In lukewarm CVD, the function of TiCN coating and application

63, n0.

37) and Ti(C0.

54, n0.

46) , its contain the part that delivers the deposit below inferior now temperature to get azotic volume is higher, also explain the cent that increases the CH4 in aeriform mixture is pressed at the same time can lower deposit rate.  begins to produce reaction for 600 ℃ about in temperature, these exterior reaction maintain 900 ℃ all the time, in temperature higher case falls, even gas phase nucleate becomes very important, if TiCl3, TiCl4, CH3CN is compound,in the solid state that deputy reaction forms under 600 ℃ flabby a system of fixed quotas for grain production is tasted content deposit is inside matrix interface or infiltration coating the invalidation in can making coating is applying actually.  falls in similar requirement, the growth rate of MT-TiCN coating is coating of high temperature TiCN (the 3 ～ of HT-TiCN) 5 times, as a result of Yi Qing - the active of TiCl4 system is very tall, growth rate does not suffer the effect of base material, carbon carries coat diffuse can ignor, this is OK by microscopical the analysis of sample is confirmed, the analysis makes clear as a result, inside limits of whole coating ply C ∶ N is constant.  falls in the circumstance with inferior temperature () of about 750 ℃ , deposit is main by the surface kinetic control, and in temperature higher case falls, get material migratory control, make deposit in reactor of large industry CVD area is more than 1m2 and make coating uniformity is less than ± 15% become difficult, this kind of requirement is using low-pressure reactor merely (be less than 100mbar) and rotate the ability when gas sends into the system is contented. The performance structure of MT-Ti(CN) coating is careful to the course 5 μ of ＜ of ply of polishing, coating the scumble layer of M is sectional undertake metallographic is analysed, show it is astomatous, thicker coating its are columnar structural direction is perpendicular at the surface, also be astomatous; Scanning report lens (SEM) is right of sample rupture exterior analysis makes clear, columnar the structure does not suffer coating ply effect, but can distinguish give two different area. Stand by exterior ＜ the area of 1 μ M is mixed and disorderly permutation fine grained crystal, coping is a diameter about 0.

The needle form crystal of 1 μ M maintains in whole coating ply, did not observe other nucleus, also did not grow the crystal that be together almost; X ray analyses a specification, the crystallization direction of crystal is (111) face and (112) face; Through transmission electron microscope (TEM) observes, see be less than 0.

The fine grained of particle size of 05 μ M is taken, when deposit temperature is less than 700 ℃ , existence diffuses belt. The purpose is interrupted columnar the intent that crystal increases was not achieved, because MT-Ti(C, n) coating undertakes besmearing again, did not appear new nucleate, and the MT-Ti(C of will mechanical polish, n) coating undertakes besmearing again, appear new nucleate.  felt is in with the temperature deposit of 800 ℃ above the MT-Ti(C on hard alloy matrix, n) and HT-Ti(C, n) coating has similar adhesion (be more than 50N) about, this kind of good felt also got confirming in discontinuous cutting experiment.  MT-Ti(C, the combinative strength of N) coating and diffuse about, raise deposit temperature ameliorable union strength, have low diffusing material (like pottery and porcelain) than tall diffusing material (the steel that be like PH) requires deposit temperature wants tall.  expects to steel base material, microstructure also is affected each other with felt. If be below deposit temperature, austenite is bases, criterion the felt of coating can get ameliorative, high-speed steel of M2 pulverous metallurgy has higher bonding strength than general M2 high-speed steel, because former have more mixed and disorderly the small MC carbide that distributing, this quits axis growth is advantageous.  however, these general regulation make the problem complications as a result of the mutual influence of the following deputy reaction actually, the formation that stabilizes chloride for example (the alloy) that is like Ti and it, or the oxide that existence eliminates hard () of Gao Ge alloy, or the photograph below microtherm changes (Si Taili is special) etc, all these elements will reduce combinative intensity. MT-Ti(C of  leftover stress, the leftover stress data with N) useful coating is very finite, via measuring, the MT-Ti(C of hard alloy and steel, n) coating is to press stress, hard alloy MT-Ti(C, the stress of N) coating is lower than HT-TiN coating much, measure the TiN coating of 950 ℃ deposit with X ray law, its stress is 129MPa, and the MT-Ti(C of 880 ℃ deposit, n) coating, its stress is 12MPa, so big distinction cannot explain completely with different thermal stress.  to steel, MT-Ti(C, the stress size of N) coating, great majority depends on the heat treatment circumstance of base material, choose parameter of heat treatment process appropriately, attainable stress is the coating of 0. The mutual reaction of  matrix and coating as above, MT-Ti(C, no matter N) coating is what base material, its grow rate and coating composition are insusceptible, this makes in lukewarm chemical and deposit method agrees with those sensitive to decarbonization base material have coat, be like the WC-Co hard alloy of tall cobalt, be in in below lukewarm coating temperature, these material won't decarbonization.  however, because be in,the exterior coating that does not have binder produces crackle more easily, so the hard coating of hard alloy can reduce bending strength, to MT-Ti(C, n) coating spare parts also is such, the bending strength of around of K20 matrix coating is as follows: Without coating: Bending strength 2380N/mm2HT-Ti(C, n) coating (6 μ M) : Bending strength 1850N/mm2MT-Ti(C, n) coating (6 μ M) : Size of losing of intensity of bending strength 1930N/mm2 depends on coating ply and the deepness that coating affects matrix (transfer diffuse, ) of stomatic, decarbonization, accordingly, MT-Ti(C, n) coating than HT - Ti(C, n) coating fall in equal tenacity circumstance, its coating is thicker, such, MT-Ti(C, n) coating can get more the composition of wear-resisting. Before  coating, the surface of the spare parts is bright and clean degree affect grain to grow way only, but the felt that does not affect growth rate or coating. By exterior classics electric spark (the MT-Ti(C after EDM) is machined, n) coating structure can see, it is all round melt droplet, coating felt is on matrix and ooze in a subtle way is seamed in, can go up in the surface of any configuration accordingly have coat, but requirement coating surface is had taller bright and clean degree.  wearability is in to deposit the MT-Ti(C on steel, n) and HT-Ti(C, experiment of tatty of N) coating felt studies the result makes clear, two kinds of coating have tall wearability, want base material and coating ply likeness only, the absolute value of wearability of two kinds of coating is on same standard. But, MT-Ti(C, n) coating compares HT-Ti(C, n) coating has taller wear-resisting bead abrasiveness can, this and MT-Ti(C, n) compares HT-Ti(C, n) coating has taller hardness photograph be identical. It is Ti(C0 when both coating composition.

7N0.

When 3) , their hardness is Hv0 respectively.

25 ＝ 3000kg/mm2 and 2300kg/mm2.  corrosion resistance Ti(C, n) is right acerbity, alkaline have tall chemical stability and laziness with solvent, according to the report, it is in relative humidity 100% , temperature falls for the condition of 40 ℃ (according to DIN50017 standard) , the MT-Ti(C on Tu Zaigang, n) coating has wonderful corrosion resistance, the flawless coat in applying actually however gets hard, any blemish may be the dip corrode source to base material.  application circumstance (1) milling treatment is current, on industry use MT-Ti(C extensively already, the hard alloy razor blade of N) coating. From to PVD, HT and MT-Ti(C, contrast of milling of percussive of N) coating razor blade experiments to look as a result, MT-Ti(C, coating of PVDTiN of N) coating excel, as a result of,this is former have taller wearability than latter (hardness) with thicker coating, and HT-Ti(C of MT-Ti(CN) coating excel, n) coating, make an explanation still hard at present, their wearability difference cannot be the little difference that its bending strength is worth and MT-Ti(C only, n) coating causes without decarbonization, and often observe MT-Ti(C, n) coating is bigger to forming than high temperature coating the sensitivity of crackle is lesser. MT-Ti(C, life of N) milling cutter still accepts the obligation of matrix tenacity, want to get tall wearability, criterion base material must have better tenacity, and to HT-CVD coating, although use the base material with better tenacity to also cannot get as similar as MT-CVD coating result, because HT-CVD uses cobaltic content,the matrix with taller, better tenacity will produce the η carbide of higher content.  (2) turning treatment besmears on appropriate hard alloy matrix with MT-Ti(C, n) coating, can apply extensively at discontinuous turning (short cut bits) with successive turning (the long) that cut bits, its cutting performance is good. When using medium cutting speed to undertake machining, MT-Ti(C, wear away at the back of N) coating (VB) is reduced apparently.  MT-Ti(C, of N) coating and HT-CVD coating compound, the open up of cutting tool of coating hard alloy that has wide application range to develop new possibility. (Purpose of 3) sawing treatment uses thin PVD or CVD hard coating is improved curium piece life, its effects is very small. And use quite thick (12 μ M)MT-Ti(C, n) coating besmear curiums in M2 high-speed steel piece on, will curium later piece have vacuum heat treatment (62HRC) , its coating did not appear flake. Cutting experiment makes clear, MT-Ti(C, of N) coating curium a hacksaw of high speed of life comparing M2 piece with HT-Ti(C, n) curiums piece life raises 3 times, cutting time decreases on average 15% .  experiment still makes clear, the surface before coating prepares to have main effect to cutting tool life, this also is the step that takes generally in the application of thin hard coating.  (4) shapes by pottery and porcelain with the cutting tool that shapes at pottery and porcelain process (be like profiling or squash) knowable, pottery and porcelain is extremely of wear-resisting. It is those who overcome a tool to wear away, it is to use good base material commonly (if hard alloy or Si Taili are special alloy) . However, if want to make careful sample perhaps be those who avoid industry pattern to destroy in industry pattern, need is versed in the mould has quite tall tenacity, afore-mentioned material cannot be competent. MT-Ti(C, n) can be on the matrix of a lot of steel deposit ply 15 μ of 10 ～ the coating of M, steel can achieve high strength through heat treatment and do not form decarburized layer below coating, so potter course of study is introducing the MT-Ti(C of steel, n) coating mould, from before experience is knowable, have MT-Ti(C only, the particle size of N) coating is less than coating ply, its MT-Ti(C, n) coating just has ideal effect.  (5) casting aluminous mould discovers recently, in lukewarm (MT) coating also can be used at protecting casting aluminium mould. Because carry careful option,this is coating means is available what have leftover stress hardly is medium lukewarm (MT) coating, and this is planted coating scarcely by melt aluminium place embellish is wet.  experiment makes clear, the heat of coating makes tool steel spare parts can improve life 3 ～ 5 times, in lukewarm (the mould in use of MT) coating does not need to add lubricant, this is cast in automation in reduced a process and attainable still better cast surface quality.  conclusion already discovered now, the Ti(C of MT-CVD, n) coating applicable in need remains stress low, hard coating comparatives in large field, the coating technology that in 700 ℃ ～ the deposit inside the limits of 900 ℃ can choose optimization goes getting used to the heat treatment craft of steel.  is using MT-Ti(C, when N) coating undertakes machining, to achieve satisfactory treatment result, must choose base material carefully and make matrix surface optimization. CNC Milling