Thursday, October 30, 2014

Interest to Electroplating

If we asking why people interest to the process of electroplating even those people don’t know the chemistry or chemical process. Electroplating actually pure chemical engineering knowledge even the graduate from chemical engineering still don’t exactly the how to produce a good product using electroplating. On the plant it may combine with electrical engineering knowledge because of process need to regulate the electric current and voltage. Some reason why people want to know this process as follows:
  • Many product become look artistic after electroplating process apply, even this process need perfect step to get really good finished product.
  • Product become more expensive after finished with electroplating process, compare with the raw material itself.
  • Plastic can be finishing by electroplating and look very great and look like metal even the strong of this product is less than metal.
  • They still don’t know the difficulties on all the process to producing electroplating product include the regulation on clean production.

To make you more understand to the electroplating product you can overview on the pictures below:

Electroplating Product
White bright product is use electroplating with nickel and finished with chrome plating. Black or grey color may apply with nickel plating then with chromium plating but using different electric current. Gold color bright product is combination chemical processes in order get this art color. This process still being patented, so you can’t produce this kind product without buy the patent. You can buy tool kit to produce this but actually you also have paid the patent.

Tuesday, October 28, 2014

Electroplating Legal Patent

The extension of legal patent of certain patent is no longer needed, is this mean that we are no need permit to use the process of electroplating? May be because of many people in the world already use use this Chromium Electroplating Process without patent anymore or patent payment is not effective anymore. People don't want to pay of that certain patent process so that patent is no longer need to be extended.

Some important point on the patent you can read as bellow, so that you can develop your process in order can optimize of your electroplating process:

A plating process for plating chromium metal onto substrates is disclosed. The process uses a trivalent chromium plating bath with a sulfate and/or sulfonate matrix. The process also utilizes insoluble anodes. An addition of manganese ions to the plating bath inhibits the formation of detrimental hexavalent chromium ions upon use of the plating bath.

The present invention relates to a chromium plating method which utilizes trivalent chromium ions in the plating bath and insoluble anodes. An additive is proposed for the chromium plating bath which will minimize the creation of hexavalent chromium ions at the anode while the plating bath is being used.

The present of hexavalent on electroplating bath often disturb the formation of smooth layer on the metal. With additional of manganese ion like dissolve manganese metal into the sulfuric acid bath can help to prevent on the formation of hexavalent chromium ions.

Friday, October 24, 2014

Electroplating Process Flow Diagram

Electroplating Flow Diagram actually already discussed on this blog but still don't make a flow diagram as flow diagram. Flow diagram actually function for people want to know globally but don't want to know each detail process and what the chemical use and what the problem on each process. Flow diagram process usually just explaing to the new comer or to the visitor who want to know the whole process of electroplating or of each electroplating process such as; chromium plating, nickel plating, gold plating, silver plating, etc.

The process flow diagram in one plant as follows:

  • Strip:      Removal of old plating or paint
  • Rumble: Bulk processing of medium size parts, from burr removal to preplate or polish finish
  • Blast:      Glass grit or bead blast, from scale removal to preplate camera finish
  • Electroless Nickel: Special even coat on stainless steel, and non ferrous material
  • Chloride Nickel: Preplate coat on stainless steel
  • Zincate pre-coat: Coating to enable plating on aluminium and its alloys
  • Brighten: Chemical semi-bright processing prior to Anodise

Nickel and Silver Platting Calculation

A 0.500 amp current flowing for exactly one hour is passed through a solution of nickel (II) ions.

  1. How many grams of nickel metal will plate out?
  2. If this cell is hooked in series with another cell containing Ag+ ions (in series the same current passes through both cells), how many grams of Ag will plate at the same time?

First we need to know how much charge passed through the cell(s):
0.500 A x 3600 s = 1800 C

Now how many moles of electrons was that?

(1800 C x 1 mol e-) / 96500 C = 0.0187 mole e-

Since nickel (II) has a charge of +2, one atom of nickel will require 2 e- to plate:

0.0187 mole e- x 1 mole Ni / 2 mole e- = 0.00935 mole Ni

This is 0.549 grams
Since silver is plated by the same amount of charge, but each atom of silver requires only one electron to plate (Ag ions are +1), we should expect twice as many moles of silver atoms to plate:

0.0187 mole e- x 1 mole Ag /1 mole e- = 0.0187 mole Ag

Thus 2.02 grams of silver are produced. Note that the ratio based on charge affects the moles of silver and nickel. Their atomic masses influence the final mass plated.

Plating experiments are rather boring and this one is no exception. There is not much to do as the process takes place (especially if your calculator is recording the data...) and there is generally not much to look at. However, there is time for a fascinating diversion. You know from the activity series that zinc, which is above copper, will be displaced by copper in solution. The voltage for this process is 1.10 v as you saw in the previous experiment. The opposite process, zinc displacing copper is non-spontaneous. Or is it?

For many years chemistry teachers have done a demonstration in which they turn ordinary pennies into "gold". Traditionally the process has been done in a hot, very alkaline solution containing the ion Zn(OH)42- and some solid zinc. This combination of materials caused zinc metal to spontaneously plate on the copper. When the "silver" pennies were subsequently heated in a flame, the thin coating of zinc alloyed with the copper, producing yellow brass or "gold".

Recently a pair of chemists investigated this process more closely. Their report appeared in the Journal of Chemical Education. They found that the process was very different from what had been assumed. In fact, the very alkaline solution was not required at all! Copper placed in a heated solution of Zn2+ and a small amount of metallic zinc will become plated with zinc metal!! How is this? According to their research the process is driven by the alloying which occurs at the very surface of the copper. Due to thermal agitation in a heated solution, some zinc ions manage to work their way into the spaces between the copper atoms and form a very thin layer of brass.

The voltage for zinc metal plating on brass (as opposed to copper) is positive! Thus the "silver" appearance of the penny after heating is actually a type of brass (silver brass).
When heated in a flame, the silver brass is converted to yellow brass ("gold"). You can do this yourself, using the plating solution and some granular zinc.

Bring two of the shiniest (cleanest) pennies you can find. Place them in the beaker of solution provided on the hot plate and boil the solution. It takes about 10-15 minutes to plate a uniform layer of silver brass. Turning the pennies occasionally will help. When they are covered in silver brass, remove them and rinse in water. You can keep one "silver" penny and heat the other very carefully in a cool burner flame to change it to "gold". Too hot a flame will melt the brass coating, so be careful. This is just for fun, but it also points up the fact that not everything which we take for granted is happening they way we think. There are plenty of puzzles left to solve.

Saturday, April 12, 2014

Gold Plating Application

Gold plating is a unique surface with interesting yellow color. Beside the good color gold also have good properties to cover metal surface because it stand to corrosive weather and will not oxidized by water, other good properties of gold metal have electrical conductivity stays uniform over long periods resistance, good solderability, and when alloyed with cobalt, it has very good wear resistance. Gold is commonly used in electrical switch contacts, connectors pins and barrels, and other applications where intermittent electrical contact occurs.

Gold plating specification:
  • Type 1, with 99.7 % gold minimum, hardness grade A, B or C. Gold plating used for general purpose, high reliability electrical contacts, solderability, and wire wrap connection.
  • Type II, 99.0 % gold minimum; hardness grade B, C or D, A general purpose, wear resistant gold. But this equipment will not withstand to high temperature applications because the hardening agent in the gold plating will oxidize.
  • Type III, with 99.9 % gold minimum; hardness grade A only. Gold plating for semiconductor components nuclear engineering, thermo-compression bonding, and high temperature application.
Gold plating and Gold electroplating purity and coating thickness.

Any deposit of impurities can make difficult to solder, and for this reason high purity gold plating is preferred. Soldering requirements are best achieved when gold electroplating coating range between 0.00005 and 0.0001 inch (50 and 100 micro inches) thickness.

Gold Plating and Gold Electroplating hardness grades:

1. 90 knoop, maximum
2. 91 – 129 knoop, inclusive
3. 130 – 200 knoop, inclusive
4. 201 knoop, minimum