Nano-nickel powder of core-shell structure

Abstract

The invention discloses a nano-nickel powder of a core-shell structure. The nano-nickel powder comprises a spherical nickel bead and a protecting layer, wherein the outer surface of the spherical nickel bead is coated with the protecting layer, and the protecting layer has the passivation function and the agglomeration-preventing function. The spherical nickel bead is of a crystal structure; the diameter of the spherical nickel bead is 10-600 nanometers; and the thickness of the protecting layer which is a nickel-sulphur-oxygen protecting layer is 0.5-6 nanometers. The nickel-sulphur-oxygen protecting layer comprises 10-25% of nickel sulfide, 50-75% of nickel oxide, 3-10% of nickel hydroxide, basic nickel carbonate, 1-3% of carbon dioxide and 0.1-0.5% of water. The degree of sphericity of the nickel powder is high; the crystal structure is complete; the dispersibility is high; the sintering temperature is high; and the shrinkage rate is low.

Description

technical field [0001] The invention relates to the technical field of new material powders, in particular to a nano-nickel powder with a core-shell structure. Background technique [0002] Nano-nickel powder has a series of unique physical and chemical properties such as high surface energy, large specific surface area, good electrical conductivity, thermal conductivity, and strong oxidation resistance. It shows excellent performance in magnetism, thermal resistance, internal pressure, light absorption, and chemical activity. Many specific functions, so it has broad application prospects in the fields of electronic paste, conductive paste, high-efficiency catalysts, additives and light-absorbing materials. Chip multilayer ceramic capacitors (mlcc) --- referred to as chip multilayer ceramic capacitors, are laminated by ceramic dielectric diaphragms with printed electrodes (internal electrodes) in a dislocation manner, and are formed into ceramics after one-time high-temperat...

AI Technical Summary

Problems solved by technology

[0003] In the production process of ceramic capacitors, paste is printed on the dielectric printed circuit board and heat treatment is used to evaporate and remove organic components after lamination and pressure bonding. The heat treatment is usually carried out at 250°C-400°C in the atmosphere. When performing oxidation treatment , the metal nickel powder is oxidized and expands, and at the same time, the volume shrinks due to sintering, which leads to deformation of the dielectric layer and electrode layer, and cracking or peeling in severe cases

[0004] Not only that, but with the miniaturization and increase in capacity of ceramic capacitors, the internal electrodes of current multilayer ceramic capacitors are also thinner and have lower resistance. Usually, when multilayer capacitors are manufactured and fired, electrode layers and dielectric Peeling between the layers or cracks in the electrode layer, and if there are coarse particles in the nickel powder, the surface of the electrode layer will have unevenness and increase, resulting in a short circuit between electrode layers or a drop in withstand voltage

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