CN111730732A

CN111730732A - Process for improving advanced ceramic sintering yield

Info

Publication number: CN111730732A
Application number: CN202010583536.6A
Authority: CN
Inventors: 姜家吉; 蓝晓斌
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-06-23
Filing date: 2020-06-23
Publication date: 2020-10-02

Abstract

A process for improving the sintering yield of advanced ceramics comprises the following steps: selecting a ceramic blank, pretreating the selected ceramic blank, and sintering the pretreated ceramic blank. The process adds a pretreatment procedure before sintering the ceramic blank body to form a ceramic (or semi-ceramic) frame structure on the blank body, and the structure has better functions of pressure resistance and tensile strength and can resist deformation generated in the sintering process of ceramic particles, thereby avoiding the poor effects of cracking, deformation, low size precision and the like of products in the sintering process.

Description

Process for improving advanced ceramic sintering yield

Technical Field

The invention relates to the field of advanced ceramic sintering processes, in particular to a process for improving the yield of advanced ceramic sintering.

Background

Advanced ceramics generally adopt high-purity and superfine raw materials, are made into ceramic materials with excellent performance through composition and structural design and by adopting accurate stoichiometry and a novel preparation technology, and are different from the traditional ceramics in the aspects of raw materials and processes. The biggest problem in the prior advanced ceramic processing is that the yield of the formed and sintered ceramic is low, mainly manifested by large deformation, warpage and the like of the product and difficult control. For example, the sintering yield of the ceramic mobile phone rear cover is even less than 30%. The reasons for rejection are mainly focused on dimensional errors and large deformations, so that only the machining allowance can be increased. This results in a high cost subsequent grinding process after sintering to remove a large amount of excess, which greatly increases the cost of the product.

The method for improving the sintering yield is researched by investing a large amount of manpower and material resources worldwide, and mainly changes the material component formula, the production process, the forming process, the drying process, the sintering process and the like in a centralized manner, so that the problem of low sintering yield still cannot be solved, and the method becomes a worldwide problem.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a process for improving the sintering yield of advanced ceramics, and provides a pretreatment process added before sintering of a formed blank by an innovative idea of limiting shrinkage and deformation in the sintering process, so that the blank can form a stable porcelainized (or semi-porcelainized) supporting frame (or supporting surface) before sintering, the liquid phase flow range in the sintering process is reduced, and the shrinkage and deformation rate are reduced. The consistency of the size and the shape of the finished product is greatly improved, and the problem of low yield in the sintering process is fundamentally solved, so that the working hours of subsequent machining and grinding are greatly reduced or even not needed.

In order to achieve the aim of the invention, the invention adopts the specific scheme that:

a process for improving the sintering yield of advanced ceramics comprises the following steps:

(1) selecting a ceramic blank;

(2) pretreating the selected ceramic blank;

(3) and sintering the pretreated ceramic blank.

Further, the pretreatment is to adopt laser instant heating to sinter a semi-porcelainized frame or surface structure with strength on the surface of the ceramic blank.

Further, the pretreatment method can also adopt chemical vitrification, microwave heating vitrification, plasma heating vitrification or laser heating vitrification to sinter the surface of the ceramic blank.

Further, the frame structure formed on the surface of the ceramic blank after the pretreatment may have various forms depending on the product shape structure.

The invention has the beneficial effects that:

the process is characterized in that a frame structure which can enable a blank body to have better pressure resistance and tensile resistance in the sintering process is thermally treated in the ceramic blank body, and the adhesion and agglomeration mechanisms of particles acting on ceramic particles comprise Van der Waals force, electrostatic force, magnetic force, liquid film adhesion, adhesion force, surface acting force and the like which are factors influencing the agglomeration force of ceramic powder particles. The compressive resistance and tensile resistance provided by the frame system can provide better cohesion for the ceramic powder particles, thereby better avoiding the occurrence of undesirable effects such as cracking, deformation and the like in the sintering process of the product. The results after the process experiment are compared: the size error is reduced from 0.2mm to 0.01mm, the sintering yield is improved from 30% to nearly 100%, the general assembly requirement is basically met, and the subsequent processing time and cost are greatly reduced (approximately 80-90% of the processing cost is saved).

Drawings

Fig. 1 is a flow chart of a manufacturing process of a conventional microcrystalline zirconium ceramic mobile phone case.

Fig. 2 is a flow chart of a preparation process of the microcrystalline zirconium ceramic mobile phone shell after the process is used.

Detailed Description

The present invention is further described below by way of specific examples, but the present invention is not limited to only the following examples. Variations, combinations, or substitutions of the invention, which are within the scope of the invention or the spirit, scope of the invention, will be apparent to those of skill in the art and are within the scope of the invention.

The first embodiment is as follows: the microcrystalline zirconium ceramic mobile phone shell is taken as an example for detailed description

The preparation process of the existing microcrystalline zirconium ceramic mobile phone shell can be roughly divided into the following steps: blank shaping, structure processing, product surface treatment and LOGO processing.

Wherein the idiosome shaping is including dry pressing and sintering, and structure processing includes laser cutting, appearance corase grind and CNC processing, and product surface treatment includes SM, ball-milling and polishing, and LOGO handles including electroplating or laser processing. The specific process is shown in Table 1.

TABLE 1

The preparation process of the microcrystalline zirconium ceramic mobile phone shell using the process can be roughly divided into the following steps: blank shaping, structure processing, product surface treatment and LOGO processing.

Wherein the embryo shaping includes dry pressing, laser heat treatment frame system and sintering, and structure processing includes laser drilling, and product surface treatment includes SM, ball-milling and polishing, and LOGO handles including electroplating or laser processing. The specific process is shown in Table 2.

TABLE 2

In summary, the existing processing technology is complex, especially the sintering yield is very low, the processing allowance is large, the cost of the ceramic rear cover of the mobile phone is far higher than that of the glass rear cover, which is the main reason that the ceramic rear cover of the mobile phone cannot be comprehensively popularized later, and the size between the blank sintered under the support of the frame system and the finished product is very close, so that the high-cost working procedures of a plurality of structure processing can be saved while the sintering yield is improved. Thereby realizing the comprehensive popularization of the ceramic rear cover.

Example two:

processing a batch of dry-pressed aluminum oxide ceramic blanks, then carrying out various frame systems designed by laser heat treatment on partial blanks, then putting untreated blanks and treated blanks into the same sintering furnace to be sintered under the same condition, and finally carrying out dimension measurement through a quadratic element. Laser power: 20W, and the adjustable pulse width is 1-200 ns. Processing time: single-sided vertical bars for 30 seconds, single-sided horizontal bars for 60 seconds, single-sided vertical bar dashed lines for 25 seconds, single-sided horizontal bar dashed lines for 25 seconds, and single-second horizontal and vertical bar dashed lines for 50 seconds. Processing temperature: the solidification and crystallization temperature of the alumina ceramic is about 1600 ℃. The measurement data are shown in Table 3.

TABLE 3

The theoretical length of the product is 67mm, and the width is 51 mm. The laser-cured line width was 1 mm.

In summary, from the measured data, it can be seen that the ceramic sample size of the frame system for laser thermal treatment is more stable, and the size difference between the samples is smaller, so as to achieve the effect of improving the yield. It can be seen from the data table that the vertical bar frame can control the length dimension of the sample, and the horizontal bar frame can control the width dimension of the sample.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the present invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A process for improving the sintering yield of advanced ceramics is characterized by comprising the following steps:

(1) selecting a ceramic blank;

(2) pretreating the selected ceramic blank;

(3) and sintering the pretreated ceramic blank.

2. The process according to claim 1, wherein the step of improving the sintering yield of advanced ceramics comprises the steps of: the pretreatment is to adopt laser instant heating to sinter a semi-porcelainized frame or surface structure with strength on the surface of the ceramic blank.

3. The process according to claim 2, wherein the step of improving the sintering yield of advanced ceramics comprises: the pretreatment method can also adopt chemical vitrification, microwave heating vitrification, plasma heating vitrification or laser heating vitrification to sinter the surface of the ceramic blank.

4. The process according to claim 2, wherein the step of improving the sintering yield of advanced ceramics comprises: the frame structure formed on the surface of the ceramic blank after the pretreatment can have various forms according to the appearance structure of the product.