PLATINUM- a material for making Best Sellers.

This is the slogan used by Platinum Guild International's German office to market Platinum. Because of its unique physical and technical properties, Platinum is an interesting material to work with. However, in its pure state it is too soft to be used for many jewelry applications, and therefore needs to be alloyed with other elements to create a hard, workable metal. Over the years many alloy combinations have been developed and are in use today. Worldwide, the most common alloys have a purity of 950 parts per thousand.  Upon examining the contents of these alloys, one realizes that there is usually only one additional metal involved. The hardness of these alloys range from 65-150 HV (Vickers) which is not especially hard.

For this reason, DEGUSSA created Platinum Plus in 1987. This was a three component alloy and was demonstrative harder than the other two-metal Systems. In 1988, C. Hafner added a modified alloy with even a higher hardness under the name Platinum S. Shortly thereafter another variation of this alloy was introduced by Johnson Matthey-Brandenberger of Switzerland, Platinum XB SP 252. In 1998 Steven Kretchmer introduced Platinum StÔ and marketed it through Hoover & Strong in the US.

These alloys all have very specific properties and are all ternate alloys. Three metals are needed to create such an alloy. Even annealed and in a dead soft condition, these alloys are harder than the common ones.  Another very important difference and feature is the fact that they are heat-treatable.

This property makes it possible to use these alloys in specific applications.  Particularly in jewelry manufacturing, where the materials used are subject to high demands, heat-treatable alloys can be used by taking advantage of these special properties. These features are not necessarily in competition with conventional alloys, but serve as an additional tool to create a better product and to realize new designs.

The advantages of these alloys are:

  • For the finishing process:
    •A high basic hardness for the alloy
    •No loss of hardness during soldering/welding
    •Additional hardening after fabrication
    •Alloys do not grease
    •Ease of workability, filing, polishing
    •Easy and faster to polish
    •Good castability
    •Ease of milling

    For the product:
    •Highly dense pieces
    •Scratch resistance
    •Hollow jewelry with thinner walls possible
    •Filigree Platinum jewelry are possible
    •Reduced jewelry weight
    •Spring elements can be made at a better price
    •Springiness does not relax
    •New design and manufacturing possibilities
     
  • Disadvantages of these alloys:
    • •Oxidizing during heat operations such as soldering
      •Because of lower melting points conventional alloys cannot be used for welding
      •Welding solders cannot be used
      •Not useable for deep drawing

  • To protect jewelry parts from oxidizing, we recommend them to be covered with one of the available protective solutions, such as Cehaflux or Platin-Clean. Because of the fabricating techniques used, an oxidation on these pieces can not always be prevented completely. In this case it is possible to clean the alloy with a soft flame. This can also be accomplished in a kiln with a protective atmosphere. As matter of principle, there should be no more work done on a piece after it has oxidized, unless the surface oxidation is removed and the piece is shiny. Oxidation entering the metal trough drawing, rolling and such are very difficult to remove at a later stage.

    Conclusions:
    The hardening of Platinum alloys can be a great advantage to the jewelry production. Unfortunately, it is not being used to its full potential. This may be because heat treatable alloys are relatively new and not all jewelers are aware of them, or the technique of heat treating is not that well known.

    If one studies this subject, it becomes apparent that these methods and alloys make new jewelry designs possible and provide a wider spectrum in manufacturing options.

     

    • V6N5

     

    Heat Treatable Platinum for Jewelry
    Klaus Wiesner
    Product Manager
    C. Hafner Gold & Silver Refining Company

    This is an abbreviated version of the original work. For full technical details, please consult the original paper.