The chemical composition of electrolytic copper, which has a purity of more than 99.97%, in the
microcosm directly affects the macroscopic physical properties. This paper will deeply reveal the
content characteristics of more than 20 elements in electrolytic copper, the interaction law and
its industrial impact, to provide scientific basis for material selection and quality control.
Core component composition system
1. Characteristics of main elements
Copper content: standard electrolytic copper Cu+Ag≥99.95%, high purity grade up to 99.999%.
Silver element: natural companion content of 0.002%-0.05%, with a conductive enhancement effect
Oxygen: 5-50ppm, Cu₂O exists at the grain boundary.
2. Trace element classification
Element type Typical content range Main existence form
Metallic impurities 10-500ppm Solid solution/intermetallic compounds
Non-metallic impurities 1-30ppm Oxides/Sulfides
Gaseous elements 0.1-5ppm Lattice gaps/micropores
Key Impurity Element Influence Mechanisms
1. Conductivity killer elements
Phosphorus (P): every 0.01% increase in conductivity decreased by 10% IACS
Iron (Fe): formation of FeCu₄ ordered phases, increasing electron scattering
Sulfur (S): with copper to generate Cu₂S, resistivity increased by 30 times
2. Mechanical properties of the regulatory elements
Arsenic (As): content of 0.001% tensile strength increase of 15%
Antimony (Sb): more than 0.005% leads to increased cold brittleness
Bismuth (Bi): 0.0001% of the hot working cracking
3. Corrosion resistance damage elements
Oxygen (O): content > 200ppm accelerate intergranular corrosion
Chlorine (Cl): 0.5ppm trigger stress corrosion cracking
Hydrogen (H): 1ppm lead to “hydrogen disease” defects
Comparison of international standard system
1. China GB/T 467-2010
Cu+Ag≥99.95%
Oxygen content ≤ 0.04
Sulfur content ≤ 0.003%
2. U.S. ASTM B115
Total metal impurity≤0.04%
Selenium+Tellurium≤0.0005%
Bismuth ≤0.0005%
3. Europe EN 1976
Arsenic+Antimony≤0.0015%
Iron+Nickel≤0.003%
Zinc ≤ 0.002%
Chemical control of the production process
1. Electrolytic refining control
Electrolyte composition: Cu²⁺ 40-50g / L, H₂SO₄ 180-220g / L
Temperature control: 55±2°C
Current density: 220-280A/m²
2. Impurity removal technology
Vacuum deoxidizing: residual oxygen ≤5ppm
Area melting: metal impurities ≤ 0.001%
Electrolytic purification: recovery rate of precious metal＞99
3. Gas element control
Melt covering agent: charcoal + borax
Inert gas refining: argon flow 0.5m³/t
Vacuum casting pressure: ≤ 10-³Pa
Detection and analysis technology evolution
1. Spectral analysis method
Inductively coupled plasma (ICP) detection limit 0.01ppm
Glow discharge mass spectrometry (GD-MS) accuracy up to ppb level
X-ray fluorescence (XRF) rapid detection error <0.005%.
2. Microscopic characterization techniques
Transmission electron microscopy (TEM) to observe grain boundary aggregation
Surface composition analysis by Auger Electron Spectroscopy (AES)
Secondary Ion Mass Spectrometry (SIMS) for three-dimensional elemental distribution
3. Physical property correlation
Resistivity method to assess total impurities: 0.0001% impurities cause 0.1% change in resistance
Hardness test for inverse alloying elements: 0.001% solid solution impurities for every 1 increase in HV
Thermal analysis to detect gas content: DSC curve heat absorption peaks to locate hydrogen and oxygen content.
Chemical Adaptation for Application Scenarios
1. Electronic grade copper foil
Sulfur + selenium <0.0005%
Surface profile Ra≤0.3μm
Grain size 10-25μm
2. Superconducting materials
Iron+Nickel＜0.0001%
Oxygen content ≤3ppm
Residual resistance ratio RRR＞300
3. Vacuum device
Total gas <2ppm
Volatiles ≤0.001%
Outgassing rate＜1×10-¹⁰Pa-m³/s
Future technological breakthrough direction
1. Limit purity control
6N grade (99.9999%) copper mass production technology
Single crystal copper dislocation density <10²/cm²
Surface contamination control <0.1 atomic layer
2. Precision element design
Trace rare earth modification (La,Ce add 0.0001-0.001%)
Nano-precipitation phase modification (5-10nm oxide dispersion)
Gradient composition structure (surface/core difference <0.005%)
3. Green preparation process
Recycling rate of electrolyte＞99%
Recovery rate of impurity elements＞95%
Energy consumption reduced to 2000kWh/t
Conclusion
The control of the chemical composition of copper electrolyte is a precise material science, and a
0.001% change in content may trigger a cascade reaction in performance. With nanoscale
breakthroughs in analytical technology and atomic-level regulation of preparation processes,
modern industry is unraveling the ultimate code for the microscopic composition of copper
materials. From semiconductor chips to fusion reactors, precise control of the chemical
composition of copper will become the core competitiveness for breaking through
technical bottlenecks and creating new material systems.