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Method for preparing processable BN complex phase ceramic capable of improving later-stage hardness

A composite ceramics, hardness technology, applied in the field of machinable BN composite ceramics preparation, to achieve the effect of simple and easy process, small particle size and good compatibility

Inactive Publication Date: 2009-10-28
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The present invention draws lessons from the characteristics of increased hardness of metal materials after heat treatment, and designs and prepares machinable ceramics with good processing performance and post-hardening treatment, which is very meaningful for the popularization and application of machinable ceramics, but no related materials have been found in the current published literature. Reports and related patents

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  • Method for preparing processable BN complex phase ceramic capable of improving later-stage hardness
  • Method for preparing processable BN complex phase ceramic capable of improving later-stage hardness
  • Method for preparing processable BN complex phase ceramic capable of improving later-stage hardness

Examples

Experimental program
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Effect test

Embodiment 1

[0025] a. Primary sintering: SiC is used as the ceramic matrix phase, and Al and h-BN are used as toughening and reactive phases. The mass ratio of each component is: SiC: 40%, h-BN: 20%, Al: 40%. The mixed powder was wet milled in a ball mill jar for 24 hours, the medium was absolute ethanol (concentration 99.7%), the balls were agate balls, dried at 70° C., and passed through a 200-mesh sieve. Put the h-BN / Al / SiC mixed powder into a Φ30mm graphite mold, plasma activation and rapid sintering, the first sintering temperature is 1000°C, the heating rate is 300°C / min, the pressure is 30MPa, the vacuum degree is 10Pa, and the heat preservation is 2min. The sintering process adopts Infrared temperature measurement, the sample is cooled with the furnace.

[0026] b. Secondary reaction heat treatment: The h-BN / Al / SiC multiphase ceramics after the primary sintering are processed into the required shape by conventional metal processing, and put into a vacuum furnace. 2 Under gas pro...

Embodiment 2

[0028] SiC is used as the ceramic matrix phase, and Ti and h-BN are used as toughening and reactive phases. The mass ratio of the components is: SiC: 60%, h-BN: 20%, Ti: 20%. Plasma activation fast primary sintering temperature is 900°C, heat preservation 3min; secondary reaction heat treatment temperature 1550°C: heat preservation 1.5h. All the other are with embodiment 1.

Embodiment 3

[0030] to Si 3 N 4 It is the ceramic matrix phase, and Al and h-BN are the toughening and reaction phases. The mass ratio of the components is: Si 3 N 4 : 80%, h-BN: 10%, Al: 10%. Plasma activation fast primary sintering temperature is 800°C, heat preservation 1min; secondary reaction heat treatment temperature 1500°C: heat preservation 1h. All the other are with embodiment 1.

[0031] The surfaces of the samples prepared in the above examples 1 and 2 were polished and subjected to Vickers hardness testing and microstructure research. Table 1 lists the Vickers hardness before and after heat treatment of Example 1: h-BN / Al / SiC Example 2: h-BN / Ti / SiC composite ceramics. It can be seen from Table 1 that after post-reaction heat treatment, the hardness of the machinable ceramics after sintering is greatly improved.

[0032] Table 1 Hardness changes of composite ceramics after primary sintering and secondary hardening treatment by plasma activation

[0033]

[0034] Comp...

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Abstract

The invention discloses a method for preparing a processable BN complex phase ceramic capable of improving the later-stage hardness, which comprises the following steps: adding active metals of aluminum or titanium and the like into the BN complex phase ceramic, and obtaining a compact sintered body through one-step sintering, wherein the hardness of the material is lower at that time, and the material can be processed into products with different shapes conveniently by adopting a common mechanical cutting method; and performing secondary heat treatment on the products so that the BN and the aluminum (titanium) generate a new hard ceramic phase in situ so as to greatly improve the hardness of the final products. The method has simple and easy technological processes and short sintering time. Besides, the method well solves the conflict between the processability and the hardness of the ceramic, and not only ensures the processability of the ceramic, but also keeps good characteristic of hardness of the ceramic.

Description

technical field [0001] The invention relates to a method for preparing machinable ceramics, in particular to a method for preparing machinable BN composite phase ceramics whose hardness is improved through post-hardening treatment. Background technique [0002] Machinable ceramics usually refer to ceramic materials whose material removal rate and surface roughness can meet certain engineering requirements under the process conditions of traditional cutting technology. Due to the use of traditional metal processing techniques, ceramic parts with complex shapes and precise dimensions can be obtained with relatively low processing costs, so they have very broad application prospects in many fields. Machinability index (M) is usually used to characterize the machinability of ceramic materials: it requires low hardness and high fracture toughness. [0003] At present, there are many types of machinable ceramics, such as mica glass ceramics, composite ceramics with weak interface...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/622C04B35/583C04B41/80
Inventor 金海云李颖贾祥亚乔冠军
Owner XI AN JIAOTONG UNIV
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