The method of magnetic and abrade polish of diamond film studies

Foreword diamond film has superior performance, it is the ideal coating of material of cutting tool, mould, as deposit of chemical gas phase (the development of CVD) technology, the manufacturing cost that uses film of diamond of complex of this kind of technology is being shown reduce, had had commercialized applied perspective [1] . But dimension of the orientaton of the surface of groovy diamond film, grain and ply are inhomogenous, exterior surface roughness is taller also, can amount to a few micron commonly, affected a lot of application of diamond film. For example, cutting tool of diamond film coating and mould ask to have faster face bright and clean degree, consequently the later period processing technique of diamond (include polishing, level off, metallization to wait) become more and more important. filmy to diamond polish, because its hardness is tall, chemical performance is steady, and ply is thinner, and in polishing process produce diamond film extremely easily to flake, because the polishing problem of this diamond film already was become,enlarge the crucial technology that diamond film uses. In recent years, domestic and international scholar passes much research and test, offerred the polishing means of a lot of new diamond film, the bag is comfortable chemical and auxiliary mechanical polish, laser polish, thermochemistry polish, ionic bundle of polish, electric spark polish [2-6] . These methods basically were to use carbolic atomic to diffuse with evaporate and the graphitization of chemical reaction, small cutting, surface polish that will realize diamond film. Because magnetism is abrade " magnetism is brushed " it is flexible, suit very much inside the polish of aperture [7] . The article put forward to use the new method of film of diamond of the aperture inside magnetic and abrade polish, study the velar surface configuration of its polish around, quality and performance, discuss the characteristic of film of magnetic and abrade diamond and result. 2.

Experiment method 　 2.

The principle with 1 abrade magnetism is shown 1 times like the graph, a magnetic field was formed between magnetic pole N and S. If in magnetic field fill has magnetism one kind to have the abrasive of cutting ability again already, abrasive general along lines of force close together ground, well-regulated ground is arranged rise, form brush state namely so called " magnetism is brushed " , generate constant pressure to workpiece surface. Enter this magnetic field when work place in, this " magnetism is brushed " can produce magnetic force and be in with the formal function of pressure workpiece apparently. Undertake when workpiece whirligig and axis move, magnetic force is abrade brush and opposite motion produces between workpiece, undertake to surface of the aperture inside workpiece thereby abrade. In magnetic and abrade process, odd grind bead to be mixed in retentivity of magnetic field active force, magnetic field tangential below the joint action of attrition force, make grind bead to maintain steadily in polishing area, realize the abrade polish of pair of workpiece surfaces. At the same time because suffer the effect of magnetic field force, grind bead general from assemble of tendercy polish area, assemble at be being undertaken by the surface inside polishing workpiece abrade, fashion a whole polishing loop process. 2.

2 magnetism grind a magnetic abrasive to use alumina (Al2O3) , TiC and iron pink, m; of μ of average diameter D=80 grinds the average diameter of a photograph: D1=5 μ M, d2=1.

2 μ M. Process clearance: 1.

5mm. Magnetic induction intensity: B=0.

5T. Average and abrade pressure is in 20~50 KPa. Workpiece axial shakes 20 Hz of ～ of frequency F = 0. 2mm of ～ of A= 0 of workpiece axial amplitude. 1140 R/min of workpiece rotate speed. Intensity of magnetic induction of the surface inside workpiece is 0.

3T. Magnetic pole extreme is used become sectional to design, magnetic pole and coil use DT4 electrical engineering iron, motherboard uses DT2 electrical engineering iron, the sectional area of iron of magnetic pole of magnetic flux direction, core, motherboard is 8 Cm2 respectively, 12.

5cm2, 20cm2, the cupreous enamel-insulated wire that coil uses φ 1mm2 is circled make 6000 v/LIT all over the ground, use dc power supply. Voltage of the biggest output is 25 V, output of the biggest electric current is 3A. 2.

The YG6 hard metal that 3 diamond help the preparation underlay of filar mould use city to make work presses filar standard, measurement standards 6 Mm) of φ of aperture of 30 × 21(, undertake to underlay acid is corroded above all before deposit go powder of cobaltic, diamond is abrade thick change and decarbonization is reductive wait for finishing, in order to assure the adherent force between the quality of diamond coating and underlay and coating. Coating deposit uses heater CVD method, use perforation to help heater CVD new method continuously, gain wear-resisting, adherent strength the diamond coating with strong, even coating presses filar standard. Its characteristic is a tantalum silk that crosses modular aperture heat up filament as incentive source, this heater is used high temperature resistant bedspring is pulled straight, be in the axes position of aperture of the model that pull silk, make inside the temperature of aperture surface keeps basic and even in whole and deposit process. To make up for the inadequacy of power of odd root heater, bring to bear on to shed bias voltage continuously in heater and surface of the aperture inside the model that pull silk (hot filament is negative pole, electric current of discharge of dc of generation of 50 ～ 150 V) (0.

4 ～ 2.

0A) , whole inside Kong Cheng is plasma space, the nucleate that quickened film and grow. Reaction gas is hydric with acetone, acetone chroma is 1%- 3%(Maerbi) , hot filament temperature makes an appointment with 2200 ℃ when deposit, temperature of modular aperture surface makes an appointment with 800 ℃ , deposit time 4 ～ 5 H, m of μ of coating ply 5~10. Coating pulls filar model installation to be in inside magnetism on aperture polish device undertake polishing, polishing time is 20 Min, the way of methodological edge axes that plays the diamond coating of polishing around filar model to use line cut is cut equal two half, observe polishing effect with scanning report lens next, measure surface roughness of diamond film surface with measuring instrument of Talysurf6 surface surface roughness, check filmy quality with Raman spectrum. 3.

Test result and discussion graph 2 for inside aperture diamond coating is in the exterior form appearance of around of magnetic and abrade polish, the sample after apparent polish is handled becomes relatively smooth level off, the pointed horn of the end outside grain eliminate, achieve idealer result. Surface roughness of diamond film surface by the Ra0 of craft A.

4543 μ M drops the Ra 0 of craft B.

M of 1078 μ . Nextpage 　 plan differs on the aperture inside the 3 moulds after be being handled for polishing the exterior form appearance of the diamond film that the position handles, can see from the graph diamond film is very smooth level off, grain is pliable, bright and clean degree very tall. Decide diameter belt and working awl part especially. The graph shows those who be different position 4 times to draw the sectional plan of film of diamond of the aperture inside filar model. The diamond film ply that can see from inside the graph each positions are in is very even. The graph shows the Raman chart that for the aperture inside the mould after polishing different position handles diamond film 5 times to pursue. Can see from inside the graph, inside the diamond film of aperture surface all has apparent diamond feature peak, work among them the diamond film quality that awl is in is opposite the diamond film quality at other position is better, outside the diamond feature peak that is in besides 1332cm-1, without the peak value with overt other, and still contain certain black lead peak in the belt that decide way and exit awl place, because the position of heater is too close,the likelihood is or too far, the quality that brings about diamond is not very pure. From inside the Raman chart plan that apparently different position handles after aperture polish can see, inside the diamond with apparently deposit aperture is filmy, amount of entire after polishing constitution is good, and 1332cm-1 is in peak of standard of diamond peak deviate not much, explain filmy and in-house stress is not great, OK also the adherent force that better land assures diamond is filmy. Lever of copper of coating of the diamond after using magnetic and abrade polish presses filar standard, of coating surface bright and clean degree rise further, satisfied cupreous lever to pull silk bright and clean to surface of the aperture inside the mould spent higher demand. The working life that coating plays filar model raises 8 ～ than hard alloy 10 times, individual mould crop can amount to 3000 T, apparent excel hard alloy helps the quality that pull silk filar model. 4.

Conclusion uses face of coating of diamond of magnetic and abrade polish, the pointed part that can carry outside effective eliminate grain, and the loss that won't cause coating, do not affect coating to add exert oneself, can achieve idealer result, because the surface is rough,break through groovy diamond film thereby, polishing difficulty is big, right the bottleneck that coating drawing mould cannot satisfy actual application to need, have important sense to the industrialization of technology of CVD diamond coating. CNC Milling