The research that copper manages in polisher of the chemistry in fluid of polish of low nitric acid

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Copper manages to have not see a story up to now in the chemical polisher in nitric acid system. For this, our choice is vitriolic - nitric acid - hydrochloric acid - water system regards research as the object, earnings result is comfortable also child the polish of 3 acerbity chemistry of the 3 acerbity chemical polish of tall nitric acid and low nitric acid. Research technique is consumed reflectivity respectively the law determines the brightness of cupreous surface, determine with weight law of polishing around test piece corrode weightlessness, with Hitachi × lens of 650 scanning report determines the exterior form appearance when different polish process; With parameter of the M270 of EG&G company electrochemistry integrated instrument determines the potential in polishing process - time-speed-distance curve and electric current - potential curve, the result that determines integratedly finally, put forward the mechanism of polish of red copper chemistry. One, the reflection when the polish below chroma of different nitric acid leads copper - 2-13 of time-speed-distance curve graph is in for copper when the 3 acid of different chroma nitric acid undertake chemical polish in mixed liquor, exterior reflection leads the metabolic curve that lets time. See by graph 2-13, the exterior brightness of polishing print produces change along with chroma of the HNO3 in polishing time and polishing fluid, and the curve all has same figure. It is above all as chemical polish process undertake, exterior brightness drops quickly, exterior happening corrodes right now print, call erode level; Subsequently, exterior brightness rises gradually again, corrode nick to disappear gradually again, enter shining phase namely. When shining phases ends, reflection rate amounts to highest value; Continue to extend polishing time, the hemp hole that shining surface had appeared to corrode (dot corrode) , and hemp hole amount is added gradually much, exterior brightness drops, polishing process has been entered corrode level. See not hard still by graph 2-13, join of the HNO3 in polishing fluid ceaselessly, shortened the limits that level and shining phase erode in polishing process, had accelerated those who corrode level to appear. HNO3 density is too low, although shining phase range is big, dan Guangliang is spent not tall; HNO3 chroma is exorbitant, criterion the surface is easy had happened to corrode. HNO3 concentration control is in 80mL/L~100mL/L, can gain the red copper face of tall brightness. 2, copper issues the weightlessness when polishing in chroma of different nitric acid - time-speed-distance curve uses weightlessness law to determine deliquescent in the polishing fluid of different chroma HNO3 quantity follows red copper the change of time. Its are shown as a result at graph 2-14. See by graph 2-14, the weightlessness of different chroma HNO3 - time-speed-distance curve follows same pattern, namely in the begining, the weightlessness of red copper increases quickly along with polishing time, subsequently gradually gently rise, increase quickly finally again. This change trend is corresponding at polishing by erode the level, process that corrupts level through arriving shining phase, finally. Increase as pH indicator of bogus of the HN in polishing fluid, the deliquescent rate of red copper increases gradually, HN field content is exorbitant, range of shining phase is too narrow, the gently area of corresponding weightlessness curve is not apparent already. 3, copper scans in the surface of the different level of chemical polish the scanning report lens that 2-15 of graph of electric lens analysis is red copper to handle different time in polishing fluid analyses a scheme. See by graph 2-15, the print of 10s is handled in polishing fluid, whole face all happened to corrode (2-15(a)) seeing a picture; After polishing 50s, of print surface corrode a trace to disappear, the acting appearance with level off and brightness (2-15(b)) seeing a picture; Continue to extend polishing time to 90s, shining print surface produces inhomogenous pitting attack again (2-15(c) seeing a picture) . Accordingly, the observation of the appearance of cupreous surface form of different time is handled in polishing fluid through be opposite, proved polishing process experienced 3 level further, they are ordinal to erode, brightness and corrode level too, the procedure of this and electropolishing is completely similar. Nextpage4, copper plays the potential when polishing in chroma of different nitric acid - the potential of the copper in the chemical polish fluid of nitric acid of different to immerge chroma undertakes time-speed-distance curve determine continuously, its are shown as a result at graph 2-16. See by graph 2-16, potential of pH indicator of different nitric acid for a short while metabolic trend of the curve is identical. Namely polishing process in the begining, potential drops quickly along with time (negative move) , subsequently potential gradually slow rise (moving) to stable value. This as it happens is corresponding 3 phase at chemical polish process. Additional, as content of the nitric acid in polishing fluid increase, cupreous potential also is moving gradually, the metabolic curve that the aluminium that this result and Arrowsmith and Cunningham determine lets time in the potential in polishing process is identical. 5, copper issues the electric current when polishing in chroma of different nitric acid - potential graph 2-17 is the electric current when copper is handled in the chemical polish fluid in different chroma nitric acid - potential curve. We discover, the zincous polarization curve of the appearance of the curve in the graph and electropolishing process is very similar, they all divide composition by 3 features ministry: The first part of the curve is electric current moving and rise quickly what follow potential, this correspondence is mixed at the activation condition of metallic surface active and deliquescent process of the metal, namely of polishing process erode level; The 2nd part of the curve, the change that electric current follows potential is very little, namely of polarization curve of the positive pole in electropolishing process " even area " , show right now the metal is passivation condition from activation status change, the shining phase of this corresponding polish process; The 3rd part of the curve is located in potential to pass area, right now passivation condition of the metal is broken again, the metal is corroded further, had entered namely corrode level. 6, copper is in nitric acid - vitriolic - the mechanism of chemical polish in hydrochloric acid system is led by scanning report lens, reflection - time-speed-distance curve and weightlessness - of time-speed-distance curve and electrochemistry determine result, we know chemical polish process can be divided to erode, brightness and corrode 3 phase too. Electric current - potential curve makes clear to existing likewise in chemical polish process of electropolishing " even area " . Passivation film theory ever was used those who explain electropolishing process is medium by people " even area " . The existence of film of passivation of surface of the metal in chemical polish process also has many stories. Hickling studied iron the chemical polish in H2O2-H2SO4 fluid, those who think the gas with periodic surface of the metal in chemical polish process produces apparently as paper-thin as iron oxide is ceaseless generate and dissolve about. Vengris use negative pole reductive law and electronic diffraction law determined the composition of the exterior passivation film that when copper reachs alloy to fasten the processing in polishing fluid in H2O2, forms and ply. Accordingly, we have reason to think the passivation film theory of electropolishing process applies to chemical polish as much. In chemical polish process erode level, the metal is in activation condition, because metallic face is different position office electrochemistry and physico-chemical property are different, make metal apparently existing the share with a lot of different potential, form instantaneous quickly to close consequently galvanic cell, generation corrosion current, and corrosion current is chased increase gradually, those who cause metallic appearance is inhomogenous deliquescent, corresponding and zincous electric current follows potential and metallic weightlessness to increase quickly along with time, produce cankerous exterior construction thereby. Achieve when corrosion current quite tall when, be in likely metal apparently form passivation film, corresponding metal is passivation condition by activation status change, electric current - the even area in potential curve appears, metallic weightlessness also tends gently, right now of the metal erode the surface to be replaced by shining surface place gradually, enter shining phase namely. Of the because metallic ion and metallic surface are raised electrolyte is medium ion near place diffuse sunkener cereal part has the process older rate, the passivation level that causes protruding sunken share is different, raisedder place is in sunken cereal place more stable passivation condition, active of raised place chemistry is big, of the oxidation film on its deliquescent relatively rapid, cause metallic appearance thereby of raised place preferential and deliquescent, achieve the goal of shining level off thereby. Lengthen of time further as polishing, passivation condition of the metal is broken, electric current increases quickly again along with the weightlessness rate of potential and metal, metallic surface has had correspondence to corrode hemp hole. The place on put together is narrated, we can reach the following conclusion: (1) the exterior brightness in chemical polish process, weightlessness and potential follow red copper the test of the metabolic curve of time and scanning report lens makes clear as a result, chemical polish process has been mixed by dip corrode, brightness corrode 3 phase composition. (2) electric current - potential curve makes clear, about the passivation film theory of electropolishing, apply to chemical polish likewise. CNC Milling