CBN coating reachs the application that its get on in cutting tool

5min, and use GC1025 and GC015 coating razor blade to make handling time shortens further 1.

25min and 1min. Analyse through undertaking to machining a process knowable, should raise cutting rate, reduce cutting cost, in all treatment element most economic method uses data of new-style cutting tool namely. Coating of cutting tool surface is to raise the cutting tool life, significant step that reduces cutting cost. Cutting tool coating can raise the exterior hardness of cutting tool not only, enhance its wearability, and can reduce coefficient of friction of cutting tool surface, increase lubricant capacity, raise cutting rate, reduce the number that change a knife, rise to be machined the precision of the spare parts and exterior quality, improve manufacturing efficiency thereby. Current, in industrial developed country, coating cutting tool already occupied the 80% above that use all cutting tool, and our country this one scale still not as good as 20% , because this popularizes the application of coating cutting tool, development,material of new coating cutting tool has great sense. CBN(Cubic Boron Nitride, cubic nitrogen changes boron) it is another kind when after afterwards synthesizes diamond artificially, appear exceeds hard inorganic material, it besides have a lot of as similar as diamond exceedingly good physics, chemical character, like freeboard hardness (be next to diamond) , tall wearability, low coefficient of friction, small hot coefficient of expansion, the character that still has diamond of a few excel at the same time (the function contrast of CBN and diamond sees) issueing a list. Do not suit to machine steely material to differ with diamond, CBN is right metal of iron a group of things with common features has very stable chemical property, the accurate treatment that can be used extensively at steely goods accordingly, abrade wait. CBN is divided outside having good wear-resisting caustic performance, its hear resistance is very admirable also, fall in quite high cutting temperature also can cutting refractory steel, quench alloy of steel, titanium, and can the cold hard roll of cutting tall hardness, cementite quenchs material and wear away to cutting tool the difficult treatment material such as very serious Si-Al alloy. The crystal of diamond of CBN of function contrast function that expresses CBN and diamond crystal lattice of structural blende diamond is invariable (A ° ) 3.

615 3.

567 density (G · Cm-3) 3.

48 3.

515 microscopical hardness (stretch model of MPa) 46042~84337 >88260 is measured (GPa) 700 1000 heats up coefficient of expansion (C) 4 of × 10-6/ ° .

7 3.

1 chemical stability and Fe department metal do not react, to 1000 ° C does not oxidize to fasten metallic reaction with Fe in atmosphere, in vacuum of thermal stability of oxidation of above of C of the 600 ° in atmosphere, temperature just happens to change to the photograph of HBN from CBN to 1550 ° C in vacuum, temperature exceeds 1300 ° C, diamond begins CBN is not natural presence to transform to black lead, need relies on artificial synthesis, the traditional method that synthesizes CBN is law of high temperature high pressure. This kind of method is slashing to synthesizing a condition to ask, cost is high, and can receive CBN petty powder only, can use as only cutting tool of CBN of abrasive He Jujing. Nevertheless, because used binder, the processability of the cutting tool with this kind of high price also can be reduced greatly. Because this is pressing,need develops the price the CBN preparation technology with lower, higher quality. The preparation method BN of 2 CBN coating has 3 kinds of isomer, namely HBN, CBN and WBN. 6 nitrogen change HBN(boracic) have very as similar as black lead structure, call again " white black lead " , texture is very soft also; And the structure of CBN and function and diamond close. The person such as Inagawa is successful 1987 ground preparation the CBN with taller purity is filmy, subsequently a lot of researcher use deposit of physical gas phase in succession (PVD) and deposit of chemical gas phase (preparation of CVD) method success CBN, lifted the upsurge that studies cubic nitrogen converts boracic film in the world thereby. In a variety of preparation methods, the most typical method is plasma enhances pulse laser deposit law and heater assist law of deposit of gas phase of chemistry of radio frequency plasma. Graph 1 plasma enhances device of pulse laser deposit to pursue plasma of device of CVD of plasma of auxiliary radio frequency enhances 2 heater pulse laser deposit method pursues 1 enhance sketch map of device of pulse laser deposit for plasma. This device basically includes Nd:Y of much wave bandAG laser, plasma torch and vacuumize system. Plasma torch includes a thermionic emissive cathode (hot cathode, the filament that makes by tungsten filament is formed) with a positive pole; The high-energy laser effect that solid laser produces is in target material (on HBN) , can temperature amount to 10000: ? Chloric haying  pushs twin of shaming Nao of  coerce head steam of Zuo of  of    ; The thermionic activation that hot cathode launchs reacts aeriform N2 produces plasma N+ , it and B steam react, be in base piece on deposit BN is filmy. The action of base bias voltage is auxiliary deposit, base piece 5cm of the material that be apart from target, in deposit process base piece rotate ceaselessly. The typical requirement that plasma strengthens CBN of deposit of device of pulse laser deposit is: 10~150W of R6 incident power, base loses bias voltage 100~200V, stimulate 25J/cm2 of light energy density, deposit time 5~15min. Heater assists law of CVD of radio frequency plasma to pursue 2 heater assist sketch map of device of CVD of radio frequency plasma. The vibration of high frequency electromagnetism that radio frequency power source produces arouses reaction gas to produce plasma, park radical piece the heater of upper part is opposite on one hand base piece heat with reaction gas in order to provide more heat energy, what on the other hand heater blasts off is thermionic enhance plasma further, in order to raise rate of reaction gas dissociation; Base piece temperature through adjusting filament voltage undertakes controlling. Reaction gas is the gas mixture of B2H6 and NH3, dilute parts with tall purity H2 first before mixing to 1%~5% , press NH3:B again2H6=3:1bulk comparing mixes and carry reative cell. Obtain reative cell first before preparation spend to the fundamental vacuum that is less than 1Pa, clean a few minutes with H2. Heater assists the typical condition of CBN of deposit of law of CVD of radio frequency plasma to be: C of ° of heater temperature 1800~2200, base piece C of temperature 800~1000 ° , heater arrives base piece distance 5~15mm, 100~200W of radio frequency power. We adopt 3 application current situation and development perspective plasma enhanced legal system of pulse laser deposit to have CBN coating, the deposit requirement that the experiment adopts is: Incident power 100W, base loses bias voltage 110V, stimulate 25J/cm2 of light energy density, deposit time is 10min. Examine via infra-red spectrum, the CBN coat that discovery gets contains HBN(to its content differs along with preparation craft parameter and change not only) , and the coating of preparation and matrix adhesion strength are not strong. In fact, no matter use PVD law or CVD method, at present different level land contains the CBN coating of preparation HBN. In view of the quality of the CBN coat that can get at present, it can regard cutting cutting tool as coating only, because cutting tool coating is right,the constituent of coating does not have strict requirement. Accordingly, study in the light of CBN coating most is the application on cutting tool at present. Regard the wear-resisting of cutting tool as coating CBN film, can twice and even the service life that a few times land improves cutting tool. A lot of enterprises of the United States, Japan had a large number of investment in this respect, in order to fill the potential dominant position of material of apart hair CBN. The market that predicts to exceed hard coating tool in recent years will be achieved annual 2 billion dollar, and use a field basically center in auto industry. Because form CBN,always is very great internal stress when coating, because this CBN coating is extremely easy,fall off from matrix. Our experiment also proves, CBN coating cutting tool should be moved toward practical change, at present the biggest difficult problem is to should solve the adhesion between CBN coating and hard alloy matrix. At present relatively effective method is increase between matrix and coating transfer layer, if nitrogen changes titanium, nitrogen,change layer of silicon, rich boracic gradient to wait. Transfer an internal stress that can reduce coating significantly, raise the adhesion of coating and matrix thereby. Want to achieve practical requirement truly however, still remain further research and improved. Ma Xiying choose be close to very much with constant of CBN crystal lattice and the Ni that has structure of face heart cubic metre comes as underlay material deposit CBN coating, undertake its and Si underlay comparative, the crystal lattice constant that discovers Si underlay and CBN is broken deserve to spend be as high as 33% , and the crystal lattice constant of Ni underlay and CBN is broken deserve to spend only 1.

3% . Experimental result makes clear, the CBN filmy quality that grows on Ni underlay is better, and the film that grows on Si underlay appeared to come off phenomenon. Should splash on Si underlay shot Ni to transfer after the layer, the CBN filmy quality of preparation gets ameliorative apparently. Want the coat of CBN cutting tool with practical preparation, transfer except what need to choose ideal outside layer material, still answer to reduce the internal stress in coating as far as possible, we are trying to use method of laser heat treatment to reduce the internal stress in coating. Believe to be below the joint efforts of industry researcher, when preparation gives the coating of ideal CBN cutting tool that can solve production to be badly in need of to already was not far. CNC Milling