High Conductivity, Oxygen Free Purity Copper for Electronic and Other Demanding Applications - OFE-Cu Certified Grade

OFE-Cu Copper Certified Grade

For electronic and similar applications we supply a very high-purity certified grade copper with a minimum electrical conductivity as high as 101.5 IACS. The total content of impurities is less than 40 ppm (0.0040%), no single impurity exceeding 25 ppm (0.0025%). To ensure high resistance to hydrogen embrittle ment, the maximum oxygen content is restricted to 5 ppm (0.0005%). The maximum total content of elements volatile in a vacuum at high temperatures (AS, Bi, Mn, Sb, Sn, Te, Cd, Hg, Zn), i.e. the impurities harmful in electronic applications, is 40 ppm (0.0040%). The content of each element, Cd, Hg, and Zn is max 1 ppm.

Manufacture

OFE-Cu Certified Grade is differentiated with respect to manufacturing, control and inspection from the OF-Cu regular grade (contact us for more details on this regular grade).

For the certified grade, only specially selected cathode copper is used, and ingots produced in the middle of the operation period - a period in which operations are most stabilised - are designated.

Advantages

The low content of the highly volatile elements such as phosphorus, lead, arsenic, sulphur, zinc, cadmium and mercury results in low volatility under high vacuum and makes OFE-Cu certified grade copper a metal of major interest to the electronics industry. It is readily joined by brazing or welding and is the superior grade of copper for electron beam welding.

OF-Cu copper is immune to embrittlement when brazed, welded or held at high temperatures in a reducing atmosphere. In addition, it is dimensionally stable when heated in hydrogen atmosphere.

The electronics industry uses glass-to-copper seals, which require an adherent oxide film on the surface. The oxide film may be rendered non-adherent with even a small amount of phosphorus, which is commonly used as a deoxidant. To prevent this, OFE-Cu certified grade copper contains less than 3 ppm (0.0003%) phosphorus.

Certified grade copper meets or exceeds the requirement of class 2 of ASTM F68 "Oxygen Free Copper in Wrought Forms for Electron Devices", NF A 53-100, alloy Cu-c2 and BS 3839 "Oxygen Free High Conductivity Copper for Electron Tubes and Semiconductor Devices".

Applications

OFE-Cu certified grade copper is the material for:

• Electronic tubes
• Magnetrons
• Vacuum circuit-breakers
• Vacuum capacitors
• Gaskets for vacuum apparatus
• Bases fpr semiconductors
• Large capacity generators
• Stabiliser sheaths for super-conductive cable
• Cryogenic applications
• Electron beam welding of copper
• Military applications

Quality Control

Due to a 100% microscopical inspection throughout the manufacturing process Luvata guarantee that each piece of the material has the metallographic contamination to either Class 2 or Class 1 in ASTM F68-77 and F68-82.

A full inspection according to ASTM B170 is made for each cut piece after casting, for each cut product after hot rolling or extrusion and on the final product.

A quench test for oxide adherence is made to ensure that the material is suitable for glass-to-metal seals.

Every delivery of OFE-Cu certified grade copper carries a test certificte which is a guarantee that impurites in the material are held below specified limits so that the electrical conductivity is at least 101.5 IACS and that the material is free from oxygen.

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