Changes

Semi-finished contact pre-materials can be manufactured from solid preciousmetals, precious metal alloys, or precious metal containing composite materials.They are made in wire, strip, and profile form by known processing technologiessuch as extrusion and subsequent annealing and drawing or roll-forming. Theyare supplied following the manufacturer's internal standards usually related toDIN EN specifications for copper based materials. The most important materialsare two – or multiple material layered semi-finished materials with the contactmaterial bonded in its solid phase to non-precious carriers by cladding, brazing,or welding. The contact material can also be deposited on the carrier from the

Clad materials consist of two or more layers of different materials, the contactmaterial and the carrier, which are firmly bonded to each other. Depending onthe electrical requirements the contact material is mainly an alloy of gold,palladium, or silver based , while the carrier material are mainly copper alloys. Tobond these materials , various technologies are utilized, the two most importantones being described in more detail below.

During ''hot cladding'', the classic process, the materials to be clad areassembled into a cladding package in block or plate form, heated to about800°C and clad (or “welded”"welded") together under high pressure ''(<xr id="fig:Hot_cladding_of_pre_materials"/><!--(Fig. 3.3)''-->). At theinterface between the two materials , a non-separable bond is formed by eitherdiffusion of the reaction partners or in liquid phase by forming a AgCu eutecticalloy when an additional brazing alloy foil is placed between the two materials.Further processing is done by rolling with required annealing steps betweensubsequent thickness reductions. The disadvantage of this process is theusually limited short length of final material strips.

In the ''Cold Roll-Cladding'' process, the bond between the contact and carrier material is achieved by cold deformation of > 50% in one rolling pass (<xr id="fig:Cold roll-cladding of semi-finished strips (schematic)"/><!-- (Fig. 3.3 Hot cladding 4)-->). The high plastic deformation causes cold welding in the boundary layer between the two materials. To increase the quality and strength of prethe bond, a subsequent diffusion annealing is performed in most cases. This process is most suitable for clad semi-materials finished strips with thin contact material layers (&ge; 2 μm) and large strip length (schematic> 100 m).

[[File:Hot cladding *Typical configurations of pre-materials clad contact strips (schematisch).jpg|right|thumb|Hot cladding <xr id="fig:Typical configurations of pre-materials (schematischclad contact strips"/>)]]

In the ''Cold Roll*Contact materials <br />Ag, Ag-Cladding'' process the bond between the contact and carriermaterial is achieved by cold deformation of > 50% in one rolling pass ''(Fig. 3.4)''alloys.The high plastic deformation causes cold welding , Ag/Ni, in the boundary layer betweenthe two materials. To increase the quality and strength of the bond a subsequentdiffusion annealing is performed in most special cases. This process is most suitable forclad semi-finished strips with thin contact material layers (also Ag/SnO_{2 μm)} and large striplength (Ag/ZnO <br /> 100 m).

Fig*Carrier materials: Cu, CuSn, CuNiZn, CuNiSn, CuFe, CuBe et al. 3.4: Cold roll-cladding of semi-finished strips (schematic)

[[File*Dimensions (<xr id="fig:Cold roll-cladding of semi-finished strips (schematic).jpg|right|thumb|Cold roll-cladding of semi-finished strips (schematicDimensions"/>)]]

*Typical configurations of clad When specifying the contact stripsmaterial layer thickness it is recommended to use the minimum required thickness.

<div class="multiple-images"><figure id="fig:Hot_cladding_of_pre_materials">[[File:Typical configurations Hot cladding of clad contact stripspre-materials (schematisch).jpg|right|thumb|Typical configurations Figure 1: Hot cladding of clad contact stripspre-materials (schematic)]] *Contact materials <br /figure>Ag, Ag<figure id="fig:Cold roll-alloys., Ag/Ni cladding of semi-finished strips (SINIDURschematic), in special cases also Ag/CdO ">[[File:Cold roll-cladding of semi-finished strips (DODURIT CdOschematic), Ag/SnO_{.jpg|right|thumb|Figure 2} : Cold roll-cladding of semi-finished strips (SISTADOX), Ag/ZnO (DODURIT ZnOschematic)]]<br /figure><figure id="fig:Typical configurations of clad contact strips">*Carrier materials[[File:Typical configurations of clad contact strips.jpg|right|thumb|Figure 3: Typical configurations of clad contact strips]]kein text</figure> *<figure id="fig:Dimensions bild">[[File:Dimensions.jpg|right|thumb|Figure 4: Dimensions]]</figure>When specifying the contact material layer thickness it is recommended to use the</div>minimum required thickness. *Quality criteria and tolerancesStrength properties and dimensional tolerances of clad contact bi-metals arederived from the standards DIN EN 1652 and DIN EN 1654 for Cu alloys. Whenspecifying the width of the contact material layer it is recommended to use theminimum required value. All dimensions should be specified originating from onestrip edge.<div class="clear"></div>

The toplay process starts with a flat or profile – shaped contact material stripwhich is fed together with the wider non-precious carrier material and in mostcases an intermediate thin foil of brazing alloy into a induction brazing machine''(<xr id="fig:Toplay brazing with an inductive heating inline equipment (schematic)"/><!--(Fig. 3.5)''-->). An evenly distributed and reliable braze joint can be achieved this waybetween contact and carrier materials. The combined material strip is rather softafter the brazing process and re-hardened during a subsequent profile rollingstep. In this way different shapes and configurations can easily be achieved. Fig. 3.5: Toplay brazing with an inductive heating inline equipment (schematic)

*Typical configurations of toplay contact profilesbild(<xr id="fig:Typical configurations of toplay contact profiles2"/>)

*Contact materials <br />Ag, AgNi 0,15 (ARGODUR), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR),Ag/CdO (DODURIT CdO), Ag/SnO₂ (SISTADOX), and Ag/ZnO (DODURIT ZnO)<br />

*Carrier materials <br />: Cu, CuZn, CuSn et al.<br />

*Quality criteria, dimensions and tolerancesbild(<xr id="fig:Quality criteria dimensions and tolerances"/>)

Strength properties and dimensional tolerances of toplay profiles are derivedfrom the standards DIN EN 1652 and DIN EN 1654 for Cu alloys.

<div class="multiple-images"><figure id== Seam–Welded Contact Strip Materials "fig:Toplay brazing with an inductive heating inline equipment (FDR–Profilesschematic)===">Seam–welding is the process by which the contact material in the form of a solidwire, narrow clad strip, or profile is attached to the carrier strip by overlapping orcontinuous weld pulses between rolling electrodes ''[[File:Toplay brazing with an inductive heating inline equipment (Figschematic). 3.6jpg|right|thumb|Figure 5: Toplay brazing with an inductive heating inline equipment (schematic)''. The weld joint is]]created by simultaneous effects of heat and pressure. Except for the very small</figure>actual weld joint area the original hardness <figure id="fig:Typical configurations of the carrier strip is maintainedbecause of the limited short time of the heat supply. Therefore also spring-hardbase materials can be used without loss of their mechanical strength. The use ofclad toplay contact pre-materials and profiles allows to minimize the use of the costlyprofiles2">precious metal component tailored to the need for optimum reliability over theexpected electrical life [[File:Typical configurations of the toplay contact componentsprofiles2. *jpg|right|thumb|Figure 6: Typical configurations of seam–welded toplay contact strips and stamped partsbildprofiles]]Fig. 3.6: Seam-welding process (schematic) *Contact materials <br /figure>Au-Alloys, Pd-Alloys, Ag, AgNi 0,15 (ARGODUR), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CdO), Ag/SnO<subfigure id="fig:Quality criteria dimensions and tolerances">2[[File:Quality criteria dimensions and tolerances.jpg|right|thumb|Figure 7: Quality criteria dimensions and tolerances]]</subfigure> (SISTADOX), Ag/ZnO (DODURIT ZnO)<br /div> *Carrier materials <br /div class="clear">Cu, CuSn, CuZn, CuNiZn, CuBe et al.<br /div> *Dimensionsbild *Quality criteria and tolerancesStrength properties and dimensional tolerances of toplay profiles are derived from thestandards DIN EN 1652 and DIN EN 1654 for Cu alloys..

Contact profiles span a broad range of dimensions. Width and thickness are typicallybetween 0.8 – 8.0 mm and 0.2 – 3.0 mm resp. Special configurations, often definedas miniature-profiles or even micro–profiles can have awidth < 2.0 mm.

Miniature–profiles are mostly composed of a contact-bimetal material with the contactmaterial being a precious metal alloy or composite material clad, welded or coated byelectroplating or vacuum-deposition (sputtered) onto a weldable base material. Sincethese profiles are attached to carrier strip materials , usually by segment– or seam–welding to the base materials, materials with good welding properties such as nickel,copper-nickel, copper-tin, as well as copper-nickel-zinc alloys are used. The bottomsurface of the profiles usually has formed weld rails or similar patterns to ensure asolid continuous metallurgical weld joint between the profile and the contact carrier.

Contact profiles in larger sizes are often used for switching devices in the low voltagetechnology. For these , the contact layer mostly consists of arc erosion resistantmaterials such as silver–nickel, silver–metal oxides or the weld resistant silver–graphite. The brazable or weldable underside of the metal oxide or silver–graphitematerials is usually pure silver with also quite often a thin layer of a phosphorouscontaining brazing alloy applied to aid the welding process.

*Typical configurations of multi-layer contact profilesbild(<xr id="fig:Typical configurations of multi-layer contact profiles"/>)

*Contact materials <br />Au-Alloys, Pd-Alloys, Ag-Alloys, Ag/Ni (SINIDUR), Ag/CdO (DODURIT CdO), Ag/SnO₂ (SISTADOX), Ag/ZnO (DODURIT ZnO)<br />

*Quality criteria <br />Beause of the variety of configurations of contact profiles , usually the quality issues are separately agreed upon between the manufacturer and the user.<br /> *Dimensions and tolerances (<xr id="fig:Contact Profiles Dimensions and tolerances"/>)The thickness of the Au top-layer, which is sputtered for example, is between 0.2 and 5 μm, depending on the requirements. Tolerance of thickness is about &plusmn; 10%.

*Dimensions and tolerances <br /div class="multiple-images"><figure id="fig:Typical configurations of multi-layer contact profiles">The thickness [[File:Typical configurations of the Au topmulti-layer, which is sputtered for example, is between 0contact profiles.2 and 5 μm, depending on the requirements. Tolerance jpg|right|thumb|Figure 8: Typical configurations of thickness is about + 10%.multi-layer contact profiles]]<br /figure>bild<figure id="fig:Contact Profiles Dimensions and tolerances">[[CategoryFile:Manufacturing Technologies for Contact PartsProfiles Dimensions and tolerances.jpg|right|thumb|CategoryFigure 9: Contact Profiles Dimensions and tolerances]]</figure></div><div class="clear"></div>