OFHC copper

Appleton and Waddington [40] present experimental evidence that pulse duration also affects residual strength in OFHC copper. Samples shock loaded to 5 GPa for 1.2 ps pulse duration exhibit poorly developed dislocation cell structure with easily resolvable individual dislocations. When the pulse duration is increased to 2.2 ps (still at 5 GPa peak stress) recovered samples show an increase in Vickers hardness [41] and postshock electron micrographs show a well-developed cell structure more like samples shock loaded to 10 GPa (1.2 ps). In the following paragraphs we give several additional examples of how pulse duration affects material hardness. 

Christman, D.R., Isbell, W.M., and Babcock, S.G., Measurements of Dynamic Properties of Materials, Vol. V, OFHC Copper, US Defense Atomic Support Agency Report No. DASA 2501-5, Washington, DC, 104 pp., July 1971. 

Resistors of 100-200 kO, realized with a heavily doped meander implanted on a 1 mm3 silicon chip, are attached to each absorber in order to calibrate and stabilize the gain of the bolometer over long running periods. The towers will be mechanically connected to an OFHC copper top plate, elastically suspended from the DR mixing chamber. 

To fulfil the background requirements typical of rare event physics, particular care was dedicated to the selection and treatment of the materials used for the construction of CUORICINO the crystals where grown with low contamination materials in China and sent by ship to Italy where they have been optically polished with specially selected low-contamination powders. The mechanical structure of the array was made exclusively in OFHC copper and PTFE both these materials have an extremely low radioactive content. All the copper and PTFE parts of the mounting structure underwent a chemical treatment to remove any possible surface contamination. Finally, the array was assembled in an underground clean room in a N2 atmosphere to avoid Radon contamination. 

Density Mg/m3) Confinement (mm OFHC copper) p = 8.920Mg/m3 Detonation Velocity Corrected to p= 1.615Mg/m3... 

The N(ls) high-resolution spectra obtained from polished OFHC copper which had been coated with y-APS from a 1% aqueous solution at pH 10.4 are shown in Fig. 11. Only one component near 399.8 eV was observed in the N(ls) spectra regardless of the take-off angle. The strong peak near 409.0 eV in Fig. 11 was related to a copper LM V Auger line. 

Figure 11. N(1j) high resolution spectra of polished OFHC copper coated with y-APS from a 1% aqueous solution at pH 10.4. The take-off angles were (A)—15 and (B)—75°.

Figure 12. (A) Cu(2pw2 photoelectron and (B)—LVV Auger spectra obtained with polished OFHC copper before coating with y-APS.

Figure 18-1. Schematic diagram of the X-band EPR apparatus for the 6K X-irradiation and EPR measurements. The crystal is cemented to an OFHC copper pedestal that is part of an Air Products Heli-Tran system. The diagram shows the crystal in the irradiation position. After irradiation the crystal is lowered in a cylindrical EPR cavity. The cavity is cooled to 77 K to serve as a heat shield. (Reprinted with permission from ref. [12], J. Chem. Phys. (1981) American Physical Society)...

Yttrium or misch metal for improving the oxidation resistance of OFHC copper and elimination of hot tearing in leaded brasses... 

K data—results of measurement are an average for two samples of as-received and stress-relieved OFHC copper 300 K data—value for specific heat obtained from Ref. [ ]. 

Nb CORES IN OFHC COPPER 800 UNITS) TANTALUM CLAD COPPER (g) TIN ALLOY... 

The curves in Fig. 1 show the thermal zeroshifts for four gauges that were mounted on OFHC copper. The data for the other four samples were similar, but were shifted up or down slightly, according to the expansion coefficient of the substrate material. 

Fig. 1. Thermal zeroshift (apparent strain) for WK-XX-125 AD-350 strain gauges on OFHC copper sample for self-temperature compensation XX = 06, 09, 13, and 15.

Figure 2 shows the apparent-strain curve expanded near 4.2 K for a WK-15-125AD-350 strain gauge with a 15-ppm/°F compensation bonded to the 2024-T3 aluminum beam used for gauge factor measurements. For the 1-degree interval between 4.2 and 5.2 K, the apparent strain is approximately -150 /im/m. For this same gauge bonded to OFHC copper, the corresponding apparent strain is about -210 /xm/m. 

Espinosa T, Sanes J, Jimenez AE, Bermudez MD (2013) Surface interactions, corrosion processes and lubricating performance of protic and aprotic ionic liquids with OFHC copper. Appl Surf Sci 273 578-597. doi 10.1016/j.apsusc.2013.02.083... 

The detector holder, clamps and cooling rod in a standard detector would normally be of OFHC copper, but selected copper of much higher purity would be used for a low background system. A berylhum window will be of specially selected material stainless-steel screws replaced by brass or low-cobalt stainless-steel and rubber O-rings might be replaced by indium metal. Even such careful selection may have unexpected consequences indium has a high capture cross-section for thermal neutrons. 

The primordial (half-hfe 4.41 x 10 " year, a pure P emitter) was removed by remaking the soldered connection with the ancient lead. All OFHC copper components in the cryostat were re-fabricated by electroforming from highest purity copper sulfate solution, and thus the penultimate spectrum obtained, with count rates of 2 x 10 to 5 x 10 counts keV min . ... 

Certified OFHC Copper 101 OFHC Copper 102 Boron Deoxidized Copper 109 Silver Bearing Copper 113 Silver Bearing Copper 114 Silver Bearing Copper 116 DLP Copper 120 Phosphorized Copper 122 Phosphorized Arsenical... 

Figure 44 Package constructions used to evaluate the thermal transfer properties of the die attachment materials and substrates. TO-3 steel package is composed of steel case la, OFHC copper 2a, nickel film 3, soft solder 4a, and integrated circuit 5. TO-3 aluminium package is formed of aluminium header lb plated with nickel 3 on the top of which a silver-filled epoxy adhesive 4b is employed to bond the semiconductor device 5. The 24-lead CERDIP package is based on nickel-plated alumina substrate Ic with soft solder bonded silicon chips. In 40-lead plastic package, integrated circuits 5 are bonded to leadframes 2b by using silver-filled epoxy adhesive 4b and then encapsulated in moulding...

Electrical and other properties of copper render it the most widely used metallic conductor. Oxygen-free high-conductivity (OFHC) copper, having extremely low oxygen and other impurity contents, is produced for many electrical applications. Aluminum, having a conductivity only about one-half that of copper, is also frequently used as an electrical conductor. Silver has a higher conductivity than either copper or aluminum however, its use is restricted on the basis of cost. 

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