2 vulcanization molybdenum " soft " the research progress of coating cutting tool and application
- source:EAGLEBURGER CNC Machining
001, showed the superior performance with MoS2 peculiar anti-friction, lubricant place adequately. On the other hand, the blemish of MoS2 is very apparent also: When temperature exceeds 400 ℃ MoS2 begins oxidation namely, and be deepened gradually as the elevatory oxidation degree of temperature, at the same time lubricant function drops quickly, its reason is material produced attrition chemistry to react, generated horniness grain MoO3, increased coating wear away. MoS2 is very sensitive to environmental humidity, what easy moisture absorption causes coefficient of friction directly is elevatory, come by 10% litres when environmental relative humidity 90% when, its coefficient of friction increases nearly one times. In addition, moS2 follows test environment and the change that contact a condition, its performance produces wave motion easily still. These defect of MoS2 make its use the restriction with get certain further. Current, the function that around improvement MoS2 reachs its coating, raise MoS2 " soft " the heat problem such as the application of coating cutting tool in cutting treatment, domestic and international scholar undertook the research of many sided and exploration. 2 MoS2 " soft " the physico-chemical performance that the domestic and international progress that coating studies affects the element of coating function to have coating material itself not only, the put in order that still includes matrix changes craft of function, coating and matrix and coating between, between coating and coating match each other etc. These influencing factor can be divided for the following two respects. The choice matrix of matrix serves as the body propping up of coating, self-evident to the influence of coating function, decide the success or failure of coating craft directly even sometimes. Matrix and coating should manage in content function and chemical performance side match each other, want to consider matrix to whether have tall hardness, the parameter such as stretch model quantity, hot coefficient of expansion is reasonable and have with coating wait without chemical reaction. The contrast such as Jing Yang in ZL108 aluminium alloy (110HV) of 90 ～ and the MoS2 relative to the preparation on harder 1Cr18Ni9Ti(370HV) data are compound of coating microscopical hardness value, the hardness that discovers latter compares close 1/5 of former tower above times. After the author is analysed, think, the matrix of tall hardness produces plasticity not easily to be out of shape, because matrix plasticity is out of shape the coating that cause is torn off prematurely,can defer and flake, its action is similar to the horniness in much coating and compound coating intermediate layer, support action to arriving since exterior layer thereby; At the same time of compound coating microscopical hardness also gets rising apparently. What coefficient of expansion and stretch model quantity heat up between matrix and coating or coating and coating is different, can bring about size of the existence between coating interface to differ, distributing not all leftover stress field. Jing Yang in TiN-MoS2/TiN of deposit of YG8 and gas phase of YT14 surface physics after compound coating, discover a layer, base the leftover stress condition between all shows remains to pull stress, matrix to show remains to press stress for coating, its reason is to heat up DYG8 of ＞ of DTiN of coefficient of expansion or DYT14 (to see watch 1) . And the stress condition of final coating interior is: The remains of YT14 matrix presses stress to reduce, and because YG8 matrix compares difference of both hot coefficient of expansion with TiN coating photograph bigger, press stress to disappear not only consequently, still arise to pull stress certainly, around stress condition produced change. The existence of leftover stress field affected the adhesion between coating and matrix, and layer, base hot coefficient of expansion differs bigger, leftover stress is greater also, layer, base the adhesion between is lower, its get used to the ability of environment of wide difference in temperature to also jump over difference. Because this is when choice matrix, should choose to heat up the material with the parameter such as coefficient of expansion and stretch model quantity and matrix lesser difference as far as possible, reduce leftover stress thereby, raise the adhesion between coating interface. Document still had the test of deposit MoS2/TiN in Cu and carbolic steel surface, result coating fails. After the author is analysed, discover, coating and matrix produced chemical reaction in deposit process, the CuO that contains in impure Cu and connect deposit and indoor H2S gas to decompose the H+ response that give to make steam, produced ill phenomenon of so called hydrogen: Cu2+ + H2O of → of CuO + 2H+ expands when lunt when, make the grain that already formed produces burst, bring about Cu matrix surface to appear 0.
The indentation that 5mm controls, make coat basic cannot go on deposit. To the experiment of carbolic steel matrix the analysis also has similar conclusion. Because this chooses,the layer considers even when matrix, base the chemical function between matchs. Need an attention is, the data that uses chemical function close is gradational form transfer layer (gradient coating) , already was applied extensively in much coating and compound coating: The material with more contiguous property matchs performance more reasonable, the adhesion between coating interface is stronger, form move film more easily, wearability is better, thereby the life of soft coating is longer also. The hardness of parameter of performance data material that expresses a few kinds of 1 matrix and coating material (HV) heats up coefficient of expansion (× 10-6mm/mm ℃ ) coating MoS2 400 10.
7 matrix or steel of M42 of intermediate layer high-speed steel are common twist drill ≈ of 860740 ± 30 YG8YT14 14001500 4 of 12 hard alloy.
TiNSi3N4 25001600 9 of 5 pottery and porcelain.
4 watches the 1 hardness that listed MoS2 and a few kinds of matrix and intermediate coating data and value of hot coefficient of expansion. Cent of method of coating of MoS2 of method of coating of MoS2 coating craft is deposit of chemical gas phase (CVD) law and deposit of physical gas phase (PVD) law. Compare with CVD law photograph, temperature of processing of PVD coating method is low, coating interior condition is press stress, suit hard alloy nicety more coating of complex cutting tool, and do not have adverse effect to the environment, accord with the development way that contemporary green makes. Use PVD law to be splashed mediumly more at present shoot technology, ionic plating technology (or both photograph is united in wedlock) preparation MoS2 " soft " coating. However magnetism accuses to splash shoot MoS2 coating to regard current main trend as deposit method, acquires coating quality and deposit rate all the time hard satisfactory. The development such as Teer goes a kind to be called to close magnetism of balance of magnetic field blame accuses to splash shoot ionic plating (the deposit method of CFUBMSIP) , applying stage by stage " soft " among the preparation of coating. Graph 1 for its structure sketch map. Graph 1 close magnetism of balance of magnetic field blame accuses to splash shoot ionic plating sketch map of construction of system raises magnetism to accuse to splash the ion when shooting to shed density is improvement splash the key that shoots coating function and efficiency. Ionic generation uses balance magnetism to control a source at first, the characteristic of CFUBMSIP system is in vacuum indoor platoon cloth used blame balance magnetism to control a source, the magnetism of adjacent of the photograph in the system accuses polarity of source magnetic field contrary, make whole vacuum indoor existing annular magnetic field, 2 times the electron is at large cannot fly to positive pole directly after the pit that gives magnetic field of parallel of surface of cathode target material, fall to close with approximate and cycloidal motion again however in the trap of magnetic field, increased the collision odds of electron and aeriform element thereby, the ion that the ionization rate that raised gas substantially and cathode target can get sheds density, make the system is had taller splash firing rate to lead. Watch 2 be in to use this system the MoST(MoS2 + metal of preparation of M42 steel surface or compound) the function of compound coating and pure MoS2 coating is compared, the performance that sees compound coating is obtained rise significantly. Compound coating of watch 2 MoST and function of pure MoS2 coating compare parameter hardness (wear rate of HV) coefficient of friction (M3/Nm) pure MoS2 400 0.
08 ～ 0.
2000 0 of ～ of 10-5 MoST 1000 of × of 15(RH 50%) 4.
02 ～ 0.
＜ of 1(RH 40%) is concerned in the combinative material progress such as name of Han Cheng of 4 × 10-7 " polyphase material " concept, put forward a kind of blame to balance accept rice law of compound plasma plated film (NCUPP) , its principle is to be below specific craft parameter requirement, use gas discharge makes gas or ionization of material be evaporatinged, produce ionic bombard while evaporate content or other reactant deposit are on matrix. The material that this means can reach ten kinds to differ to a few kinds has careful accept rice compound, make in 2 ～ the bag in the coating with 3 μ thick M contains a few, even rice of ten polyphase accept is compound layer. Its design a principle to see a picture 2. Graph author of plan of system of standard of compound plasma plated film uses rice of accept of 2 blame balance this method is right a few kinds of material (Ti, N, Mo, S) had careful accept rice compound, in 1Cr18Ni9Ti stainless steel steel piece with the preparation on broach of F8 fried dough twist compound coating of rice of TiN-MoS2/Ti heterogeneous accept. X photoelectron can chart appearance (XPS) experiment shows, partial Ti exists with the form of oxide, compact oxidation film was formed in coating surface, prevented coating to oxidize further, raised accept rice thereby of compound coating fight damp oxidation ability. Wear away comparative experiment makes clear: The coefficient of friction of compound coating follows accept rice scarcely wear away of life change and change, the rice of TiN-MoS2/Ti polyphase accept that the specification uses NCUPP law deposit is compound " soft " of coating wear away life far outclass is common TiN-MoS2/Ti coating. Each parameter of craft of coating craft coating is affected likewise " soft " the adhesion of coating interface, affect the integral performance of coating then. These parameter include: Negative bias of current density of Ar atmospheric pressure, cathode, matrix and magnetism accuse to splash shoot a condition (target is apart from, the accretion of metal or compound is measured etc) etc. Express the 3 craft parameter that make compound coating of rice of equipment TiN-MoS2/Ti accept to use NCUPP method. Vacuum of layer of deposit of parameter of compound coating craft spends rice of accept of watch 3 TiN-MoS2/Ti (Pa) atmosphere (Pa) bias voltage (V) target electric current (A) deposit time (Min) temperature (℃ ) 10-2 N2(0 of TiN 2 × .
10-2 Ar(0 of × of 5) 200 80 30 200 MoS2/Ti 2.
15 200 150 70 90 80 of target of Ti of target of Mo of target of Ti of 5) Mo target had document to inspect Ar atmospheric pressure, magnetism to control the power source mode, impact that splashs cold trap of type ejaculation target, liquid nitrogen to wait for pair of coating function. The result makes clear: In inferior Ar atmospheric pressure (it is in the experiment 0.
40Pa) lays acquisition coat, its function excel is more high-pressure (0.
88Pa) lays acquisition coat; Use coating of preparation of only direct current source wear away the coating that bulk is more than double pulse direct current source to fall; Of coating of the preparation below condition of liquid nitrogen cold trap wear away bulk is less than the coat that without liquid nitrogen cold trap lays; Relative humidity and Ar atmospheric pressure are inferior (0.
Below the condition of 40Pa) , of the coating of cold target preparation wear away bulk is tallish at heating up target, but contrary to coating of depressive of taller Ar gas, if pursue,3 are shown. (A)Ar atmospheric pressure is 0.
40Pa (b)Ar atmospheric pressure is 0.
Of the MoS2 coating that 88Pa graph obtains below atmospheric pressure of 3 different Ar, cold or hot target wear away bulk (of the broach when content of A) different Ti get cut life (B) different deposit is baric of head of run the drilling tool into the well auger cut life to pursue 4 different parameter get those who cut life to broach, made an on-the-spot investigation to use NCUPP law to be in the function of the TiN-MoS2/Ti compound coating of preparation of surface of twist drill of F8mm 6542 steel, and this coating function and magnetism accuse to splash shoot a condition (target is apart from, deposit atmospheric pressure and Ti additive content) the relation between. After the author studies, discover, of coating cutting tool auger cut life and Ti content direct and relevant, but be not show linear growth as the accretion of Ti content, it is about in Ti content however 12.
5% when achieve highest (4a seeing a picture, number of the biggest bore is 310) in the experiment. Reduce the addition with deposit atmospheric pressure as what target is apart from, ti content increases subsequently, had been apart from when target small (be less than 50cm) , deposit atmospheric pressure too big (more than 3.
When 0Pa) , ti content increases significantly, the result causes the crystal lattice inside coating to produce serious distortion, distortion can mushroom, the wear-resisting life that causes coating is reduced quickly, lose due lubricant effect (4b) seeing a picture. Author classics concludes after the experiment for many times: Use target to spur 50cm, deposit atmospheric pressure 3.
Right now Ti content makes an appointment with 0Pa(12.
The compound coating property that obtains when 5%) is optimal. In addition, it is OK to undertake be splashinged beforehand ejaculation cleaning to matrix before deposit the impurity that eliminate goes against coating and matrix union, to MoST coating, clean a process while open a metal to splash shoot target () of the target that be like Ti, still can reduce vacuum the chroma of indoor vapor; Bias voltage is lost certainly to undertake ionic bombard to coating through bringing to bear on to matrix in deposit process, can raise a layer, base of constituent diffuse each other the nuclear reaction of ability and coating surface is active, can reduce the generation of the blemish in coating thereby. Consider above factor integratedly, document is in Ar atmospheric pressure 0.
10A/cm2 of current density of 40Pa, cathode, bring to bear on at the same time - below the condition that 100V loses bias voltage to undertake ionic bombard, obtained the MoS2 coating with lowest of the coefficient of friction in the experiment and wear-resisting best function. 3 MoS2 " soft " the applied effect of coating cutting tool pursues the workpiece surface quality after the contrast of average milling force when the stainless steel of 5 AISI 304 of Duan Xi of coating cutting tool that differ two kinds to use and treatment (cutting dosage: V=150m/ Min, f=0.
04mm/r, ap=4mm) . See by the graph, the hard alloy milling cutter of coating of deposit on TiCN MoST is doing attrition condition to issue average milling force to be reduced significantly, treatment surface quality also wins marked improvement. The influence of two respects makes the amount of end item and quality all are obtained rise apparently. (A) cutting tool is average cutting force (the coating cutting tool that plan of quality of surface of B) workpiece treatment differs two kinds 5 applies effect contrast to pursue the bore amount of broach of 6 different coating pursues quite the contrast of rate of cutting tool cutting of 7 different matrix and coating pursues 6 compare for numerary of bore of broach of 3 kinds of high-speed steel coating: V=30m/min, f=0.
12mm/r; Workpiece is) of JIS S50C steel. See by the graph, deposit on hard coating TiN a MoST " soft " the broach after coating, its life rose than using the bit of TiN coating alone 2.
1 times, rose than TiAlN coating broach 2.
8 times. Document discussed MoST " soft " the limitation of coating application. After turning experiments, in the hot influence of bit the area discovers oxygen existence, the oxidation that shows because comparative,in turning process high cutting temperature caused coating wears away. The author thinks from this: MoST " soft " coating does not apply to craft of turning of successive high speed; When low speed milling, moST " soft " the life of coating cutting tool is compared normally not coating cutting tool is tall 1.
15 ～ 2 times. Wraparound will tell, moST " soft " coating cutting tool agrees with low speed interrupted cutting. Graph the 7 cutting tool that are different matrix and coating carry mill to forging the contrast of rate of the cutting when aluminium alloy spare parts. See by the graph, the cutting rate of the high-speed steel cutting tool of exterior deposit MoS2 rose 2 times than hard alloy cutting tool, than not cutting tool of coating high-speed steel raised 6 times. (A) cutting 1045 carbon steel (B) cutting 302 stainless steel pursue 8 have / the cutting tool of pottery and porcelain that does not have MoS2 coating wears away life contrast pursues 8 to have / 1045 steel mix the cutting of cutting tool of pottery and porcelain that does not have MoS2 coating when 302 steel wear away life is comparative (cutting dosage: V1045=180m/min, v302=103m/min, f=0.
25mm) . See by the graph, cutting when 1045 carbon steel, the Si3N4 of deposit MoS2 and cutting tool of Ti(CN) pottery and porcelain wear away life is lengthened than having coating cutting tool 50% ; Cutting when 302 stainless steel, the WC of besmear Fu MoS2 base cutting tool of pottery and porcelain wears away life is lengthened than having coating cutting tool 140% . 4 epilogue MoS2 " soft " the research development of coating cutting tool offerred new thinking to improve the cutting performance of cutting tool. Introduce the coefficient of friction when MoS2 soft coating can reduce cutting tool cutting significantly, reduce cutting tool wear away, prolong cutting tool life. Close magnetism of balance of magnetic field blame accuses to splash shoot ionic plating and rice of blame balance accept the development of the coating method such as compound plasma plating, and through logical choice matrix, optimize deposit craft, before undertaking proper matrix, technology and the measure such as the aftertreatment make the MoS2 of preparation " soft " coating structure is more compact, the adhesion between coating and matrix increases, cutting tool life is lengthened. Combine accept rice technology and compound coating technology, extend new MoS2 coating technology, optimize coating craft parameter further, expand " soft " the cutting test range of coating cutting tool and applied limits, discuss further at the same time " soft " coating attrition abrasiveness can obtain the mechanism that rise, will be henceforth the MoS2 inside a paragraph of period " soft " the development way that coating cutting tool studies. CNC Milling CNC Machining