CN103864430B

CN103864430B - h-BN/Cr3C2 machinable ceramic preparation method

Info

Publication number: CN103864430B
Application number: CN201210535950.5A
Authority: CN
Inventors: 唐竹兴
Original assignee: Shandong University of Technology
Current assignee: Shandong University of Technology
Priority date: 2012-12-13
Filing date: 2012-12-13
Publication date: 2015-03-18
Anticipated expiration: 2032-12-13
Also published as: CN103864430A

Abstract

The invention relates to a h-BN/Cr3C2 machinable ceramic preparation method, which is characterized in that h-BN is adopted to coat Cr3C2 ceramic powder, cold isostatic pressing molding and hot pressing firing are sequentially performed to obtain the h-BN/Cr3C2 machinable ceramic, wherein boric acid, urea and ethanol are mixed in a sealed container according to a certain ratio to prepare an esterified solution, Cr3C2 ceramic powder is added to the esterified solution to prepare a ceramic slurry, the ceramic slurry is prepared into coated Cr3C2 powder through a spray granulator, the coated Cr3C2 powder is subjected to nitrogenization to obtain the h-BN-coated Cr3C2 ceramic powder, the h-BN-coated Cr3C2 ceramic powder is subjected to isostatic pressing to prepare a sheet blank, and the sheet blank is subjected to hot pressing under a nitrogen atmosphere and firing to obtain the h-BN/Cr3C2 machinable ceramic. The h-BN machinable ceramic has characteristics uniform phase distribution, controllable content, excellent workability, excellent mechanical property and excellent thermal property.

Description

A kind of h-BN/Cr 3c 2the preparation method of processable ceramic

Technical field

The present invention relates to a kind of h-BN/Cr ₃c ₂processable ceramic, belongs to field of ceramic preparation technology.

Background technology

Stupalith has many excellent performances, but because stupalith hardness is large, when preparing precise measure ceramic component, only have by diamond abrasive wheel grinding, manufacturing cost is very high.So people are finding a kind of method always, not only basic mechanical performance requirement can met but also the method that mechanical workout obtains precise measure ceramic component can be carried out.The nineties in 20th century, the people such as Japanese scholars Niihara adopt Si ₃n ₄particles coat h-BN prepares intensity height processable ceramic parts, and the preparation for high-performance processable ceramic parts opens a new way; 2002, Li Yongli etc. were at " the Al that nanometer BN is coated ₂o ₃the preparation of composite powder and sintering character research thereof " middle employing analytical reagent CO (N ₂) ₂and H ₃bO ₃with mol ratio 1:4 mixing, after fully grinding in mortar, with high-purity Al ₂o ₃it take dehydrated alcohol as medium that powder (median size 03 μm) puts into plastic tank together, uses aluminum oxide abrading-ball, wet-milling batch mixing, then dries (stirring) simultaneously, then ball milling, makes Al in a hydrogen atmosphere ₂o ₃-h-BN processable ceramic; The Dong Yan tinkling of pieces of jade in 2004 etc. are at " TiB ₂the preparation technology of one BN complex phase ceramic and performance study " in by TiB ₂, BN and Ni powder weighs by a certain percentage, respectively with different mixing method batch mixing, by mixed slurry dried and screened, and loaded by uniform compound and scribbles in the graphite jig of BN, be placed in plasma discharge hot pressing furnace and carry out sintering at Ar gas shielded and prepare TiB ₂-h-BN processable ceramic parts; 2009, Zhang Juxian employing boric acid and urea in " low-dielectric loss AIN pottery and the research of BN-AIN base ceramic material " mix to fire under nitrogen atmosphere with AlN powder made AlN-h-BN processable ceramic.Except Si in above-mentioned system ₃n ₄the bending strength of-h-BN processable ceramic can reach beyond 950MPa., as TiB ₂the anti-intensity of the processable ceramics such as-h-BN, AlN-h-BN also only has about 154 MPa..Therefore adopt common mixing, the bending strength of processable ceramics material prepared by chemical method h-BN coating technology is lower.

Summary of the invention

The object of the present invention is to provide one can overcome above-mentioned defect, realize preparing more high strength h-BN/Cr ₃c ₂the preparation method of processable ceramic.Its technical scheme is:

A kind of h-BN/Cr ₃c ₂the preparation method of processable ceramic, adopts the coated Cr of h-BN ₃c ₂h-BN/Cr is burnt till in ceramic powder hot pressing after cold isostatic compaction ₃c ₂processable ceramic, concrete grammar comprises the following steps:

The first step: by boric acid: urea take weight ratio as the ratio uniform mixing of 2:1, and additional 30 ~ 60% ethanol 50 ~ 90 DEG C of heat treated in encloses container stir after 10 ~ 24 hours again makes esterification solution in 10 ~ 30 minutes;

Second step: the Cr by granularity being 0.1 ~ 2 μm ₃c ₂ceramic powder 40 ~ 70% joins ball milling in the above-mentioned esterification solution of 30 ~ 60% and makes ceramic size, then by sponging granulator, above-mentioned ceramic size is made the coated Cr that diameter is 0.01 ~ 0.5mm ₃c ₂powder, by above-mentioned coated Cr ₃c ₂powder is that nitrogen atmosphere nitrogenize in 600 ~ 1000 DEG C × 30 ~ 60 minutes obtains the coated Cr of h-BN in temperature ₃c ₂ceramic powder, by coated for h-BN Cr ₃c ₂ceramic powder makes × 10 ~ 20mm flake shaped base substrate through isostatic cool pressing under the pressure of 100 ~ 200MPa., and then under 1700 ~ 1850 DEG C × 30 ~ 180 minutes nitrogen atmospheres, hot pressing 5 ~ 100MPa. is fired into h-BN/Cr ₃c ₂processable ceramic.

Compared with prior art, its advantage is in the present invention:

1, the present invention produces h-BN/Cr ₃c ₂processable ceramic uniform microstructure, intensity is high, and global reliability is high;

2, the uniform h-BN layer of thickness can be formed at Cr3C2 grain surface by this cladding process, and the thickness of h-BN layer is controlled, prepared h-BN/Cr ₃c ₂bending strength raising 1 times compared with mixing, chemical method of processable ceramic;

3, h-BN/Cr ₃c ₂processable ceramic has excellent antioxidant property, mechanical property and thermal property.

Embodiment

embodiment 1

The first step: by boric acid: urea take weight ratio as the ratio uniform mixing of 2:1, and additional 30% ethanol 50 DEG C of heat treated in encloses container stir after 24 hours again makes esterification solution in 30 minutes;

Second step: the Cr by granularity being 0.1 μm ₃c ₂ceramic powder 70% joins in the esterification solution of 30% and makes ceramic size, then by sponging granulator, above-mentioned ceramic size is made the coated Cr that diameter is 0.5mm ₃c ₂powder, by above-mentioned coated Cr ₃c ₂powder is that nitrogen atmosphere nitrogenize in 600 DEG C × 30 minutes obtains the coated Cr of h-BN in temperature ₃c ₂ceramic powder, by coated for h-BN Cr ₃c ₂ceramic powder isostatic pressed under the pressure of 100MPa. is pressed into × 10mm flake shaped base substrate, and then under 1700 DEG C × 30 minutes nitrogen atmospheres, hot pressing 5MPa. is fired into h-BN/Cr ₃c ₂processable ceramic.

The purity of testing proportion material used is technical pure, the h-BN/ Cr obtained ₃c ₂the bending strength of processable ceramic is 422MPa..

embodiment 2

The first step: by boric acid: urea take weight ratio as the ratio uniform mixing of 2:1, and additional 45% ethanol 70 DEG C of heat treated in encloses container stir after 16 hours again makes esterification solution in 20 minutes;

Second step: the Cr by granularity being 1 μm ₃c ₂ceramic powder 55% joins in the esterification solution of 45% and makes ceramic size, then by sponging granulator, above-mentioned ceramic size is made the coated Cr that diameter is 0.2mm ₃c ₂powder, by above-mentioned coated Cr ₃c ₂powder is that nitrogen atmosphere nitrogenize in 800 DEG C × 45 minutes obtains the coated Cr of h-BN in temperature ₃c ₂ceramic powder, by coated for h-BN Cr ₃c ₂ceramic powder isostatic pressed under the pressure of 150MPa. is pressed into × 15mm flake shaped base substrate, and then under 1800 DEG C × 105 minutes nitrogen atmospheres, hot pressing 50MPa. is fired into h-BN/Cr ₃c ₂processable ceramic.

The purity of testing proportion material used is technical pure, and the bending strength of the h-BN/Cr3C2 processable ceramic obtained is 399MPa..

embodiment 3

The first step: by boric acid: urea take weight ratio as the ratio uniform mixing of 2:1, and additional 60% ethanol 90 DEG C of heat treated in encloses container stir after 10 hours again makes esterification solution in 10 minutes;

Second step: the Cr by granularity being 2 μm ₃c ₂ceramic powder 40% joins in the esterification solution of 60% and makes ceramic size, then by sponging granulator, above-mentioned ceramic size is made the coated Cr that diameter is 0.01mm ₃c ₂powder, by above-mentioned coated Cr ₃c ₂powder is that nitrogen atmosphere nitrogenize in 1000 DEG C × 60 minutes obtains the coated Cr of h-BN in temperature ₃c ₂ceramic powder, by coated for h-BN Cr ₃c ₂ceramic powder isostatic pressed under the pressure of 200MPa. is pressed into × 20mm flake shaped base substrate, and then under 1850 DEG C × 180 minutes nitrogen atmospheres, hot pressing 100MPa. is fired into h-BN/Cr ₃c ₂processable ceramic.

The purity of testing proportion material used is technical pure, the h-BN/Cr obtained ₃c ₂the bending strength of processable ceramic is 360MPa..

Claims

1. a h-BN/Cr ₃c ₂the preparation method of processable ceramic, is characterized in that: adopt the coated Cr of h-BN ₃c ₂h-BN/ Cr is burnt till in ceramic powder hot pressing after cold isostatic compaction ₃c ₂processable ceramic, concrete grammar comprises the following steps:

The first step: by boric acid: to take weight ratio as the outer in addition weight percent of the ratio uniform mixing of 2:1 be urea that 30 ~ 60% ethanol, 50 ~ 90 DEG C of heat treated in encloses container stir after 10 ~ 24 hours again makes esterification solution for 10 ~ 30 minutes;

Second step: the Cr by granularity being 0.1 ~ 2 μm ₃c ₂ceramic powder is that 40 ~ 70% to join with weight percent be that in the above-mentioned esterification solution of 30 ~ 60%, ball milling makes ceramic size with weight percent, then by sponging granulator, above-mentioned ceramic size is made the coated Cr that diameter is 0.01 ~ 0.5mm ₃c ₂powder, by above-mentioned coated Cr ₃c ₂powder is that nitrogen atmosphere nitrogenize in 600 ~ 1000 DEG C × 30 ~ 60 minutes obtains the coated Cr of h-BN in temperature ₃c ₂ceramic powder, by coated for h-BN Cr ₃c ₂ceramic powder makes × 10 ~ 20mm flake shaped base substrate through isostatic cool pressing under the pressure of 100 ~ 200MPa., and then under 1700 ~ 1850 DEG C × 30 ~ 180 minutes nitrogen atmospheres, hot pressing 5 ~ 100MPa. is fired into h-BN/ Cr ₃c ₂processable ceramic.