° / Temperature of baths with stirring – 30-400 C°.

Cathode current density without mixing – 1-2 A/dm² / Cathodic current density with mixing – 3-5a/dm².

Limeda LT Glitter.

As a rule, to obtain shiny surfaces that do not require polishing, the composition of the electrolyte additionally includes a brightener for copper plating.

Previously, molasses, saccharin or chloramine B were used as a brightening agent for various processes. Nowadays, multicomponent brightening additives are made that are suitable for different bath compositions and have proven themselves in work.

A similar additive for copper plating is a multicomponent Limeda LT glitter . It is used in weakly acidic electrolytes in the amount of 5-10 g/l.

It happens that copper is applied to aluminum (aluminum copper plating) and its alloys or titanium alloys. For this, separate electrolytes are compiled and their composition is changed according to the technical process. However, if it is necessary to obtain a brilliant finish as a result, then Limeda LT copper plating brightener is also used for such cases.

See all electroplating additives here

Technical Novokhim specialists provide the necessary advice on your technical process, conduct laboratory analysis of bath samples and recommend reagents and gloss additives to obtain the perfect galvanic coating. Get in touch!

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Nickel plating

Admin — Mon, 17 May 2021 13:13:29 +0000

Description of the nickel plating process and its purpose.

As you know, the main cause and effect of the use of various galvanic coatings is metal corrosion. Corrosion of metal products brings significant losses during their operation. According to statistics, about 10% of metal products fail and fail precisely for this reason.

Protecting metal from corrosion is an essential task. Among the many ways to protect metal products, one of the most effective is metal and non-metal coating, which is applied by galvanic (electrolytic) method.

Properties of electrolytic nickel plating of a metal surface.

The electrolytic layer that covers the product must have the following defining properties:

durability

improved electrical conductivity

decorative, etc.

The nickel plating process is mainly used to obtain a protective and decorative coating. The nickel-plated surface acquires its decorative properties after polishing to a mirror shine, which lasts for decades.

It is recommended to use nickel coating as a protective coating with a copper sublayer. Because it provides a more non-porous layer. In addition, it allows to achieve greater efficiency of this process due to the use of cheaper metal.

In addition to its decorative properties, electroplated nickel plating also has high hardness and wear resistance. This allows the use of such products for the manufacture of measuring tools, for parts that will be operated in dry friction conditions.

Nickel plating can be of two types:

Electrolytic

Chemistry

The basis of chemical nickel plating is the reduction of nickel from aqueous solutions of its salts. On an industrial scale, precipitation is carried out from acidic and alkaline solutions.

Composition and working conditions of sulfate electrolytes.

Sulfate electrolytes are the most common and studied. However, they are very demanding in terms of compliance with the established operating conditions and the control of foreign impurities in the composition.

In addition to the mode, there are requirements for the very composition of electrolytes. The composition of the solution for nickel plating can mainly include:

nickel sulfate

sodium sulfate

magnesium sulfate

boric acid

sodium chloride etc

Moreover, the obligatory condition for observing the nickel plating technology is the following parameters of the bath:

Operating temperature

Current Density

PH value

Cathode current output

Stirring and filtering.

The durability of the work depends on the fulfillment of all conditions for proper operation
electrolyte and the quality of the finished product.

Shiny nickel plating.

Shiny nickel electrolytes also exist. When implementing this process, the goal is to apply a protective and decorative coating, which is achieved by mechanical polishing of the coating or the use of various brightening agents in the composition of the electrolyte. For example, Butyndiol.

There are also additional types of electrolytes that have not received such widespread use: boron fluoride, sulfamic, oxalic acid.

Components for the composition of nickel plating electrolytes, as well as brightening additives and other you can buy chemicals for nickel plating in Kharkiv from the assortment of the online store of chemical reagents of the Novokhim Company.

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How to choose a quality charcoal carburizer for carburizing parts

Admin — Mon, 15 Jul 2019 07:57:14 +0000

How to choose “correct” carb?

Charcoal Carburetor represents charcoal grains , which are saturated with carbon and covered with a film of barium carbonate.
According to GOST 2407-83 charcoal carburetor must meet the following criteria:

Name indicator Normal

Barium carbon dioxide mass fraction, %
20±2

Mass fraction of calcium carbonate, %, max 2,0

Mass fraction of total sulfur, %, max 0.04

Mass fraction of silicon dioxide, %, max 0.2

Mass fraction of volatile substances, %, max 7,0

Mass fraction of water, %, max 4,0

Size:
mass fraction of the remainder, %
-on a sieve with canvas No. 100, no more
-on a sieve with canvas No. 36, no less than
-per pallet, max
6,0

93

2

Where to use carburetor?

Charcoal Carb < span style="font-family: georgia, palatino, serif; font-size: 12pt;">used in the chemical-thermal treatment of steel, in the process of carburizing parts (carbon saturation). And it has a direct impact on the quality indicators of this operations. Namely:

to the depth of carbon saturation

its optimal saturation is up to 0.9-1% in the surface layer of the metal

hardness of cemented layer

abrasion resistance and many other carburizing results.

Barium carbonate as part of the carburetor ensures the formation of a gaseous environment during carburizing and is an accelerator of the whole process. And Calcium carbonate helps to eliminate the sintering of particles during heat treatment.

IMPORTANT! The main factor that determines the quality of a solid carburizer is the raw material from which it is made.

The carburetor must be made from charcoal GOST 7657-84 grade A of the highest grade. The mass fraction of non-volatile carbon in such coal is at least 90%. The granulometric composition is made up of grains of no more than 5% less than 12mm and no more than 5% of grains less than 25mm.

These sizes of coal provide good circulation of gases during grouting. In addition, in order to obtain such a fraction of coal, it is necessary to take commercial coal, the size of which is more than 25 mm, and crush it mechanically. Naturally, when crushing, a waste of about 30% is formed, which of course increases the cost of a high-quality carburetor.

Please note that it is at this stage that unscrupulous manufacturers reduce the price of your product. They produce a carburetor from charcoal screenings, which is essentially a waste product.

This screening represents charred twigs, pieces of bark, etc.. This is a violation of GOST 2407-83 normative documentation standards. And, of course, such charcoal will contain less than 50% carbon. But, on the other hand, impurities of ash and volatile substances that will create an unfavorable environment during cementation will be in excess.

How much does a GOST carburetor cost?

To calculate the price of a hard carb,

What is the danger of using a low-quality charcoal carburizer when grouting?

Firstly, it violates the main goals of heat treatment. As a result, we will not get the required hard hardened metal surface.
Secondly, the composition of the carburetor directly affects the rate and order of carbonation of the steel. The use of the “wrong” carburizer can lead to hardening cracks and flaking of the carburized layer as a result of carbon saturation of the surface layer of the metal too quickly. The depth of carbon penetration also depends on the activity of the carburetor.

A low-quality carburetor is more angular in shape and has a whitish coating on the surface. Quality charcoal carburetor has rounded grains without whitish coating, mouse color.

Also, you can use a high-quality charcoal carburizer 2-3 times, and a low-quality one will burn out after one carburizing cycle. Because it simply does not have enough carbon, as in a product that is produced in accordance with GOST from grade A charcoal.

Quality carburetor can be reused with 15-30% fresh hard carb.

Given that carburizing with a solid carburizer takes quite a long time from 8 hours. And, also, it requires high energy costs to heat up to 900-950 degrees Celsius. That saving on the carburetor can lead to the release of defective products and much more significant costs. Accordingly, those enterprises that use a charcoal carburizer according to GOST 2407-83 from grade A charcoal for grouting will benefit. They will receive both high-quality durable cemented metal surfaces and additional economic benefits.

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Galvanizing. Pros and cons of different galvanizing methods. Practical recommendations.

Admin — Fri, 19 Apr 2019 14:09:29 +0000

What is galvanizing?

Galvanizing is one of the most reliable and time-tested ways to protect metal against corrosion and improve the appearance of the product. Most enterprises, including private electroplating, use this particular electroplating method coatings due to the availability of the materials used and the quality of the resulting coatings.

What are the types of zinc plating?

Cold galvanized metal. What is cold galvanizing? – when a zinc alloy solution is applied to degreased metal by dipping or using a sprayer (brush), roller. The main disadvantage of this method of application is uneven coverage.

Hot dip galvanized. What is the difference between cold galvanizing and hot galvanizing? – During hot galvanizing, the metal is immersed in a hot zinc alloy. With a good preliminary preparation of the metal surface, a good quality is achieved. However, this method of coating requires a very high level of organization of production, huge volumes and expensive equipment. And a very significant minus is the high temperature of the working bath, up to +500 degrees C. The main task of these types is to protect the metal from corrosion.

Thermal diffusion galvanizing of metal – metal treatment with zinc in a vapor state. This type of galvanizing is quite expensive, but it has very high decorative and quality characteristics.
The advantages of this type of zinc coating are high productivity, low cost, coating uniformity while maintaining the size and shape of the product. As well as coating products of complex shape.

Galvanizing of metal – applying zinc to metal for account of the electrochemical effect. This method is suitable for all types of metal. The product receives a uniform shiny coating with a zinc layer thickness of 5 to 40 microns.

Galvanizing is widely recognized as the most effective. Therefore, let us dwell on it in more detail.

The galvanizing process takes place in baths filled with a special electrolyte composition. The quality of the resulting coating largely depends on the composition of the electrolyte.

There are two types of zinc plating:

Slightly acid galvanizing

Alkaline .

The most commonly used plating method in weakly acidic, simple galvanizing electrolytes. They feature a faster coating rate. At the same time, a high level of concealment and a good appearance are maintained. With this type of electroplating, bright additives and passivation are used to improve the appearance.

A bit of history. In the early 70s, Likonda multi-component gloss additives with components A, B, C and rainbow passivation Likonda 2A-T were used. A little later, they were replaced by gloss additives DHTI-102 and DHTI-104 with additional components that improve the quality and decorative properties of the coating.
Now they have been replaced by more modern and versatile BSK glosses.

Why use BSK glitter additives?

Combined use of BSK-A shiner paired with BSK-B enhancer is especially effective. The combined addition of these additives to solutions even with a low current density makes it possible to obtain fine-grained, more plastic and high-quality coatings.

Detailed description and application guidelines:< /span> BSK-A BSK- B

The final phase of galvanizing can be considered the passivation of the already obtained coating.

What is passivation for? Passivation enhances the strength of the zinc layer, increases the wear resistance of the coating, including at high humidity, exposure to acid fogs and salts. An important quality of passivation is to improve the appearance of the product. Although the main and most important advantage of this type of treatment is the protection of the zinc layer from corrosion.

To improve the decorative qualities of the coating, we recommend using iridescent or blue passivation.

Detailed description and usage guidelines : Rainbow Passivation Blue passivation

Novohim specialists will always help you choose the best type of brighteners and passivating additives. Application guidelines and samples are available upon request.

The Galvanizing. Pros and cons of different galvanizing methods. Practical recommendations. message appeared first on Novohim.

Name indicator	Normal
Barium carbon dioxide mass fraction, %	20±2
Mass fraction of calcium carbonate, %, max	2,0
Mass fraction of total sulfur, %, max	0.04
Mass fraction of silicon dioxide, %, max	0.2
Mass fraction of volatile substances, %, max	7,0
Mass fraction of water, %, max	4,0
Size: mass fraction of the remainder, % -on a sieve with canvas No. 100, no more -on a sieve with canvas No. 36, no less than -per pallet, max	6,0 93 2