I. BASIC QUESTIONS:

1. What is a Platinised Anode?

Platinum is the most effective metal for any electro chemical process due to its current conducting property. However, Platinum also being the most expensive material rational utilization of the material for the greater benefit ensures economical solution in any nature.

Hence, a Platinum Anode is none but a rational utilization of platinum by coating or plating limited quantity on to a suitable substrate without compromising on the final product out put in the process.

Thus a Platinised Anode is a economical replacement for a Solid Platinum Metal.

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2. What are the different types of Platinised anodes available?

Platinum Anodes are available in the following forms:

a. Solid Platinum
b. Platinum foils cladded on to a substrate
c. EPMA – Electro Plated Platinum Anode
d. PLANMA – Platinised Niobium Metal Anode (Thermal Deposition)
e. PLATMA – Platinised titanium Metal Anode (Thermal Deposition)
 

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3. What are the difference and comparison between the Conventional Lead Anode and Platinised Anode?

Platinised Anode is a dimensionally stable Anode, which during the process does not disintegrate nor change the shape or size. Which is also highly corrosion resistance with a longer life and least maintenance.
 

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4. What are the advantages of Platinised Anode over Conventional Lead Anode?

The Platinised Anode is a most economical solution considering its life cycle, cost and the allied advantages such as Maintenance freeness, Eco friendliness, reduction in operating down time and zero bath contaminations.
 

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5. What are the different types of configuration/size/shapes/ Geometry available in Platinised Anode?

Platinised Anodes are available in any number of shapes / size and geometry to suit the customers plating bath / services such as Rods, Mesh, Tube, Plates, Rings, Wire in any geometries such as Coils, Cylinders, Pins, Baskets, Strips, Jigs, Fixtures, etc.,
 

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6. What are the different types of substrate available in Platinised Anode?

The substrate commonly used and which are readily available are

SS 316
Titanium
Niobium
Zirconium
Tantalum
Molybdenum
 

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II. ADVANCED QUESTION

1. What are the major application of Platinised Anode?

a. Electroplating : Gold Plating; Rhodium Plating; Silver Plating;
Paladium Plating; Ruthenium Plating; Platinum Plating; High speed Copper Plating; High speed Chromium Plating; Nickel Plating
b. Electrodialisis
c. Electrowinning
d. Electro Floculation
e. Water Electrolysis
f. Cathodic Protection
g. Electro Chlorinator
h. Heavy Metal Recovery
i. Persalt Electrolysis
 

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2. What are the operating parameters that a Platinised Anode can withstand?

Platinised Anodes in general can take the maximum current densities when compared to any conventional anodes available. However, its ability to withstand electrolytic media depends on the substrate used.

For example Titanium is most suitable as a substrate material for baths containing chloride, Low sulphuric, sulphate, cyanide, etc.,

Niobium is ideally suitable for baths containing fluoride

Zirconium is ideally suitable for high sulphuric baths
 

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3. What is the life of Platinised Anode?

The life of Platinised anode is determined by various operating parameters such as the current density, bath composition, temperature, plating duration, MOC of the component being plated.

However, based on the past experience TiTaN will recommend the life of coating on a case-to-case basis subject to availability of all operating parameters.
 

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4. What is the process of manufacturing platinised anode?

The process of Platinised Anode manufacturing can be categorized as below:

a. Substrate fabrication
b. Degreasing of the substrate by conventional method
c. Chemical cleaning of substrate
d. Electro deposition of platinum on the substrate
e. Final cleaning and finishing
 

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5. What is the process involved in recoating of Platinised anode?

a. Used substrate cleaning for all contaminations by mechanical method
b. Used substrate repairs
c. Degreasing of the substrate by conventional method
d. Chemical cleaning of substrate
e. Electro deposition of platinum on the substrate
f. Final cleaning and finishing
 

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6. What do you mean by Platinum Coating and Plating?

Platinum plating is a process wherein the platinum is deposited on to the surface of the substrate by means of electrolytic process.

Platinum coating is a process wherein the platinum is deposited on to the surface of the substrate by means of a Thermal decomposition process.

In both cases the decomposition of platinum is in a metallic form. However, in coating process the decomposition is more porous where as platinum process is pure and uniform.

In case of coating process the platinum loading on to the surface has limitations of a maximum of 3 micron.

In case of a plating process the loading of platinum can be achieved upto 100 micron and above.
 

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7. What do you mean by thickness of plating

The platinum plated on to the surface can be controlled in the plating process by various parameters to meet the required amount of platinum loaded on to the surface.

By thickness of coating, we mean the quantity of platinum being deposited on to a fixed area of the substrate. Example grams / Sq. mtr of thickness mean loading of platinum which is calculated by stockiometric method and also can be established by X-Ray Diffraction.
 

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8. How do you measure thickness of plating

The plating thickness is measured by using a well established Stockiometric Method. However, for large volume contracts random sampling is done on the surface by X-ray diffraction Method.

The X-Ray Diffraction method of establishing the thickness of plating being an expensive option is carried out in TiTaN every quarter on random sample to reconfirm regularly the stockiometric method adopted.

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III. APPLICATION SPECIFIC QUESTION:

Hard Chrome Plating

1. In a Hard chrome plating what kind of substrate has to be used?

For most decorative Hard chrome plating
substrate used : Titanium Substrate

For other Hard chrome plating without
Any fluoride content in the bath : Titanium Substrate

High speed Hard chrome plating upto
60 mgs/ltr fluoride content : Titanium Substrate

High speed Hard chrome plating above
60 mgs upto 500 mgs / ltr fluoride
Content : Niobium Substrate
 

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2. In bath containing fluoride what kind of substrate can be used for the anode?

As explained above for baths containing fluoride up to 60 mg / ltr Titanium substrate can be used. However for baths containing more than 60 mg / ltr upto 500 mg / ltr Niobium is most suitable.

3. What is the period of Anode cleaning required in a hard chrome bath?

The Anode cleaning is limited to periods when there is a increase in voltage. No routine cleaning is required.

In case of conventional lead anode, it is more frequent due to the fact that lead chrome gets deposited on to the anode surface thus forming passive layer / affecting the efficiency of the anode performance. However, in case of platinised anode this effect is substantially reduced and a cleaning period for a continuous operating plant can be evolve with 6 months cycle.

During non-operation of the bath it is advisable to clean the platinised anode before reuse in the process.

Platinised anode does not require regular cleaning when in continuous operation.
 

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4. What is the guarantee offered for the anode performance in a hard chrome plating bath?

Depending on the process and application the platinum consumption would be in the range of 0.002 mg/Amp hour to 0.006 mg/Amp hour.
 

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5. Dos and Do not of using a platinised anode in a hard chrome bath?


DO’S

Ensure no loose connection to the Electrode terminals
Ensure proper Electrode gap and avoid any short circuit
Ensure the bath temperature doesn’t exceed 70o.
Always clean the platinum anode if not operated more than 8 hours
Ensure the Rectifier use has a minimum ripple less than 1 %
Always maintain the bath condition as stipulated by n the OEM
Ensure cleaning only with dilute acid with nylon brush.

DON’T

Don’t increase the chromic acid content in the bath above as stipulated by the OEM.
Don’t operate anode in dry condition without the electrolyte
Don’t operate the electrode current density above the OEM recommended parameters
Don’t operate the cell above the recommended voltage, which in most cases would be 20 V.
Don’t operate the cell for even short periods say few minutes with loose connection, as the Same will detach the platinum plated.
Don’t operate anode with opposite terminal for long periods
Don’t use any mechanical means of cleaning such as wire brush and other hand tools.
Don’t do any mechanical operation / modification on to the anode geometry in the platinised portion.
 

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6. What are the environmental effect of using platinised anode?

Platinised anodes are the most Eco friendly anodes. In comparison with conventional lead anode, which are highly contaminating in nature and also after use the lead disposal is comes under various environmental pollution laws.