The invention relates to a preparation method and application of a tissue controllable ultra-high purity cobalt plate. The preparation method includes: Cold pressing molding, high vacuum sintered, high vacuum electron beam melting furnace, argon gas room stainless steel coating, including a forging deformation and total deformation coordination control three-dimensional isothermal forging sufficiently rapidly varying Angle intersection control rolling and heat treatment, turning processing, packaging and other steps, preparation of high purity cobalt a purity of 99.995% or more, the average grain size was 10 ~ 40 microns, The content of β‑Co of FCC structure in the plate is more than 50%, permeability is greater than 70%, permeability inhomogeneity is less than 1%. The preparation method designed by the invention can effectively control the grain size and grain size distribution of the finished product, and regulate the distribution of the finished product structure, which provides the raw material guarantee for its use as a high-quality target.
Metal cobalt is a typical ferromagnetic metal. When it is not magnetized, it is divided into many spontaneously magnetized magnetic domains (magnetization tends to saturate). Since the magnetic moment direction and magnitude of magnetic domains are different from each other, the net magnetic moment and magnetization vector of ferromagnetic materials are zero. When a certain external magnetic field is applied, the orientation of the previously randomly arranged magnetic domains will tend to be the same, and the ferromagnetic field will exhibit strong magnetism. Cobalt and cobalt-based alloys, as magnetic materials, are widely used in the preparation of optoelectronic components, magnetic recording heads, integrated circuits and other components, while high-purity cobalt (purity ≥5N) is often used in the preparation of magnetic sputtering target materials, as the raw materials for the preparation of semiconductor chip contact layer.
Cobalt is an allotrope, closely spaced hexagonal (HCP)α-Co at room temperature and face-centered cubic (FCC) β-Co at high temperature. Due to the structural differences between the HCP phase and the FCC phase, their different magnetic properties are determined. Compared with the face-centered cubic phase, the densely packed hexagon requires a larger magnetic field to reach saturation. Therefore, controlling the content of β-Co in the FCC structure at room temperature can improve the magnetron sputtering efficiency and film formation performance of the target.
With the rapid development of the new generation of information technology industry, the demand for high-purity metal materials and sputtering target materials is increasing. At the same time, the target physical and chemical properties, organizational structure, comprehensive performance, target stability in service process and the overall quality consistency of components have strict requirements. Magnetic permeability is an important index to evaluate the sputtering performance of the target. Using a magnetic target with high permeability can concentrate the magnetic field in the target as much as possible and make the glow process more stable. Therefore, improving the permeability of the vertical target surface can improve the film sputtering performance under vacuum.
