Oxidation Behavior of Copper at a Temperature below 300 °C and the Methodology for Passivation

Lee, Shao‐Kuan; Hsu, Pei‐Yi; Tuan, Wei‐Hsing

doi:10.1590/1980-5373-mr-2015-0139

Cited by 117 publications

(61 citation statements)

References 14 publications

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“…The oxygen content of each of the three starting powder conditions results from surface oxide films and oxides along the grain boundaries. The copper oxide will continue to grow when exposed to oxygen, as it does not passivate [42]. The surface oxide thickness as a function of time at room temperature was empirically derived by White and Germer [43].…”

Section: Discussionmentioning

confidence: 99%

Characteristics and Processing of Hydrogen-Treated Copper Powders for EB-PBF Additive Manufacturing

Ledford,

Rock,

Carriere

et al. 2019

Applied Sciences

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The fabrication of high purity copper using additive manufacturing has proven difficult because of oxidation of the powder feedstock. Here, we present work on the hydrogen heat treatment of copper powders for electron beam powder bed fusion (EB-PBF), in order to enable the fabrication of high purity copper components for applications such as accelerator components and vacuum electronic devices. Copper powder with varying initial oxygen contents were hydrogen heat-treated and characterized for their chemistry, morphology, and microstructure. Higher initial oxygen content powders were found to not only reduce surface oxides, but also reduce oxides along the grain boundaries and form trapped H2O vapor inside the particles. The trapped H2O vapor was verified by thermogravimetric analysis (TGA) and residual gas analysis (RGA) while melting. The mechanism of the H2O vapor escaping the particles was determined by in-situ SEM heated stage experiments, where the particles were observed to crack along the grain boundaries. To determine the effect of the EB-PBF processing on the H2O vapor, the thermal simulation and the validation of single melt track width wafers were conducted along with melting single layer discs for chemistry analysis. A high speed video of the EB-PBF melting was performed in order to determine the effect of the trapped H2O vapor on the melt pool. Finally, solid samples were fabricated from hydrogen-treated copper powder, where the final oxygen content measured ~50 wt. ppm, with a minimal residue hydrogen content, indicating the complete removal of trapped H2O vapor from the solid parts.

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Section: Discussionmentioning

confidence: 99%

Characteristics and Processing of Hydrogen-Treated Copper Powders for EB-PBF Additive Manufacturing

Ledford,

Rock,

Carriere

et al. 2019

Applied Sciences

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show abstract

“…On the contrary, for the sample bonded without the formic acid vapor, a number of unsintered fine Ag nanoparticles can be found in Figure 6d. Besides, the Cu surface without the formic acid vapor become much rougher than that with the formic acid vapor, which is probably caused by a serious oxidation of the Cu surface [37]. This indicates that the Cu surface oxides can be reduced by the formic acid vapor during the sintering bonding, which should contribute to improving the bond strength of the interface between the sintered Ag and the Cu substrate.…”

Section: Resultsmentioning

confidence: 99%

Robust Ag-Cu Sintering Bonding at 160 °C via Combining Ag2O Microparticle Paste and Pt-Catalyzed Formic Acid Vapor

et al. 2020

Metals

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With the assistance of Pt-catalyzed formic acid vapor, robust Ag-Cu bonding was realized at an ultra-low temperature of 160 °C under 3 MPa for 30 min via the sintering of Ag nanoparticles in situ generated from Ag2O microparticles. The Cu oxide layer at the interface after bonding can be eliminated, which improves the bond strength and electrical conductivity of the joint. A metallic bond contact between the sintered Ag and the Cu substrate is obtained without interfacial solid solution and intermetallic phases, and the shear strength is comparable to previous bonding at a higher temperature. The bonding mechanisms were figured out by comparing the bonding with and without the Pt-catalyzed formic acid vapor. This ultra-low temperature Ag-Cu bonding method may create more flexibilities in the structure design and material selection for power device integration.

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“…Copper only forms two thermodynamically stable oxides, namely CuO and Cu 2 O. From the Gibbs free energy point of view, the Cu 2 O phase likely formed first because the Cu 2 O phase (∆G 0 = −122 KJ/mol) formation has a lower Gibbs free energy than the CuO phase (∆G 0 = −99 KJ/mol) [15,16]. Moreover, Luo et al reported that only Cu 2 O is expected to form at very low oxygen partial pressures [17].…”

Section: Resultsmentioning

confidence: 99%

A Study on the Characteristics of Cu–Mn–Dy Alloy Resistive Thin Films

Lee

et al. 2019

Coatings

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Cu–Mn–Dy resistive thin films were prepared on glass and Al2O3 substrates, which wasachieved by co-sputtering the Cu–Mn alloy and dysprosium targets. The effects of the addition ofdysprosium on the electrical properties and microstructures of annealed Cu–Mn alloy films wereinvestigated. The composition, microstructural and phase evolution of Cu–Mn–Dy films werecharacterized using field emission scanning electron microscopy, transmission electronmicroscopy and X-ray diffraction. All Cu–Mn–Dy films showed an amorphous structure when theannealing temperature was set at 300 °C. After the annealing temperature was increased to 350 °C,the MnO and Cu phases had a significant presence in the Cu–Mn films. However, no MnO phaseswere observed in Cu–Mn–Dy films at 350 °C. Even Cu–Mn–Dy films annealed at 450 °C showedno MnO phases. This is because Dy addition can suppress MnO formation. Cu–Mn alloy filmswith 40% dysprosium addition that were annealed at 300 °C exhibited a higher resistivity of ∼2100 μΩ·cm with a temperature coefficient of resistance of –85 ppm/°C.

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Oxidation Behavior of Copper at a Temperature below 300 °C and the Methodology for Passivation

Cited by 117 publications

References 14 publications

Characteristics and Processing of Hydrogen-Treated Copper Powders for EB-PBF Additive Manufacturing

Characteristics and Processing of Hydrogen-Treated Copper Powders for EB-PBF Additive Manufacturing

Robust Ag-Cu Sintering Bonding at 160 °C via Combining Ag2O Microparticle Paste and Pt-Catalyzed Formic Acid Vapor

A Study on the Characteristics of Cu–Mn–Dy Alloy Resistive Thin Films

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