Indium SLOTOSON MI 1930

INTRODUCTION

Indium SLOTOSON MI 1930 is an acidic electrolyte for the deposition of white, matt indiumlayers with a good solderability. The melting point of pure indium is 156 °C. The applicationfield of the surface is e.g. the coating of plug-in connectors and press-fit pins.

There’s a trouble-free operation of the Indium SLOTOSON MI 1930 electrolyte. Basically,only the metal content and the pH value must be checked and maintained constant. Theelectrolyte can be used for rack applications as well as for continuous plating lines.

The additives required for electrolyte make-up and operation meet the requirements of theRoHS (Restriction of (the use of certain) Hazardous Substances) EU Directive 2011/65/EUrelating to the limit of lead, mercury, cadmium, Cr(VI), polybrominated Biphenyls andpolybrominated Diphenyl Ethers.

The information in this data sheet is based on laboratory as well as practical experience.Figures quoted for operating limits and replenishment quantities are for guidance. Actualvalues necessary will depend on the components being plated (material and geometry), theirapplication and plating plant conditions.

TECHNICAL INFORMATION AND EQUIPMENT REQUIREMENTS

MAKE-UP AND OPERATING CONDITIONS

Product names

Requirements for a 100 litre bath

Make-up sequence for a 100 litre bath

All tanks and equipment to be used should be thoroughly cleaned prior to use. New unusedtanks, filtration equipment etc. or tanks and equipment should be leached for several hours(min. 24 h) with warm acidified water before use (20 ml/l Acid Concentrate FF).

 fill 80 litres of deionised water into the tank

 add 22 kg of Indium Concentrate FI while stirring vigorously

 add 1.5 ltr. of Additive SLOTOSON MI 1931 while stirring vigorously

 make up to final volume with preferably deionised water

 mix thoroughly

 check pH value

IMPORTANT：

The pH value should be checked and adjusted in regular intervals (depending onthe throughput).

The pH value in the new make-up depends on the concentration of the free acid in theIndium concentrate FI. After a short initial period, it raises by itself and should be thenmaintained at 2.0.

The passivation is ready for use when the operating temperature has been reached.However, it must be taken into consideration, that the optimum current efficiency is onlyachieved after a short initial phase respectively as soon as a pH value between 1.8 and 2.1has been reached. Until reaching this pH value an increased gassing and lower currentefficiency must be expected. The initial phase is according to our experience 5 Ah/l.

NB

Indium SLOTOSON MI 1930 is an acidic electrolyte. It’s absolutely necessary to observe thesafety measures applicable to make-up and handling this electrolyte (protective clothing,goggles, rubber gloves). Contact with the skin or the eyes should be rinsed with water for10 - 15 minutes. In case of continuous irritation, consult a doctor.

Concentrations and operating conditions

decrease pH value ↓: Acid concentrate FF

*     The upper values are to be aimed for high-speed depositions in reel-to-reel platingplants.

**    The optimum also depends on the plant and the flow.

NB

The operating range strongly depends on the indium content, the current density and the flowparameters.

Consumption and replenishment

Consumption is mainly due to drag-out and depends largely on the type and surfacegeometry of the parts as well as on plant operation.

Because of the rather high price for indium all countermeasures for reduction of drag-outlosses have to be taken. The optimum working temperature is 40 °C, which means loss byevaporation but can be compensated with rinse water of the subsequent rinsing station.

PROCESS SEQUENCE

Our field service and technical service department will be pleased to provide you detailedinformation on suitable process sequences or methods.

MAINTENANCE AND FUNCTION OF THE INDIVIDUAL BATH COMPONENTS

Indium Concentrate FI

Lack of indium is replenished by addition of Indium Concentrate FI, which contains 120 g/l ofindium. The content of indium can be analyzed. We are pleased to provide you with suitableanalysis methods upon request.

Additive SLOTOSON MI 1931

Additive SLOTOSON MI 1931 contains all necessary components for the deposition of a finecrystalline indium layer. Lack of Additive SLOTOSON MI 1931 results in an unevendeposition, which can be solved by additions in increments of 5 ml/l.

Operating temperature

The recommended working temperature is 20 - 50 °C, optimum 40° C.

IMPORTANT：

The pH value should be checked and adjusted in regular intervals (depending on thethroughput).

pH value

The pH value should be maintained between pH 1.8 - 2.1, optimum 2.0. Higher pH valuesresult in precipitation of indium as hydroxide. Lower pH values result in reduction of thecurrent efficiency. Therefore, it’s recommended to control the pH value regularly. Foradjustment Acid Concentrate FF should be used while stirring constantly.

Anodes

Indium SLOTOSON MI 1930 is operated with soluble anodes. The cathodic current efficiencyof Indium SLOTOSON MI 1930 is between 50 and 90 % and depends on the indium content,the current density, pH value, operating temperature and the concentration ofAdditive SLOTOSON MI 1931. The anodic current density is 100 %.

Activated carbon treatment

An activated carbon treatment should be performed as soon as the current efficiencydecreases noticeably. The treatment should be performed with 2 – 4 g/l of activated carbonat operating temperature/45 min.. Subsequently the content of Additive SLOTOSON MI 1931must be adjusted to the nominal value in increments of 5 ml/l.

TROUBLE SHOOTING

Fault finding chart

EFFLUENT

Legal regulations must be observed for disposal of the Indium SLOTOSON MI 1930.Different regulations normally apply for the additives and the ready-made electrolyte. Pleaserefer to section 13 of the appropriate Material Safety Data Sheet for disposal code andrecommendations.

The following detoxification sequence is only considered to be an aid:

Indium SLOTOSON MI 1930 doesn’t contain any complexing agents. Therefore, the metalcan be precipitated by a simple adjustment of the pH value to pH 7 - 8 as hydroxide.

SAFETY

Reasonable care is required when handling Schlötter chemical products. Only personnelspecially trained on working with chemicals should be deployed with their handling.

EC Material Safety Data Sheets must be made available to all personnel dealing with thechemicals to ensure they have all required information about product composition, hazardsidentification, first-aid measures, handling and storage, exposure controls, toxicological andecological information, etc. It is required to ensure the supply and use of suitable protectiveclothing and -equipment.