FAQs

What are the advantages of non-cyanide alkaline zinc and where it is running?

Advantages of non-cyanide alkaline zinc:

  • Completely eliminates the usage of health hazardous cyanides - is more eco-friendly - reduces load towards effluents.
  • Throwing power of this process is better than other zinc bath producing more uniform thickness distribution.
  • Offers more corrosion resistance deposit.
  • This process is running successfully in barrel for plating on cycle spokes at some places in North India e.g. M/s Hema Engg. - Dharuhera, M/s Avon Cycles Ltd. - Ludhiana etc. Also running smoothly at some places in vat in Chennai and Coimbatore.

I am presently using your Ginthox 558 and want to use trivalent chrome based passivation process. Can I replace it? If so, what is the process and how to implement?

Yes, you can switch over to trivalent chrome based blue passivation system, we have two different processes namely, Trichrome 1000 and Trichrome HB 2000. Advantages of both of these processes can be sited as under :

Trichrome 1000 : New generation Trivalent Chrome liquid blue passivation.Salient Features :

  • Free from ecological problems.
  • Excellent bluish finish.
  • Superior corrosion resistance.
  • Trouble free operation.

Trichrome HB 2000
Trivalent Chrome based thick blue passivation process for ultimate corrosion protection.

Salient Features :

  • Highbuild Blue Chromate process with more deposit thickness.
  • Free from hexavalent chromium ~ eco-friendly process.
  • Corrosion Protection more than 100 hrs. (As per ASTM B 117).
  • Meets European end of LVD.

For process implementation you have to prepare bath using Trichrome 1000 @ 30-50 ml/lit. which will provide deposit with moderate corrosion resistance. For higher corrosion resistance, you have to use Trichrome HB 2000 @ 150 ml/lit.

We are plating car accessories and using bright nickel chrome with 30mm deposit thickness. Our plated components quite occasionally get rusted. Can you suggest any remedies?

Use Multilayer nickel-chrome plating instead of single layer bright nickel. Choice of multilayer could be a combination of semi-bright and bright for duplex nickel or semi-bright, tri and bright for Triplex. Triplex nickel chrome is more popular in India. Recently, a microporous nickel flash layer is also designed to apply on bright nickel prior to chrome plating which further enhances the overall corrosion resistance.

To achieve good corrosion resistance it is also necessary to maintain the operating nickel baths with minimum levels of metallic impurities e.g. Iron, Chromium, Zinc, Copper etc. For any practical purposes, the permissible limits of these metallic impurities should be maintained as below -

  • Iron : 20 ppm (max)
  • Chrome : 5 ppm
  • Copper : 10 ppm
  • Zinc : 15 ppm

Apart from the above, filtration also plays very important role in plating. Choice of filter pump along with its flow rate is the limiting factor. Incorporation of our Hercules filter unit opens new dimension in case of filtration quality. Keeping all these parameters well in mind it is now possible to achieve higher CASS test life (60 hrs.) to the plated components.

I am a design engineer currently doing a case study at work for hard chrome plating problems as follows :

  • crazing effect (also known as 'chicken wire' cracking and snake skin effect)

  • pin holes

I would like to know what causes these problems and what effects they can have when pumping in oilfield applications. The material being plated is precipitation hardening stainless steel to AISI type 630 (17 - 4 PH) which has been heat treated to NACE MR-01-75. Please forward me any information you have.
I would say the problem most likely lies in improper pretreatment of the base material. Otherwise it could be a result of excessive heat at the grinder operation (which you didn't mention if was carried out). Both situations may lead to crack patterns. Pitting, on the other hand, can only come from previous pinholes too small to be noticed, cleanliness of surface or lack of filtration before and during process. Most chrome platers are used to reverse etch conventional steel parts then forward plate them. This cannot be done with most SS as they will become passivated during reverse and will not produce good adhesion. They have to be activated in a special highly acidic formula.

We are a metal finishing chemical supplying house in India. We are interested to know the under coat for hard chrome plating on carbon steel/SS304 which can withstand in sea water. The Component are used for drilling oil & gas in offshore platform. Kindly give the guidelines which undercoat is most suitable under this severe corrosive condition. Also indicate coating thickness of undercoat. We have already tried with nickel(150 micron)+new generation chrome 150 micron(microcrack chrome) & different heavy thickness of S.B nickel + chrome (micro cracked) but failed to withstand Requirement is two months withstand.

Better than nickel would be electroless nickel but it is difficult to apply chrome on top of it, specially thick hard chrome. Have you checked the porosity of your first nickel layer? It sounds like 150 microns (0.006") of pore free nickel should be enough. Another possibility, if scratch or impact resistance is not a problem, would be to start with alkaline copper (25-50 microns), then acid copper (25-50 microns), then your nickel + chrome plating.

Yes it can be tricky, But not hard, as with most plated deposits. It's what your process is and how you process your parts. You may have to find the correct activator or dwell times or the like.

How many microns can be deposited in G.W. Karatclad 2N 18 or G. W. Karatclad 3 N.

Generally Karatclad 2 N or 3 N are designed to deposit up to 5 m gold plating. For which you have to keep gold metal atleast 4 gm/lit.Lower metal may cause haziness and it also drops down the efficiency of the bath.

For heavy micron gold deposition which process to be adopted?

For heavy micron or latest trend of 1 gm gold deposition G.W. can offer Karatclad 4 N process.

In this process you can keep 12 to 20 gm gold metal/lit and you can deposit up to 25 to 30 m. The competitors cobalt base gold can be converted in to Karatclad 4 N.

How many colour in gold G. & W. can offer?

G. W. can offer more than 12 colours in gold flash. The series CGS or PTS with different alloy combination, you get the colour variation from rich yellow, green gold, pink gold, pale gold & many more. This process is suitable for real jewellery of lower karat, optical frames, hardware & other applications.

Which one is the process for rich 24 KT flash?

You can choose G.W. Auroflash 100 or Growel Addictive P &C. process. The Growel Auroflash 100 is having long bath. You don't have to replace the bath whereas, the ordinary bath available in the market you can choose Growel Additive P&C having rich 24 KT shade. You get better average in the gold bath with this process. But you have to remake the bath after every 2 bath turnovers. You can also use PTS 100 but it will be expensive around Rs.1/mg. deposition cost which is exactly 100% more than the normal process.

How many electrophoretic coatings are available with G&W?

We have basically two systems, one is Acrylic Electrophoretic and second is Polyurethane. Acrylic system is very popular in dye gold segment. The dye gold exactly resembles the flash coating gold colour having better life than flash. Economically it is cheaper than the flash gold. Recommended on jewellery, spectacles, lamp fitting, idols and various others. Apart from gold we have 14 different colours in this range. We promote two products for deposition.

- Clearlyte
- Growclear LB 25

Clearlyte is old product and already established in the Indian market, whereas, LB 25 is a new superior version having very good strength and bonding with the base metal or base coating.

In combination with Clearlyte, it gives rich yellow 24 KT shade.

The other product is Growclear HBC which is polyurethane lacquer it gives up to 25m thickness having 4 H to 5 H pencil hardness. It also passes 24 hrs. immersion water test. Basically recommended for hardware, bathroom fittings and guaranteed micron jewellery segment.

 

 

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