Currently, the most important and effective method for preparing high-purity tantalum ingots is vacuum electron beam melting. The principle involves bombarding the tantalum raw material with a high-energy-density electron beam under high vacuum, causing it to melt and solidify by dripping it into a water-cooled copper crucible. The purification mechanism in this process is crucial: deep degassing. Gaseous impurities in metallic tantalum (such as O, N, and H) will volatilize and escape in large quantities under vacuum and high temperature, thus being effectively removed.
Metallic impurity volatilization. During the melting process, lower-melting-point metallic impurities (such as certain alkali metals) also volatilize and separate due to the high temperature. Densification. The tantalum ingot after densification has a dense structure, with significantly reduced internal defects (such as shrinkage cavities and cracks), and a density typically exceeding 16.5 g/cm³ (the theoretical density of tantalum is 16.65 g/cm³). Through one or more electron beam melting processes (e.g., two processes in different orientations), ultra-high purity tantalum ingots with a purity ≥99.995% can be obtained. The total amount of key impurities W, Mo, and Nb can be controlled below 20 ppm, and gaseous impurities C≤10 ppm, O≤15 ppm, N≤10 ppm, and H≤2 ppm. The company has achieved breakthroughs and industrial integration in the entire process of producing high-purity tantalum powder, high-purity tantalum ingots, and 12-inch tantalum target blanks, marking the product's ability to be supplied in large quantities domestically. Purity reaches international levels: the purity of its ultra-high purity tantalum target blank has reached 5N9 (99.9999%), breaking through foreign technological barriers and product monopolies. Main application areas: High-purity tantalum ingots are not the final product; they are usually further processed into key industrial components, mainly used in semiconductor chip sputtering targets and blanks. They are also used as barrier layer materials in copper interconnect processes to prevent copper diffusion into the silicon substrate, and are core consumables in the manufacturing of AI chips and 5G chips.
High-purity tantalum can be used as a diffusion barrier layer or alloy additive in the preparation of low-temperature superconducting wires such as NbTi/Cu, preventing the reaction between copper and the superconducting core wire and ensuring superconducting performance.
In high-temperature alloys, tantalum significantly improves the high-temperature resistance and corrosion resistance of materials, making it suitable for extreme environments such as aerospace engines. In other fields, it is used for chemical corrosion protection and in tantalum capacitors, where its excellent corrosion resistance and electrochemical properties are utilized.
High-purity tantalum ingots are a core high-end material prepared using vacuum electron beam melting technology. Breakthroughs in their domestic production are of significant strategic importance for ensuring the security of my country's semiconductor industry chain and supporting the development of cutting-edge fields such as superconductivity and high-temperature alloys. High-purity tantalum ingots are mainly processed into sputtering targets for semiconductor manufacturing. (For further information on domestic substitution of 12-inch tantalum target blanks, see below.)
In aerospace and defense, tantalum is used as an additive in the manufacture of high-temperature alloys or directly as a tantalum alloy structural material. It significantly improves the high-temperature resistance (operating temperatures can reach above 1800℃), corrosion resistance, and thermal shock resistance of materials, making it suitable for extreme environment components such as engine hot sections, rocket nozzles, and missile nose cones. As a key additive or barrier layer material, it is used in the preparation of low-temperature superconducting wires such as NbTi/Cu to ensure that the performance of the superconducting core wire is not affected by diffusion in the copper matrix, which is fundamental to the realization of large scientific devices such as MRI and particle accelerators. Demand is stable, but the technical threshold is high. It is also used in the manufacture of tantalum capacitors, chemical corrosion-resistant equipment, and hard alloy additives. Utilizing its excellent corrosion resistance, high dielectric constant, and high melting point, it is widely used in consumer electronics, chemical industry, and military fields. These are mature application areas with a stable market. Tantalum and niobium not only dominate the domestic market, but also have an international market share of approximately 40%, demonstrating the strong competitiveness of high-purity tantalum ingots manufactured in China globally.
