Tungsten

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Impact of Phosphorus Element on Tungsten-Nickel-Iron Alloy Performance 10

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. I. Forms of Phosphorus in Tungsten-Nickel-Iron Alloy Comprising tungsten particles and a nickel-iron binder phase, tungsten-nickel-iron alloy contains phosphorus in three primary forms: Solid Solution: A small amount of phosphorus can dissolve into the nickel-iron binder phase. Compound State: Excess phosphorus forms…

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Methods to Reduce Sulfur Content in Tungsten-Nickel-Iron Alloy 8

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. Methods to Reduce Sulfur Content in Tungsten-Nickel-Iron Alloy The core strategy for lowering sulfur content in tungsten-nickel-iron alloy lies in cutting off sulfur introduction pathways and enhancing sulfur removal…

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Impact of Sulfur Element on Tungsten-Nickel-Iron Alloy Performance 10

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. I. Forms and Distribution Characteristics of Sulfur in Tungsten-Nickel-Iron Alloy Sulfur’s atomic…

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Impact of Carbon Element on the Corrosion Resistance of Tungsten-Nickel-Iron Alloy 17

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. I. Mechanisms of Carbon’s Influence on Corrosion Resistance Micro-Galvanic Corrosion Effect of Carbides When carbon exceeds its solubility limit in tungsten-nickel-iron alloy,…

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Impact of Carbon Element on Tungsten-Nickel-Iron Alloy Performance 4

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. Carbon element primarily exists as an impurity in tungsten-nickel-iron alloy, originating from residual carbon in raw powders (e.g., trace carbon in tungsten powder), contamination during preparation, or…

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How to Remove Molybdenum Impurities from Sodium Tungstate? 7

The removal of molybdenum (Mo) impurities from sodium tungstate (Na?WO?) is a critical step in the purification process of tungsten chemicals, especially for producing high-purity tungsten products or intermediates such as APT (Ammonium Paratungstate) and AMT (Ammonium Metatungstate). Since both molybdenum and tungsten belong to Group VI B of the periodic table and exhibit similar chemical properties, their separation is particularly challenging. Below are commonly used methods and the principles behind them: I. Forms of Molybdenum Impurities In alkaline conditions,…

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Impact of Oxygen on Tungsten-Nickel-Iron Alloy Performance 16

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. I. Forms and Mechanisms of Oxygen Presence Oxygen in…

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Sources of Impurity Elements in Tungsten-Nickel-Iron Alloy 17

The impurity elements in tungsten-nickel-iron alloy (W-Ni-Fe) originate from complex sources, primarily involving raw materials, production processes, and environmental media. I. Impurities Introduced by Raw Materials Impurities in Tungsten Raw Materials: As the matrix material (90%–98%), tungsten powder often contains oxygen (O), carbon (C), nitrogen (N), silicon (Si), aluminum (Al), and calcium (Ca). Elements like arsenic (As), tin (Sn), and antimony (Sb), naturally associated with primary tungsten ores, may persist in the alloy through smelting residues. Impurities in Nickel-Iron Binder…

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Impurity Elements in Tungsten-Nickel-Iron Alloy 16

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 (H): With extremely low solubility in tungsten, it tends…

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Impact of Hydrogen on Tungsten-Nickel-Iron Alloy Performance 14

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. I. Hydrogen Embrittlement Effect: Plasticity Loss and Fracture Risk Hydrogen’s solubility in tungsten-nickel-iron alloy is significantly lower than in nickel or iron, leading to its enrichment at grain boundaries, dislocations, and second-phase interfaces. This enrichment triggers two typical hydrogen embrittlement mechanisms: Stress-Induced Hydrogen Precipitation: Under tensile or fatigue…

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