High-energy ball milling preparation method of barium titanate-based semiconductor ceramics

Abstract

The invention discloses a method for preparing a barium titanate-based PTC (Positive Temperature Coefficient) semiconductor ceramic fine crystalline structure, which comprises the following steps: using barium carbonate, titanium dioxide, yttrium oxide, manganese nitrate, strontium carbonate or / and calcium carbonate as raw materials, filtering slurry by using ZrO2 spherules with the diameter of 1 to 2mm and a gap with the thickness of 1mum, wherein the rotating speed is 1400 to 2400rpm and the ball milling time is 1 to 3 hours, and finally obtaining barium titanate-based PTC powder with the grain diameter of 20 to 50nm; then adding a dispersant, an adhesive and a plasticizer for mixing and ball milling for 3 to 5 hours, then standing for 5 to 12 hours, removing bubbles, carrying out physical aggregation, and finally carrying out sieving treatment to obtain casting slurry; and finally carrying out casting operation for the casting slurry to prepare a barium titanate ceramic green body. The obtained chip fine crystal PTC is characterized in that the magnetic crystal grain size is below 2 microns, the room temperature resistivity is not more than 120 Omega.cm, the lift-drag ratio is not less than 4*103, and the Curie temperature is 80 to 120 DEG C.

Description

technical field [0001] The invention relates to the manufacture of a chip-type semiconductor ceramic electronic component with a fine-grained structure, in particular to barium titanate (BaTiO 3 ) semiconducting ceramic materials, and electronic components such as thermistors using such ceramic materials. Background technique [0002] BaTiO with a positive temperature coefficient 3 Semiconductor-based ceramics (hereinafter referred to as PTC), as a thermistor component, have been widely used in various equipment and instruments, such as the degaussing of ray tubes in color TV sets, and the overcurrent protection of circuits. [0003] With the rapid development of SMT technology, it has greatly promoted the miniaturization, miniaturization, integration and chip of electronic equipment and electronic components, and the preparation of chip PTCR has become a research hotspot at home and abroad. In order to make the miniaturized chip PTCR element maintain good PTC effect, high...

AI Technical Summary

Problems solved by technology

[0004] Judging from the technologies that have been published so far, the US6911102B2 patent uses BaTiO 3 Doped with 0.2% mol or less of nickel and 0.2% to 20% mol of boron as the internal electrode, fired in a reducing atmosphere and re-oxidized, and finally obtained a resistance value of 0.17-3.5Ω, a lift-to-drag ratio The order of magnitude is 2.8-3.6, and the withstand voltage is above 10V, but the room temperature resistivity and grain size are not accurately given

The patent US6472339 prepares barium titanate powder by doping barium titanate with lanthanum and using hydrolysis method. Finally, through sintering process, the grain size is 0.9μm, the room temperature resistivity is 50Ω.cm, and the withstand voltage It is 900V / mm, but its PTC effect has not been reported in detail

So far, there is no report on the realization of low resistivity, fine-grained structure and high lift-to-drag ratio at the same time.