DODUCO’s products for use in galvanisation include the following silver cyanides (cyanide salts of silver):

• Silver cyanide| AgCN
• Potassium silver cyanide | potassium dicyanoargentate | K[Ag(CN)]₂

Silver cyanide properties

Silver cyanides (silver salts of cyanide) are characterised by a very high purity and good pourability.

The 80.5% silver cyanide is a white, powder-like product that will not form lumps. Mixed with potassium cyanide at sufficient amounts will make it dissolve well in water.

The 54% potassium silver cyanide, also a white salt, forms fine crystals that will dissolve well in water even without any extra addition of potassium cyanide.

Both silver cyanide and potassium silver cyanide are mostly used to prepare and improve galvanic silver baths or pre-treatment electrolytes in galvanisation plants.

DODUCO’s products for use in galvanisation include the following cyanide salts of gold:

• Potassium gold cyanide | potassium dicyanoaurate| K[Au(CN)₂]
• Potassium tetracyanoaurate| K[Au(CN)₄]

The cyanidic gold salts by DODUCO are characterised by a particularly high purity and even structure.

Both the monovalent potassium gold cyanide (potassium dicyanoaurate) and the trivalent potassium tetracyanoaurate are fine-crystalline white salts with good pourability that are very well water soluble.

DODUCO’s gold cyanides are mostly used as galvanochemicals for preparing and improving cyanidic gold baths that are used in galvanisation plants to gold-plate less precious metals.

DODUCO’s products for use in galvanisation plants include the following cyanide-.free precious metal concentrates:

• RHODIOR® 2 | Rhodiumkonzentrat | Rhodium sulfate solution | Rh(SO₄)₃ x H2O
• Gold solution | Sodium gold sulfite solution | Gold trisodium disulfite | Trinatriumgoldsulfitlösung | Na₃(AuSO₃)₂ x H₂O

The previous metal solutions (rhodium sulphate solution and sodium gold sulphite solution) by DODUCO are marked by high purity. In application as precious surface coatings, e.g. when rhodinating or gold-plating. high grip resistance and brought discharge of the precious metal layer must be emphasized. Rhodium sulphate solutions are often used with other additives in rhodium baths.

DODUCO’s silver-pigmented conductive varnishes are liquid, solvent-containing, physically drying varnishes. Depending on the area of application (carrier material, drying requirements), there are mostly two types distinguished:

• Conductive varnishes on acrylate-resin basis and
• Conductive varnishes on nitrocellulose basis

At a silver share of approx. 40 % silver (exceptions are possible) in the form of silver powder or silver flakes from own production, DODUCO’s silver conductive varnishes are characterised by high electrical conductivities at low viscosities. The liquid conductive varnishes can be applied to the carrier materials by brush, roller or submersion. If a spray application is desired, the conductive varnish should be mixed with the corresponding diluent (information on the diluent is available on request). Drying takes place by evaporation of the solvents contained in the temperature range between 20-100°C (on demand, higher temperatures are possible as well).

The benefit of the silver conductive varnishes as compared to the pastes is in simple processing and quick drying. Furthermore, they have a strong, good adhesion to the base and very good electrical and thermal conductivity.

DODUCO’s silver-pigmented conductive varnishes are used in:

• shielding of electromagnetic waves in the area of electrical engineering and electronics
• Production of a contact in the area of electrical engineering and/or hobby electronics (e.g. electronic toys)
• Repair of conductor tracks / improvement of printed circuits
• Repair of heating conductors (rear window heatings)
• Repair of antennas
• Metallisation of non-conductive bases for galvanic further processing

The also physically drying silver-pigmented conductive pastes of DODUCO’s range have a much higher viscosity than the conductive varnishes. This is caused by higher shares of silver (approx. 60%) and use of polymer basic components for formation of polymer compounds / design of the polymer structure. The silver used in the silver conductive pastes in the form of silver powder or silver flakes is also from the DODUCO-internal production.

The silver-pigmented polymer thick-film pastes are characterised by good electrical and thermal conductivity as well as good adhesion and bending resistance while being highly flexible. The application of conductive pastes preferably takes place by screen printing, with selection of the mesh size varying depending on printing pattern, layer thickness and base. Drying and curing may take place in circulation air dryers, IR-dryers or special tunnel furnaces.

On remand, the silver-pigmented conductive pastes can also be adjusted to different processing techniques (e.g. pad printing). The chemicals required for this may be purchased from DODUCO on request.

The benefit of silver conductive pastes as compared to the varnishes is in the better adhesion to plastic bases as well as films. I spite of high demands by increased flexibility, the layers remain stable and retain their very good conductivity.

DODUCO’s silver-pigmented conductive pastes are used in:

• production of conductor tracks on membrane keyboards
• production of circuits on PCBs

In addition to silver conductive varnishes and silver conductive pastes, DODUCO also produces silver conductive glues. Silver-pigmented conductive glues are used to apply construction elements to different carrier materials with conductive contacts. The adhesive technique offers essential benefits as compared to soldering, since lower curing temperatures permit connecting even heat-sensitive parts to each other conductively. Additionally, the higher flexibility of the bonding improves ageing behaviour of the material/part.

DODUCO’s delivery range contains two types of silver-pigmented conductive glues:

• Single-component conductive glue
• Two-component conductive glue

Single-component conductive glues are ready-to-use systems with long processing times. Curing takes place within 15-60 min. at temperatures between 120-200°C. In two-component conductive glues, in contrast, are mixed directly before use and then must be processed speedily. The processing time is approx. 4 hours, depending on ambience conditions. Curing can be thermally sped up.

Silver-pigmented conductive glues are applied by screen printing or dispenser.

Special features of DODUCO’s silver-pigmented silver glues are:

• very good conductivity
• low-stress properties
• high strength
• good heat conductivity
• no solvents
• temperature stability

Similar to silver-pigmented conductive preparations, precious-metal-free, graphite-pigmented conductive preparations are also based on decades of experience in production. The close cooperation with the customer has enabled DODUCO as producer to develop a selection of precious-metal-free conductive preparations that cover a broad area of use.

DODUCO’s range of precious-metal-free graphite-pigmented conductive preparations includes:

• Graphite conductive varnishes
• Graphite conductive pastes
• Diluent

Packaging sizes of 1 kg product per unit have proven their worth for practical use. The diluents can be delivered in different amounts as well depending on your needs and upon request.

Both DODUCO’s graphite conductive varnishes and graphite conductive pastes are sold under the brand name of GRAPHAROL®. Both product groups are made conductive by the addition of a special graphite pigment. Thus, the product will often have enough conductivity and offer a cost-efficient alternative for precious-metal-containing products. However, if you have any greater requirements to the conductive layer, you should use a silver-containing conductive product.

Similar to the silver conductive preparations, graphite conductive preparations adhere well to many plastics and other carrier materials. The solvents contained permit quick drying even at low temperatures and simple processing.

The thinly liquid graphite conductive varnishes are usually applied by spraying or with a brush. More viscose graphite conductive pastes are recommended for screen printing. Additional of a suitable diluent (information available on request) permits variation of the viscosities as required.

Depending on the area of application (carrier material, drying requirements), there are mostly two types distinguished:

• Graphite preparations on acrylate resin basis and
• Graphite preparations on acrylate-polymer basis

DODUCO’s graphite-pigmented conductive varnishes und conductive pastes are used for/in:

• antistatic equipment of containers and tubes
• Heating and warmth conductors
• Production of high-ohmic printed circuits and contact bridges in PCB production
• Printing over silver conduction tracks to increase corrosion and migration resistance