Background technology
In recent years, because Ti (C, N) based ceramic metal has good wear resistance, high hot hardness, better oxidation-resistance and high temperature creep-resisting energy, be subject to people and more and more paid close attention to.In addition, the main raw material of making traditional Wimet is WC and Co, they are all rare strategic resources, and Ti (C, N) main raw material of based metal ceramic cutter material is Ti, Ti reserves are on earth W 70 times 131, therefore there is great cost and resources advantage compared with traditional Wimet.But the intensity of Ti (C, N) based ceramic metal and toughness but, lower than traditional WC-Co series hard metal, have seriously limited ceramic-metallic application.If we can, in the case of not reducing Ti (C, N) based ceramic metal premium properties, improve its intensity and toughness, Ti (C, N) based ceramic metal will become the good cutting material that substitutes of traditional WC-Co series hard metal so.Therefore, according to Hall-Petch formula, utilize ultrafine powder to prepare superfine Ti (C, N) based ceramic metal is more and more with the research of the obdurability of raising material, but the technology of current existing preparation TiCN powder is not that raw materials cost is high, equipment complexity is exactly that quality product is low, is difficult to obtain high, the even-grained high quality superfine Ti of purity CN powder.
At present, the method for preparing TiCN powder body material comprises: by carbodynamite at 1100 DEG C of pyrolytic decompositions; Utilize nano TiN and carbon black to react in the argon gas stream of 1300 DEG C; Adopt sodium Metal 99.5 at 600 DEG C of reduction C
3n
3cl
3and TiCl
4mixture; Combine sol-gel technique and the carbothermic reduction technology (1550 DEG C) of using; Utilize gac in the nitrogen of 900~1500 DEG C, to reduce TiO
2; Utilize titanium and carbon in nitrogen, to carry out self-propagating high-temperature reaction; Ball milling TiO in nitrogen for a long time
2, graphite and aluminium powder.And the method for the existing TiCN of preparation powder is all one section of reaction, and raw materials cost is high, and equipment complexity or quality product are low, is difficult to obtain that purity is high, granularity is little, the high quality TiCN powder of even particle size distribution.
Summary of the invention
For deficiency of the prior art, the present invention aims to provide a kind of method of preparing super fine titanium carbonitride, the principal feature of the method is to adopt organic carbon source, vacuum reducing carbonization fast in vacuum oven, prepared superfine Ti CN powder body material purity is high, impurity is few, granularity is less than 1 micron, and pattern is spherical, even particle size distribution, and cost is low, technique is simple.
For achieving the above object, the technical solution adopted in the present invention is:
Prepare a method for super fine titanium carbonitride, concrete steps are:
(1) by nano-TiO
2mix wherein nano-TiO with organic carbon source ball milling
2with the mass ratio of contained C in organic carbon source be 10:1~4.8, then cold pressing and make piece material;
(2) described block of material packed in vacuum induction furnace, be evacuated to furnace pressure and be less than or equal to 50Pa, be then warming up to 300 DEG C-800 DEG C with the heat-up rate of 5 DEG C/min-8 DEG C/min, insulation 0.5 h-3h; Be warming up to 1000 DEG C~1900 DEG C, insulation 0.5 h~3h, constantly vacuumizes in insulating process again;
After (3) (2) steps finish, pass into nitrogen, making furnace pressure is 1.1-1.2 normal atmosphere, continue to be incubated 1 h~4h at 1000 DEG C~1900 DEG C, make the abundant nitrogenize of raw material, be then cooled to 150 DEG C~350 DEG C, take out piece material, fragmentation, ball milling, classification, obtain the carbon titanium nitride powder material that Fisher particle size is less than 1 micron.
The described nano-TiO of step (1)
2preferred Fisher particle size is less than 100 nanometers, TiO
2content is greater than 99%.
The carbon source of the described carbon source of step (1) is selected from polyvinyl alcohol, sucrose, starch, tartrate, oxalic acid or glucose.
The described nano-TiO of step (1)
2be preferably 10:2~4 with the mass ratio of contained C in carbon source.
In preferred steps (2), described block of material packed in vacuum induction furnace, be evacuated to furnace pressure and be less than or equal to 50Pa, be then warming up to 350 DEG C-650 DEG C with the heat-up rate of 5 DEG C/min-8 DEG C/min, insulation 0.5 h-2h; Be warming up to again 1100 DEG C~1700 DEG C, insulation 0.5 h~2h.
The speed heating up again of step (2) does not have particular requirement, so that 3 DEG C/min-8 DEG C/min is better.
The described nitrogen gas purity of step (3) is preferably greater than 99%.
Below the present invention is further explained and is illustrated:
Principle of the present invention comprises decomposes coated, reduction and nitrogenize three phases: the 1st, and the decomposition of organic carbon source is coated, pack in vacuum induction furnace by described block of material, be evacuated to furnace pressure and be less than or equal to 50Pa, then be warming up to 300 DEG C-800 DEG C with the heat-up rate of 5 DEG C/min-8 DEG C/min, insulation 0.5 h-3h.The 2nd, step of reaction, is warming up to 1000 DEG C~1900 DEG C again, and insulation 0.5 h~3h, constantly vacuumizes in insulating process.The 3rd, the nitrogenize stage, i.e. insulation stops vacuumizing after finishing, and passes into nitrogen, and making furnace pressure is 1.1-1.2 normal atmosphere, and insulation 1 h~4h, makes the abundant nitrogenize of raw material, is then cooled to 150 DEG C~350 DEG C, takes out piece material.
In the coated stage of decomposition of organic carbon source, under vacuum state, organic carbon source melts, decomposes, and generates fine carbon black, is enclosed in uniformly TiO
2particle surface can play the effect of foaming in the time of organic carbon fusing, decomposition, is that material piece is loose, is conducive to the mass transfer of nitrogen; Organic carbon produces superfine carbon granule while decomposition, surround uniformly around Nanometer Titanium Dioxide particle, not only can make carbon react fully fast at lower temperature with titanium white, the more important thing is because the coating function of carbon makes can directly not contact between titanium white particle, thereby suppressed growing up of particle.
At reduction phase, be warming up to 1000 DEG C~1900 DEG C, by titanium white (TiO
2) fully reduction, excess carbon reduction TiO under vacuum state
2chemical equation be TiO
2+ (2+x) C=Ti
y+ Ti
(1-y)c
x+ 2CO, wherein 0≤y≤1,0≤x≤1.The CO simultaneously generating due to reaction is pumped rapidly, has also promoted carrying out rapidly and thoroughly of reaction, and O content is wherein reduced to and is less than 1%.
In the nitrogenize stage, work as TiO
2after fully being reduced by carbon, stop vacuumizing, pass into nitrogen, and make furnace pressure be slightly larger than a normal atmosphere, the metal Ti that at this moment reduction generates starts to react with nitrogen rapidly, generates titanium nitride, and its reaction formula is 2Ti+N
2=2TiN, the Ti that TiN generates with reduction phase again simultaneously
(1-y)c
x, wherein 0≤y≤1,, there is solid solution reaction, thereby generate single-phase TiCN material in 0≤x≤1.
Compared with prior art, advantage of the present invention is:
1, method of the present invention comprises and decomposes coated, reduction and nitrogenize three phases, the quality product obtaining is high, prepared superfine Ti CN powder body material purity is high is more than or equal to 99%, O content lower than 1%, few, the Fisher particle size of impurity is less than 1um, pattern is spherical, even particle size distribution.
2, method technique of the present invention is simple, and equipment requirements is low, cost is low, energy expenditure is less, be convenient to the advantage of large-scale commercial production.
Embodiment
Below in conjunction with embodiment, the present invention is described further.
embodiment 1:
Prepare a method for super fine titanium carbonitride, adopt TiO
2with starch be raw material, by 100kg TiO
2evenly mix (wherein nano-TiO with 87.5kg starch
2mass ratio 10:3.85 with institute's carbon containing in organic carbon source), cold pressing and make piece material, pack in vacuum oven, speed with 5 DEG C/min heats up rapidly, and vacuumizes simultaneously, makes vacuum tightness be less than 50pa, when temperature rises to after 700 DEG C, insulation 1h, while then continuing to rise to 1500 DEG C, insulation 2h, then stops vacuumizing, and passes into continuously nitrogen, making furnace pressure is 1.1 normal atmosphere, 1500 DEG C time, after nitrogenize 2h, stop heating, make product furnace cooling.Product TiCN content is that 99.2%, O content is 0.9%, and Fisher particle size is 0.93um, and SEM pattern is spherical, and even particle size distribution is shown in Fig. 1, Fig. 2.Fig. 3 and Fig. 4 are the SEM figure of German Stratco Inc. like product.By Fig. 1 and Fig. 3 contrast, Fig. 2 and Fig. 4 contrast, known, the prepared product SEM pattern of the present invention is spherical, size-grade distribution is more even.
embodiment 2:
Prepare a method for super fine titanium carbonitride, adopt TiO
2with polyvinyl alcohol be raw material, by 100kg TiO
2evenly mix (wherein nano-TiO with containing 76.8kg polyvinyl alcohol
2mass ratio 10:4 with institute's carbon containing in organic carbon source), cold pressing and make piece material, pack in vacuum oven, speed with 5 DEG C/min heats up rapidly, and vacuumizes simultaneously, makes vacuum tightness be less than 50pa, when temperature rises to after 650 DEG C, insulation 1h, while then continuing to rise to 1520 DEG C, insulation 2h, then stops vacuumizing, and passes into continuously nitrogen, making furnace pressure is 1.1 normal atmosphere, after 1520 DEG C of nitrogenize 3h, stop heating, make product furnace cooling.Product TiCN content is that 99.1%, O content is 0.8%, and Fisher particle size is 0.96um.