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Preparation method of h-BN/NbB2 machinable ceramics

A technology of h-bn and ceramics, which is applied in the field of h-BN/NbB2 machinable ceramics, can solve the problems of low bending strength and achieve the effects of high strength, high overall reliability and excellent oxidation resistance

Inactive Publication Date: 2014-06-18
SHANDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the machinable ceramic materials prepared by the usual hybrid and chemical h-BN coating technology have low flexural strength

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] The first step: uniformly mix boric acid: urea in a weight ratio of 2:1, add 30% ethanol, heat treatment at 50°C in a closed container for 24 hours, and then stir for 30 minutes to make an esterification solution;

[0013] The second step: NbB with a particle size of 0.1 μm 2 Add 70% of the ceramic powder to a 30% esterification solution to make a ceramic slurry, and then use a spray granulator to make the above ceramic slurry into a coated NbB with a diameter of 0.5mm 2 Powder, the above-mentioned coated NbB 2 The powder was nitrided in a nitrogen atmosphere at a temperature of 600°C for 30 minutes to obtain h-BN-coated NbB2 ceramic powder, and h-BN-coated NbB 2 The ceramic powder is isostatically pressed under a pressure of 100MPa. into a ? 2 Machinable ceramics.

[0014] The purity of the batching raw materials used in the experiment is industrial pure, and the obtained h-BN / NbB 2 The bending strength of machinable ceramics is 479MPa.

Embodiment 2

[0016] The first step: uniformly mix boric acid: urea in a weight ratio of 2:1, add 45% ethanol, heat in a closed container at 70°C for 16 hours, and then stir for 20 minutes to make an esterification solution;

[0017] The second step: NbB with a particle size of 1 μm 2 Add 55% of the ceramic powder to 45% esterification solution to make a ceramic slurry, and then use a spray granulator to make the above ceramic slurry into a coated NbB with a diameter of 0.2mm 2 Powder, the above-mentioned coated NbB 2 The powder was nitrided in a nitrogen atmosphere at a temperature of 800°C for 45 minutes to obtain h-BN-coated NbB 2 Ceramic powder, h-BN coated NbB 2 The ceramic powder is isostatically pressed under a pressure of 150MPa. into a ?60×15mm sheet green body, and then hot-pressed at 1800℃×105 minutes under a nitrogen atmosphere at 50MPa. Fired into h-BN / NbB 2 Machinable ceramics.

[0018] The purity of the batching raw materials used in the experiment is industrial pure, an...

Embodiment 3

[0020] The first step: uniformly mix boric acid: urea in a weight ratio of 2:1, add 60% ethanol, heat treatment at 90°C in a closed container for 10 hours, and then stir for 10 minutes to make an esterification solution;

[0021] The second step: NbB with a particle size of 2 μm 2 Add 40% of ceramic powder to 60% esterification solution to make ceramic slurry, and then use the spray granulator to make the above ceramic slurry into coated NbB with a diameter of 0.01mm 2 Powder, the above-mentioned coated NbB 2 The powder was nitrided in a nitrogen atmosphere at a temperature of 1000°C for 60 minutes to obtain h-BN-coated NbB 2 Ceramic powder, h-BN coated NbB 2 The ceramic powder is isostatically pressed under a pressure of 200MPa. into a ?60×20mm sheet green body, and then hot-pressed at 1850℃×180 minutes under a nitrogen atmosphere at 100MPa. Fired into h-BN / NbB 2 Machinable ceramics.

[0022] The purity of the batching raw materials used in the experiment is industrial p...

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Abstract

The invention relates to a preparation method of h-BN / NbB2 machinable ceramics, which is characterized by performing cold isostatic compaction on an h-BN coated NbB2 ceramic powder body, then performing hot compaction, and firing to obtain the h-BN / NbB2 machinable ceramics. The preparation method comprises the following steps: proportionally mixing boric acid and urea with ethanol in a closed container, thus preparing an esterification solution; then, adding an NbB2 ceramic powder body into the esterification solution, thus preparing ceramic slurry; preparing the ceramic slurry into a coated NbB2 powder body through a spray granulator; nitridizing the coated NbB2 powder body to obtain the h-BN coated NbB2 ceramic powder body; performing isostatic compaction on the h-BN coated NbB2 ceramic powder body to obtain a lamellar green body; and performing hot compaction under nitrogen atmosphere, and firing to obtain the h-BN / NbB2 machinable ceramics. The machinable ceramics prepared by the invention are uniform in h-BN phase distribution, controllable in content and fine in machinability, mechanical properties and thermal properties.

Description

technical field [0001] The present invention relates to a kind of h-BN / NbB 2 A machinable ceramic belongs to the technical field of ceramic preparation. Background technique [0002] Ceramic materials have many excellent properties. However, due to the high hardness of ceramic materials, when preparing precision-sized ceramic parts, they can only be ground by diamond abrasive grinding wheels, and the manufacturing cost is very high. Therefore, people have been looking for a method that can not only meet the requirements of basic mechanical properties, but also obtain precision-sized ceramic parts by machining. In the 1990s, Japanese scholar Niihara and others adopted Si 3 N 4 Particle-coated h-BN prepared high-strength machinable ceramic parts, which opened up a new way for the preparation of high-performance machinable ceramic parts; in 2002, Li Yongli et al. 2 o 3 The analytical reagent CO(N 2 ) 2 and H 3 BO 3 Mixed at a molar ratio of 1:4, fully ground in a mort...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/58C04B35/622
Inventor 唐竹兴
Owner SHANDONG UNIV OF TECH