Ceramic core preparation method

Abstract

The invention discloses a ceramic core preparation method. The method includes the steps that 1, ceramic powder is dried at the temperature ranging from 105 DEG C to 140 DEG C, and the dried ceramic powder is added to a vacuum mixing and stirring machine to be stirred at the constant temperature ranging from 75 DEG C to 95 DEG C; 2, oleic acid with the mass accounting for 0.3-1% of ceramic powder is weighed and dissolved with absolute ethyl alcohol with the volume being 10-30 times that of the oleic acid, a oleic acid ethanol solution is sprayed into the ceramic powder, stirring is conducted, a gas outlet valve is opened, and full mixing and gas discharging are conducted; 3, plasticizer with the mass accounting for 14-17% of the ceramic powder is weighed and added to the ceramic powder after being molten, and full stirring is conducted; 4, the stirring speed is lowered, the gas outlet valve is closed, vacuumizing is conducted till the pressure reaches over 88 KPa, a vacuum pump is closed, the stirring speed is recovered, and stirring is conducted continuously till the surface of the ceramic slurry is smooth, level and free of visible bubbles and particles; 5, the ceramic slurry is transferred to a core pressing machine to be stirred over 8 hours, pressing of a green ceramic core is conducted, and shaping and calcination are conducted on the pressed green ceramic core.

Description

technical field [0001] The invention relates to a method for preparing a precision casting ceramic core. Background technique [0002] In the precision casting process, especially in the near-net-shape investment casting process, the ceramic core is an important transition part to form a hollow casting, which directly determines the structural shape and molding accuracy of the casting cavity. Precision casting has high quality requirements for ceramic cores, and more than 50% of unqualified castings in precision casting are caused by unqualified ceramic cores. The unqualified reasons for ceramic cores are mainly reflected in insufficient flexural strength, poor creep resistance and large shrinkage. [0003] In addition to the physical properties of the material itself, such as chemical composition, particle size distribution, etc., the factors that affect the flexural strength, creep resistance and shrinkage of the ceramic core are the most critical factors that are the pre...

AI Technical Summary

Problems solved by technology

[0005] The firing process is the most critical step affecting the quality of the ceramic core. Defects such as cracks, expansion, deformation, bubbles, peeling, etc., as well as physical properties such as flexural strength and firing shrinkage are closely related to the firing process, and the key to the firing process is It lies in the reasonable and precise control of roasting temperature and roasting time. This technical measure is a commercial secret in the industry and has no way of knowing.

On the other hand, the mechanical and thermodynamic properties of ceramic cores after firing often cannot meet the requirements of use. The common practice is to use silica sol or resin materials to perform high-temperature strengthening and low-temperature strengthening treatments. This method increases the complexity of the process. At the same time, it is not only not environmentally friendly, but also may cause adverse effects on the deformation of the core itself