Phosphorus element, as a typical harmful impurity in tungsten-nickel-iron alloy, is typically controlled to below 0.01%. Even in trace amounts, it influences the alloy’s mechanical properties, corrosion resistance, and processing stability through grain boundary segregation and compound precipitation.

Sulfur element predominantly exerts harmful effects on tungsten-nickel-iron alloy performance: its impact is minimal at low levels, but excessive sulfur content leads to the formation of low-melting-point sulfides and grain boundary weakening, resulting in a sharp decline in impact toughness, deterioration of strength and plasticity, reduced corrosion resistance, and hindered processability.

Sulfur element, as a typical impurity element in tungsten-nickel-iron alloy (typically introduced via raw materials or mixed in during smelting), exists in low concentrations but significantly affects the alloy’s mechanical properties, corrosion resistance, and processability. This influence is primarily realized through sulfur’s forms of existence (sulfide precipitation, grain boundary segregation) and its interaction with the matrix, exhibiting systematic variations based on sulfur content, precipitate type, and service environment.

The influence of carbon element on the corrosion resistance of tungsten-nickel-iron alloy is primarily mediated through its forms of existence (carbides, solid solution, or interfacial segregation) and its regulation of microstructure. This manifests as effects on electrochemical corrosion behavior, passivation film integrity, and corrosion morphology, with the impact varying depending on carbon content, corrosive environment, and alloy microstructure.

Although carbon is typically present in trace amounts in tungsten-nickel-iron alloy, its influence on alloy performance is significant. Carbon exhibits a "double-edged sword" effect: small amounts enhance strength and hardness through solid-solution strengthening and carbide dispersion strengthening, while excessive carbon reduces toughness and fatigue resistance due to brittle phase precipitation and interface weakening.

Oxygen is a critical factor in regulating the performance of tungsten-nickel-iron alloy. Through mechanisms such as oxide inclusion formation, solid-solution strengthening, and grain boundary segregation, it impacts the alloy’s mechanical properties, thermal stability, and processability. Therefore, in practical applications, oxygen content must be controlled within reasonable limits through raw material purification, process optimization, and deoxidation techniques to fully leverage the alloy’s advantages in high density, high strength, and excellent corrosion resistance.

The impurity elements in tungsten-nickel-iron alloy (W-Ni-Fe) originate from complex sources, primarily involving raw materials, production processes, and environmental media.

In addition to the primary elements tungsten, nickel, and iron, tungsten-nickel-iron alloy contains trace impurity elements such as hydrogen, oxygen, carbon, sulfur, and phosphorus. These impurities can compromise grain boundary integrity, form brittle phases, and reduce the alloy’s conductivity, high-temperature strength, and radiation resistance. Control is achieved through raw material purification and process optimization, such as vacuum sintering. The following outlines the impact of key impurity elements on alloy performance.

Hydrogen’s influence on tungsten-nickel-iron alloy performance—through hydrogen embrittlement, conductivity degradation, and hydrogen retention—can reduce material reliability. However, controlling hydrogen content and enhancing performance can be achieved through alloy design and surface engineering.

Tungsten-nickel-iron alloy (W-Ni-Fe alloy) is a high-density alloy with tungsten as its matrix, allowing for a balance of density, strength, toughness, and cost through the adjustment of the nickel-iron ratio or the addition of trace elements. It is widely used in aerospace, defense, medical devices, and other fields. The alloy’s material composition includes tungsten, nickel, iron, carbon, and other elements.