Method of preparing functional ceramic part of complex structure by powder injection molding

Abstract

The invention relates to a method of preparing a functional ceramic part of complex structure by powder injection molding. The method is characterized by comprising the following steps: S1, feed preparation: uniformly mixing functional ceramic powder with an adhesive to form a feed; S2, injection moulding: putting the feed prepared in the S1 in a powder injection moulding machine, and injecting the feed into a mold cavity under conditions of an injection pressure of 80-200 MPa and an injection temperature of 160-200 DEG C to form an injection blank; S3, degreasing: catalytically degreasing theinjection blank prepared in the S2 to form a catalytically degreased blank; S4, thermal degreasing: thermally degreasing the catalytically degreased blank prepared in the S3 to obtain a thermally degreased blank; and S5, sintering: putting the thermally degreased blank prepared in the S4 in a sintering furnace, and sintering the thermally degreased blank in an air atmosphere to obtain a sinteredblank. By setting a volume ratio range of the functional ceramic powder and the adhesive, the functional ceramic powder can be totally coated by the adhesive, so that the flawless injection blank is more easily obtained.

Description

technical field [0001] The invention relates to the field of preparation of a ceramic part with a complex structure and function, in particular to a method for preparing a ceramic part with a complex structure and function by powder injection molding. Background technique [0002] Because of their special dielectric properties, temperature characteristics, and extremely high corrosion resistance, strength, and hardness, ceramic materials are widely used in some parts that need to achieve special electromagnetic functions. With the development of industries such as electronic communication and automation, the structure of functional ceramic parts is becoming more and more complex. Functional ceramics refer to a new type of material with special functions, and its performance is extremely sensitive to the content of impurity elements and porosity. [0003] At present, the preparation method of functional ceramic parts is mainly prepared by powder compression molding. The disa...

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Problems solved by technology

[0003] At present, the preparation method of functional ceramic parts is mainly prepared by powder compression molding. The disadvantages are: 1) The green body obtained by compression molding has low dimensional accuracy and simple structure, and a large amount of machining is required to ensure the structure and quality of the product. Dimensional accuracy; 2) Affected by the characteristics of the compression molding method, the density / density of the product along the thickness direction is inconsistent, resulting in affected product performance, and the product has a large amount of deformation during the sintering process; 3) Compression molding has a greater impact on The fluidity requirement of the ceramic powder is higher, that is, the particle size of the powder needs to be coarser, usually D 50 ≥4μm, therefore, the sintering temperature of the product needs to be greatly increased

In summary: Functional ceramics prepared by pressing molding have poor control over product size, structural complexity, and product size consistency, which is not conducive to the batch preparation of complex structural functional ceramics

[0004] Although some patents have disclosed the method of preparing ceramics by powder injection molding, in summary, this type of patent mainly has the following disadvantages: 1) In the selection of binder types, most of them use wax-based binder systems , the disadvantage is that the degreasing time required is extremely long, requiring more than 72 hours

A plastic-based binder system is selected individually, but due to the superficial research on the catalytic degreasing process, a relatively accurate degreasing process cannot be given. Defects such as binder residues or sintering holes are formed in ceramic products, which affect product performance; 2) The volume ratio of binder to ceramic powder is not well studied, and the volume ratio range of binder to ceramic powder cannot be accurately given; 3 ) The particle size of the selected ceramic powder is usually very fine, D 50 ≤0.3μm, the cost of the powder increases greatly; 4) The wax-based binder has low molecular weight and low decomposition temperature, which leads to poor strength and poor shape retention of the injection blank, which is not conducive to the preparation of high-precision size products

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