The primary material of one kind cubic boron nitride monocrystal prepares glomerocryst sintered body as initial feed
Method
Technical field
The invention belongs to cutter material manufacture field, specifically a kind of synthesis condition is low, heat-resist, toughness
The method that glomerocryst sintered body is prepared as initial feed with the primary material of cubic boron nitride monocrystal high.
Background technology
Modern mechanical process technology is just developed rapidly towards high accuracy, high efficiency, flexibility and automation direction, numerical control machine
The extremely excellent new material application of the new technique such as bed, machining center equipment and performance is increasingly extensive, and then cutter is wanted
Seek more and more higher.As a kind of environmental type high performance structures material, polycrystalline cubic boron nitride(PcBN)With its super abrasive, resistance to
The excellent properties such as burn into high temperature resistant have fully demonstrated requirement of the modern manufacturing industry to material.PcBN cutters are particularly suitable for various black
The hard turning of non-ferrous metal, realizes being ground with car generation.Not only improve and draw processing efficiency, and considerably reduce processing cost, it is main
Cut various hardened steels, tool steel, mould steel, bearing steel(HRC45-70), chilled cast iron, rich chromium cast iron, Ni-based and cobalt-based
High temperature alloy, various difficult processing grey cast-irons, other hardly possible processing black materials etc..Because cubic boron nitride hardness is far above ceramics
And hard alloy, the cutter life of preparation is 3-5 times, 5-15 times of hard alloy cutter of sintex.
At present, difficult-to-machine material is more and more, and PcBN cutters proportion in industrially developed country's instrument is using total amount is more next
It is bigger.PcBN its as cutting difficult-to-machine material main cutting tools for cutting material be cutting technology second leap.In China, hard
Alloy cutter consumption accounts for 60 % of total cutter, and high-speed steel accounts for 30-40 %, and PcBN cutters ratio shared at present is considerably less.In hair
Up to country, the potentiality of Digitized Manufacturing Technology are played using efficient cutter into common recognition.Annual consumption consumes 50 in lathe
% or so.And China's cutter consumption is only the 20-30 % of lathe consumption, this explanation cheap poorly efficient biography in China's cutter consumption
System cutter still accounts for main flow, and lathe function gives full play to far away.And it is current, under the overall background of highly-efficient processing, the efficient tool such as PcBN
Tool is just widely being received by market and is gradually substituting conventional tool, therefore, the country will be present to metal cutting PcBN
Great demand.
PcBN sintered bodies, are under high-temperature and high-pressure conditions that independent cubic boron nitride particle is bonding by sintering, are made
Whole cbn layer is sintered into high intensity cBN glomerocrysts, is a kind of high performance structural material.PcBN materials are because of manufacturer
Method and sintering mechanism are different, and its synthesis condition and properties of product have obvious difference, further, since Hall-Petch effects
Deng, nanometer cBN monocrystalline with the reduction of its size, some mechanical properties such as hardness will be improved, while being broken compared to micron order micro mist
In wearability and toughness, the aspect such as high temperature resistance has advantage to particle, will increase substantially the sintering of nanometer PcBN
Performance and cutting ability.Based on many at present using micron order monocrystalline broken material synthesis PcBN, to further improving its performance and depth
Enter to understand that the sin-tering mechanism and practical application of PcBN have limitation, therefore, answer Efforts To Develop sub-micro, the primary material of nanoscale monocrystalline
The development of sintered body.
This is just badly in need of one kind and prepares the advantageous glomerocryst nitridation of the aspects such as wearability, toughness and high temperature resistance
The method of boron sintered body.
The content of the invention
The invention aims to provide a kind of workable, product percent of pass polycrystalline cubic boron nitride high(PcBN)
Preparation method, sintering condition can be greatly lowered, while the heat resistance of polycrystalline cubic boron nitride sintered body, anti-can be improved
The performances such as impact flexibility.
The object of the present invention is achieved like this, and the method is comprised the following steps:
1., with Li3N-hBN is system, and it is primary material to use press to synthesize sub-micro, nano cubic boron nitride monocrystalline, followed by
Change and touch purification, sorting process, cBN degrees of purity reach 99.9 wt %, homogeneity is good, complete crystal form, corner are not damaged, are not passivated,
And the monocrystalline with high index of refraction, selected sub-micro, nanoscale cubic boron nitride average grain diameter >=50 nm;
2., will be put into molybdenum cup after the cubic boron nitride monocrystal and sintering aid of above-mentioned 1. middle selection uniformly mixing and assembled,
Used as anti-pollution packaging system, wall thickness is 0.08-0.2 mm to molybdenum cup, can be by uniform mixing material enclosed package, sintering aid
It is the big metal for being equal to 20 nanometers, ceramics or metal ceramic powder to use particle diameter, the metal or ceramic powders be Co, Ni, Ti,
Al、Si、TiN、TiC、B4C、La2O3In one or several;
3. the molybdenum cup that, will 2. assemble is by pre-molding, vacuum preheating, the assembling of pyrophyllite composite block cavity, high-pressure sinter
Program completes the preparation of polycrystalline cubic boron nitride.
Beneficial effects of the present invention are as follows:
1st, because the PcBN methods that prepare of the present invention are by selecting good crystalline form homogeneity, high purity sub-micro, nanometer
The primary material of cubic boron nitride monocrystal be raw material, be sintering aid system with metal or ceramic material, its had concurrently metal toughness and
The excellent properties such as the heat resistance of ceramics, heat resistance is significantly improved(More than 1300 DEG C);
2nd, method of the present invention strong operability, synthesis condition is greatly lowered, and it has important reality to reducing hammer consumption cost
Meaning.The method of the present invention will provide a kind of effective approach for the preparation of superhard cutter.
3rd, the PcBN product stabilities of synthesis are high, can be applied to the materials such as chilled cast iron, heat-resisting alloy and hardened steel
Roughing and Precision Machining field.
Brief description of the drawings
Fig. 1 is the pyrophyllite composite block cavity assembling sectional view in present invention process.
Mixed material 1, insulating trip 2, graphite heating pipe 3, graphite flake 4, copper sheet 5, conductive steel cap 6, pyrophillite with molybdenum cup
Composite block 7.
Specific embodiment
Glomerocryst boron nitride sintered body of the invention is studied for a long period of time by inventor, and obtained with reference to long-term experiment.Should
Method is that to use the sub-micro of high-quality, nanoscale cubic boron nitride monocrystal be primary material, adds sintering aid, then by being pressed into advance
Type, vacuum preheating, high pressure sintering processes, synthesize the process of glomerocryst boron nitride sintered body.
This synthetic method is further illustrated with reference to embodiment:
Embodiment 1:
1) with Li3N-hBN is system, and it is primary material to use press synthesizing submicron cubic boron nitride monocrystal, followed by changes and touches
Purification, sorting process, by equipment, preferably cBN such as laser particle size analyzer, microscope and plasma emission spectrometry instrument
Degree of purity reaches 99.9 wt %, and homogeneity is good, complete crystal form, corner are not damaged, are not passivated, and the monocrystalline with high index of refraction,
Selected submicron order cubic boron nitride average grain diameter is 0.5 um.
2) by above-mentioned steps 1) TiN0.7 grams of 1.3 grams of cubic boron nitride monocrystal choosing and sintering aid uniformly put after mixing
To enter assembled in 14.8 mm molybdenums cup, used as anti-pollution packaging system, wall thickness is 0.08 mm to molybdenum cup, can be by uniform mixing material
Material enclosed package, sintering aid particle diameter is 20 nanometers.
3) by step 2)The molybdenum cup of assembling is put into after 500 DEG C of purification heat treatment 1h of vacuum and adds by 40MPa pre-moldings
In hot graphite-pipe 3, finally part 4-6 is put into pyrophyllite composite block 7 in the lump, the size of pyrophyllite composite block 7 be 32.5 mm ×
32.5 mm × 32.5 mm, a diameter of 18 mm of synthetic cavity, the internal diameter of graphite-pipe 3 are 16 mm, 17 mm high.Pyrophyllite composite block
Carry out HTHP synthesis on cubic hinge press, synthesis condition is 4.5 GPa, 1400 DEG C, after the min of sintered heat insulating time 5
Slowly room temperature is cooled to, the PcBN sintered bodies of mm × 5 mm of Φ 14 is obtained after release.
Embodiment 2:
1) with Li3N-hBN is system, and it is primary material to use press to synthesize nano cubic boron nitride monocrystalline, followed by changes and touches net
Change, sorting process, by equipment such as laser particle size analyzer, microscope and plasma emission spectrometry instrument, preferably cBN is pure
Cleanliness reaches 99.9 wt %, and homogeneity is good, complete crystal form, corner are not damaged, are not passivated, and the monocrystalline with high index of refraction, institute
The nanoscale cubic boron nitride average grain diameter of choosing is 250 nm.
2) by above-mentioned steps 1) TiN0.6 grams of 1.3 grams of cubic boron nitride monocrystal choosing and sintering aid uniformly put after mixing
To enter assembled in 14.8 mm molybdenums cup, used as anti-pollution packaging system, wall thickness is 0.08 mm to molybdenum cup, can be by uniform mixing material
Material enclosed package, sintering aid particle diameter is 20 nanometers.
3) by step 2)The molybdenum cup of assembling is put into after 500 DEG C of purification heat treatment 1h of vacuum and adds by 40 MPa pre-moldings
In hot graphite-pipe 3, finally part 4-6 is put into pyrophyllite composite block 7 in the lump, the size of pyrophyllite composite block 7 be 32.5 mm ×
32.5 mm × 32.5 mm, a diameter of 18 mm of synthetic cavity, the internal diameter of graphite-pipe 3 are 16 mm, 17 mm high.Pyrophyllite composite block
HTHP synthesis is carried out on cubic hinge press, synthesis condition is 5 GPa, 1400 DEG C, slow after the min of sintered heat insulating time 5
Room temperature is cooled to, the PcBN sintered bodies of mm × 5 mm of Φ 14 are obtained after release.
Embodiment 3:
1) with Li3N-hBN is system, and it is primary material to use press synthesizing submicron cubic boron nitride monocrystal, followed by changes and touches
Purification, sorting process, by equipment, preferably cBN such as laser particle size analyzer, microscope and plasma emission spectrometry instrument
Degree of purity reaches 99.9 wt %, and homogeneity is good, complete crystal form, corner are not damaged, are not passivated, and the monocrystalline with high index of refraction,
Selected submicron order cubic boron nitride average grain diameter is 1 μm.
2) by above-mentioned steps 1) 1.9 grams of the cubic boron nitride monocrystal and 0.06 gram of sintering aid Al, 0.02 gram of Co chosen,
B40.02 gram of C is assembled during 14.8 mm molybdenums cup is put into after uniformly mixing, and used as anti-pollution packaging system, wall thickness is molybdenum cup
0.08 mm, can be by uniform mixing material enclosed package, and sintering aid average grain diameter is 1 μm.
3) by step 2)The molybdenum cup of assembling is put into after 500 DEG C of purification heat treatment 1h of vacuum and adds by 40 MPa pre-moldings
In hot graphite-pipe 3, finally part 4-6 is put into pyrophyllite composite block 7 in the lump, the size of pyrophyllite composite block 7 be 32.5 mm ×
32.5 mm × 32.5 mm, a diameter of 18 mm of synthetic cavity, the internal diameter of graphite-pipe 3 are 16 mm, 17 mm high.Pyrophyllite composite block
Carry out HTHP synthesis on cubic hinge press, synthesis condition is 5.5 GPa, 1450 DEG C, after the min of sintered heat insulating time 5
Slowly room temperature is cooled to, the PcBN sintered bodies of mm × 5 mm of Φ 14 is obtained after release.