The research of technology of passivation of silicate of galvanization armor plate makes progress

In the progress of passivation of foreword 　 silicate, choose a kind or all sorts of performance that a variety of organic matter silicon help inorganic silicate raise passivation film will be the important way that will study henceforth. According to studying earning: It is easy that the low, craft that make compares the fee that chromate passivation place uses. Silicate passivation is the passivation technology of a kind of avirulent, free from contamination, although craft still does not consider the special maturity, efficiency that become film not tall [1] . But this one problem is being solved below our effort is inevitable. 1.

Silicate passivation craft and flow 　 1.

Li Anchao of craft of 1 silicate passivation uses what saline mist experiment checks film of galvanization layer passivation to be able to bear or endure corrode sex, studied the craft condition of passivation of galvanization layer silicate, optimal craft is in PH3.

0, the passivation craft condition of 90s of time of 30 ℃ , passivation issues temperature, group of silicate passivation fluid becomes siliceous natrium 40g/L, 98% vitriolic 4ml/L, 30% when crossing 2ml/L of 2ml/L of 7g/L of Niao of oxidation hydrogen 40ml/L, sulfur, 67% nitric acid, 85% phosphoric acid. 1.

The characteristic of passivation of silicate of 2 galvanization armor plate passes Li Anchao's experiment to make clear: The corrosion resistance that galvanization layer can increase board effectively can, it is its more just corroded. Now nowadays, chromate passivation has received wide application, no matter still have its from velar layer intensity or craft respect,other places face had obtained certain research positive result, have definite advantage. But, it is virulent and easy that chromium of the 6 prices in chromate is had cause a disease [2] , accordingly, chromate passivation technology has faced enormous challenge. Silicate handles cost cheap, stability is good, use simple, avirulent wait for an advantage. Basically contain in silicate passivation fluid vitriolic, cross oxidation hydrogen and solubility silicate, [3] . Normally the circumstance falls, to enhance all sorts of performance of film, add so organic facilitating agent, undertake an aftertreatment likely still to passivation film. 2.

Galvanization armor plate corrodes passivation mechanism 　 without chromium 2.

Silicate of mechanism of 1 silicate passivation has passivation cost film of low, passivation corrosion resistance passivation fluid stability is good, good, use the good point such as convenient, avirulent, free from contamination. (1) galvanization in relief polar region produces reaction: ZN, Zn2++2e one. (2) area of corrosion cell small cathode: 2H++2e- , H2 or (O2+2H20+4e, 40Kr. (3) the reaction that the cathode area of film surface produces, make zincic layer surface local acid-base value increases, not easy dissolve is formed in zincic layer surface the compound at water. (4) in passivation process, passivation fluid system shows acidity, rate of response of acerbity dehydrate condensation polymerization also is added fast, generate petty colloid space of fill of 2 oxidation silicon is adsorptive at velar layer surface. 2.

Of 2 galvanization and its galvanization layer corrode mechanism to be able to bear or endure corrode mechanism considers to make clear, film of passivation of the silicate in corrupting a process is to pass segregation and electrochemistry slow corrode action to be opposite thereby plating undertake protective. Make his corrosion resistance increases. 3.

　 of silicate passivation influencing factor 3.

The influence basis of 1 passivation time document account: Salt of passivation time neutral does not have mist experiment (the change of 24h[14] of NSS) successive sparge as passivation time by 205 arrive 605 between corrode an area by 40% drop 2% , because this is inside this paragraph of time of the growth passivation film as passivation time be able to bear or endure corrode sex is in increase " gradually but in 605 later corrode an area to increase gradually, arrive 1005 when for 75% , explain time jumps over long word, be able to bear or endure the process becoming film that corrode sex is that is to say with respect to can poorer " between one 605s of 205s is whole passivation film, be in 605 when the character that become film is best, make clear in galvanization layer formed an even diaphragm, increased corrosion resistance thereby. 3.

The influence that 2PH is worth corrodes an experiment according to oxidation film knowable: Be worth as PH by 0.

5 to 2.

The change of 5, of passivation film corrode an area from 75% drop 3% , be able to bear or endure to corrupt sex increases " and be worth when PH so by 2.

5 to 4.

5 when corrode an area from 3% to 95% , be able to bear or endure corrode sex is worse and worse, when PH the value is more than 4.

5 Shi Dun changes film to form occurrence issue, PH value is a when passivation becomes film important data, great to the influence of passivation film, PH cost is too low, have to galvanization layer bigger corrode do with, formation passivation film is worse, so anti-corrosive poorer, but PH value is exorbitant, can make passivation fluid not stable, can generate Zn, form passivation film not easily. 3.

The influence of 3 passivation temperature is opposite according to passivation temperature the experiment of oxidation film is knowable; is become passivation temperature from 25 increase gradually to 55 when, of passivation film corrode an area from 5% increase 98% , be able to bear or endure corrode sex drops speed accelerates " to come when thermal drop 15 when, corroded an area to also increase " to be able to see passivation temperature has very big effect to passivation from this, film of temperature low passivation is thin, into film bad, temperature is too high passivation film is deliquescent accelerate, quicken those who cross H2O2 to decompose, make the " of stability worse and worse of passivation fluid temperature is too so high too low perhaps all meet those who affect passivation film be able to bear or endure corrode sex, must control reaction temperature rigorously so. 3.

4 silicate chroma affects the content of silicate to increase 50g/L from 10g/L, of passivation film corrode an area from 50% fall 5% , increase 60%" to pass this experiment to be able to see when silicate content is in apparently again next corrode sex is able to bear or endure when 20g/L is controlled best " . 4.

Study the current situation carries the research of the article, research and development gave a kind not to have chromic, environmental protection model the silicate passivation craft of galvanization will substitute technology of traditional chromate passivation, from the foundation improvement eletroplates the harm that pollutes pair of mankind bodies and nature environment. The technology of passivation of the silicon acid that do not have chromium that article place researchs had obtained certain research to make progress, to its film of condition of passivation fluid composition, craft, passivation formed mechanism and stability respect to do certain and simple research. Be in so future, foreground of passivation of the silicate that do not have chromium auspicious. CNC Milling CNC Machining