tin is frequently selected for the surface coating. Pure tin is the fi - PDF document

tin is frequently selected for the surface coating. Pure tin is the first choice as surface protection for all connector and stamped grid materials, not only because of its properties, but also the cost advantage over precious and semi-precious metals. Three main coating processes are used for the finish: hot dip tinning (which is mostly applied in Europe), electrolytic tinning and electrolytic tinning with a subsequent reflow treatment. An improved electrolytic reflow tinning process developed by Olin Brass, U.S.A., is new on the market and available at Prymetall from 2006 onwards. Electrolytic tinning with reflow treatment Advanced reflow tin and super thin advanced reflow tin Prymetall GmbH & Co. KG Zweifaller Str. 150 D-52224 Stolberg www.prymetall.com Tel. + 49 (0) 24 02-12 41-0 Fax + 49 (0) 24 02-12 41-2927 info@prymetall.com Electrolytic coated strips with tin (but also precious metals, such as nickel, silver or gold (on request selectively as well)) can be produced using subcontractors. Under these agreements the process is monitored and controlled at our works. Dimensions of 0.15 to 2.0 mm and widths of 10 to about 300 mm can be produced. The coating and intermediate layers are adjusted to suit the respective application. Electrolytic tinning with subsequent reflow treatment represents a special electrolytic tinning process: electrolyte anode + anode + cathode - component OV_SN_0511_E Hot dip tinned strips are characterised by a distinct intermetallic phase which is formed during the process and ensures that the tin adheres very well to the base material. It can therefore be considered a type of composite. The tin coating is pore-free and whisker formation is very improbable. There are no impurities from chemical additives from the pretreatment. Thus the coating does not outgas in heat treatment when subsequently processed. Prymetall GmbH & Co. KG produces hot dip tinned strips in thicknesses of 0.2 - 1.2 mm and widths of 10 – 400 mm in a facility which was modernised at the end of 2002. It is considered of utmost importance during the process that the cells in the strip pretreatment plant as well as the tin baths and all major process parameters are regularly monitored to ensure safe and high-quality tinning. In the hot dip tinning process the thoroughly degreased and activated strip is passed through a ladle containing molten tin with a temperature of between about 250 and 290 °C depending on the tinning requirement. After leaving the tin bath, the molten tin coating is usually levelled off to the required thickness by means of air knifes. In this way a thickness can be achieved of between 0.8 and 16 µm, a range that opens up a variety of applications. The typical range of coating thicknesses is shown in the following table together with their main properties. Hot dip tinned strips can be made of copper and all its alloys, such as brass CuZn5 to Cu Cu 3 Sn Cu 6 Sn 5 Sn Cu Cu 3 Sn Cu Cu 3 Sn Cu 6 Sn 5 Sn In contrast to Europe where hot dip tinning is most frequently practised, most of the strips coated with tin for the North American and Asian markets are produced electrochemically. Conventional chemical electroplating is therefore used. This process can achieve narrow coating thickness tolerances which amount to µ the strip width. The coating is even and can be matt or shiny. During electrolytic tinning the base material is not exposed to extreme temperatures which can be an advantage for heat-sensitive materials that are inclined to become soft during hot dip tinning (such as ETP-Cu). Likewise there is the possibility of multiple or selective coating and intermediate layers can be applied to improve the adhesive strength or reduce the diffusion from the base material into the coating. Electrolytic tinned strips are usually limited to coating thicknesses µ long precipitation times and resultant high costs. In addition, reports have been received about lower service lives of the punching tools compared with hot dip tinned strips. There is also a potential risk of whisker formation on electrolytic tinned strips. Hot dip tinned strips are characterised by a distinct intermetallic phase which is formed during the process and ensures that the tin adheres very well to the base material. It can therefore be considered a type of composite. The tin coating is pore-free and whisker formation is very improbable. There are no impurities from chemical additives from the pretreatment. Thus the coating does not outgas in heat treatment when subsequently processed. Prymetall GmbH & Co. KG produces hot dip tinned strips in thicknesses of 0.2 - 1.2 mm and widths of 10 – 400 mm in a facility which was modernised at the end of 2002. It is considered of utmost importance during the process that the cells in the strip pretreatment plant as well as the tin baths and all major process parameters are regularly monitored to ensure safe and high-quality tinning. In the hot dip tinning process the thoroughly degreased and activated strip is passed through a ladle containing molten tin with a temperature of between about 250 and 290 °C depending on the tinning requirement. After leaving the tin bath, the molten tin coating is usually levelled off to the required thickness by means of air knifes. In this way a thickness can be achieved of between 0.8 and 16 µm, a range that opens up a variety of applications. The typical range of coating thicknesses is shown in the following table together with their main properties. Hot dip tinned strips can be made of copper and all its alloys, such as brass CuZn5 to Cu Cu 3 Sn Cu 6 Sn 5 Sn Cu Cu 3 Sn Cu Cu 3 Sn Cu 6 Sn 5 Sn In contrast to Europe where hot dip tinning is most frequently practised, most of the strips coated with tin for the North American and Asian markets are produced electrochemically. Conventional chemical electroplating is therefore used. This process can achieve narrow coating thickness tolerances which amount to µ the strip width. The coating is even and can be matt or shiny. During electrolytic tinning the base material is not exposed to extreme temperatures which can be an advantage for heat-sensitive materials that are inclined to become soft during hot dip tinning (such as ETP-Cu). Likewise there is the possibility of multiple or selective coating and intermediate layers can be applied to improve the adhesive strength or reduce the diffusion from the base material into the coating. Electrolytic tinned strips are usually limited to coating thicknesses µ long precipitation times and resultant high costs. In addition, reports have been received about lower service lives of the punching tools compared with hot dip tinned strips. There is also a potential risk of whisker formation on electrolytic tinned strips. tin is frequently selected for the surface coating. Pure tin is the first choice as surface protection for all connector and stamped grid materials, not only because of its properties, but also the cost advantage over precious and semi-precious metals. Three main coating processes are used for the finish: hot dip tinning (which is mostly applied in Europe), electrolytic tinning and electrolytic tinning with a subsequent reflow treatment. An improved electrolytic reflow tinning process developed by Olin Brass, U.S.A., is new on the market and available at Prymetall from 2006 onwards. Electrolytic tinning with reflow treatment Advanced reflow tin and super thin advanced reflow tin Prymetall GmbH & Co. KG Zweifaller Str. 150 D-52224 Stolberg www.prymetall.com Tel. + 49 (0) 24 02-12 41-0 Fax + 49 (0) 24 02-12 41-2927 info@prymetall.com Electrolytic coated strips with tin (but also precious metals, such as nickel, silver or gold (on request selectively as well)) can be produced using subcontractors. Under these agreements the process is monitored and controlled at our works. Dimensions of 0.15 to 2.0 mm and widths of 10 to about 300 mm can be produced. The coating and intermediate layers are adjusted to suit the respective application. Electrolytic tinning with subsequent reflow treatment represents a special electrolytic tinning process: without endangering the contact resistance or solderability. From 2006 onwards, Prymetall’s customers will be able to take advantage of this new technology via our cooperation with a german subcontractor.