Shop our platinum and platinum-iridium marker band inventory online at
View AS9100 Cert | View ISO 13485:2019 (Limited Scope) Cert


Silverphos 5 Technical Data


Silverphos 5 and was developed primarily for use on copper, but its use has extended to other nonferrous copper base alloys. It is used extensively on refrigeration units, air conditioning apparatus, electrical conductors, copper and brass pipe fittings, and other copper and brass equipment.

Brazing Characteristics

Silverphos 5 is a copper rich, filler metal that is self-fluxing on copper by virtue of its phosphorus content. The self-fluxing property of this filler metals is effective on copper only. With copper-base alloys, such as brass or bronze, the joints should be fluxed. Silverphos 5 should not be used on nickel-base and iron-base alloys, as the phosphorus reacts with the nickel or iron to form brittle compounds at the interface of the joints. Silverphos 5, because of its higher phosphorus content, is more when heated rapidly to its flow point. Silverphos has less tendency to form large fillets or to fill poorly fitted joints.

Silverphos has a strong tendency to liquate (separation into low and high melting constituents) if heated slowly through its melting range, as normally occurs in furnace brazing. The results in leaving a “skull” of un-melted alloy behind may objectionable from the standpoint of appearance. In furnace brazing it is preferable to pre-place the alloys inside the joint where the skull is not visible.

Normally, the corrosion resistance of Silverphos 5 is of the same order as copper, but under certain conditions may corrode more rapidly. Silverphos 5 should not be used where the joints are exposed to sulfur compounds, especially in gasses or oils at temperatures above normal room temperature. As the corrosion by sulfur is cumulative, even very small percentages will eventually cause failure of the joint disintegration. Exposure to pressured steam can also result in accelerated corrosion.

Properties of Brazed Joints

The properties of a brazed joint are dependent upon numerous factors including base metal properties, joint design, metallurgical interaction between the base metal and the filler metal. 


Silverphos 5 alloy conforms to: American Welding Society (AWS) A5.8/A5.8M BCuP-3

Available Forms

Wire, engineered preforms, specialty preforms per customer specification, powder and paste

Compare With

  • AWS: BCuP-3
  • EN: CP 104
  • Lucas: Sil-Fos 5
  • UNS: C55281


  • Brazing Temperature Range High: 1595 F / 868 C
  • Brazing Temperature Range Low: 1545 F / 841 C
  • Liquidus: 1495 F / 813 C
  • Solidus: 1190 F / 643 C



  • Cu: 89%
  • P: 6%
  • Ag: 5%

The information and recommendations contained in this publication have been provided without charge & compiled from sources believed to be reliable and to represent the best information available on the subject at the time of issue. No warranty, guarantee, or representation is made by the Prince and Izant Company, Inc. as to the absolute correctness or sufficiency of any representation contained in this and other publications; Prince and Izant Company, Inc. assumes no responsibility in connection therewith; nor can it be assumed that all acceptable safety measures are contained in this and other publications, or that other or additional measures may not be required under particular or exceptional conditions or circumstances. The company and product names referenced herein are for identification purposes only. All trademarks and registered trademarks are the property of their respective owners.

Request a Quote Now!