CN104789956A - Black trivalent chromium passivation agent with high corrosion resistance - Google Patents

Abstract

The invention discloses a preparation method for a black trivalent chromium passivation agent with high corrosion resistance. The passivation agent is prepared by mixing a solution A, a solution B and deionized water according to the fact that the volume ratio of the solution A to the solution B to the deionized water is 8:3:89, wherein each liter of the solution A is prepared by mixing and dissolving 200-250 g of chromic nitrate, 100-150 g of cobalt nitrate and the balance of deionized water; each liter of the solution B is prepared by mixing and dissolving 80-120 g of citric acid or malonic acid, 5-50 g of sodium hydrogen sulfite, 45-250 g of an ammonium thioglycolate water solution with the concentration of 50%, 20-200 g of thiodiglycolic acid and the balance of deionized water.

Description

High anti-corrosion trivalent chromium black passivator

Technical field

The open a kind of high anti-corrosion trivalent chromium black passivator of the present invention, relates to passivator preparation field.

Background technology

In recent years, along with the development that production is advanced by leaps and bounds, also more and more higher to zinc-plated requirement, particularly European Union endorsed a decree in 2003 in Brussels, regulation forbade using sexavalent chrome in vehicle material and parts from 1 day January in 2003, according to this decree, the content of 6-valence Cr ions of each automobile is no more than 2 grams.On August 14th, 2004, European Union's " electronic waste facture " formally puts into effect, and on August 13rd, 2005, this regulation formally comes into effect.This decree is that two instructions of foundation European Union in 2002 complete; These two instructions are " about scrapping electronic and electrical equipment instruction " (WEEE) and " about prohibitting the use some Hazardous Substances Directive in electronic and electrical equipment " (ROHS) respectively, require that member states guarantees from 1 day July in 2006, the new electronics and the electrical equipment that are invested in market do not comprise lead, cadmium, mercury, sexavalent chrome, poly-6 kinds of objectionable impuritiess such as dibromodiphenyl ether and poly-bromo biphenyl; The enterprise of domestic product exported product must stop using sexavalent chrome passivation technology after 13 days Augusts in 2004, popularize the agent of environment-friendlytrivalent trivalent chromium passivating in an all-round way, because domestic trivalent chromium passivator adopts ferrous sulfate (FeSO4.7H2O) and sodium hypophosphite (NaH2PO2.H2O) mostly, so the passive film in zinc layers is commonly tertiary iron phosphate, there is solidity to corrosion difference, passivator easily decomposes, and life cycle is short, outward appearance is not shiny black, the shortcoming that black is uneven.

Summary of the invention

The object of this invention is to provide a kind of high anti-corrosion trivalent chromium black passivator, use the passivator that this preparation method obtains, can good in zinc layers surface formation solidity to corrosion, outward appearance is shiny black, the passive film of black even.

Technical scheme of the present invention is as follows: the preparation method of high anti-corrosion trivalent chromium black passivator, it is characterized in that being made up of following preparation process:

1) prepare solution A: to rise, the deionized water of the chromium nitrate of 200 ~ 250g, the Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES of 100 ~ 150g and surplus continuously stirring under the condition of 60 DEG C is dissolved, obtains solution A;

2) B solution is prepared: to rise, appropriate deionized water is added in measuring cup, first add citric acid or the propanedioic acid of 80 ~ 120g, stirring and dissolving, then the sodium bisulfite adding 5 ~ 50g, after stirring and dissolving, add the thiodiglycolic acid of 20 ~ 200g again, after stirring and dissolving, then to add 45 ~ 250g concentration be the Thiovanic acid aqueous ammonium of 50% and the deionized water of surplus, stirring and dissolving, obtains B solution;

3) preparation work liquid: the deionized water and stirring of the solution A of 8L, the B solution of 3L and 89L mixed, obtains the finished product of passivator.

Advantage of the present invention is:

Solidity to corrosion is good: zinc layers is after Passivation Treatment, Surface Creation is containing the sulfide of cobalt, and solidity to corrosion is better than tertiary iron phosphate, proves through test, the passive film that this technology passivator generates in zinc layers under neutral salt spray test 120 little interior time without white rust, because passivator is not containing divalent iron ion (Fe ²⁺), institute's life cycle is long, without white rust in 72 hours that are better than tertiary iron phosphate;

Outward appearance is shiny black, black even: replace traditional iron ion blackening agent for surface, so the outward appearance of passive film is shiny black, black even owing to adopting the compound of sodium bisulfite, thiodiglycolic acid and Thiovanic acid ammonium solution.

Not containing toxic substances such as sexavalent chromes in passivator, described chromium nitrate can provide Cr ³⁺ion, therefore achieves passivator cleaner production, is convenient to wastewater treatment; Through testing proof for several times, the passivator working fluid passivation effect that the solution A prepared, B solution obtain after mixing with the volumetric ratio of 8:3:89 with deionized water is best.

Embodiment

Embodiment one: the preparation method of high anti-corrosion trivalent chromium black passivator, in often liter, get the first measuring cup, add appropriate deionized water, heat to 60 DEG C, keep constant temperature, under continuously stirring, the Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES continuously stirring of the chromium nitrate and 100g that add 200g is dissolved, and adds deionized water adjustment liquid level to 1L place, stir, obtain solution A; In often liter, get the second measuring cup, at ambient temperature, add appropriate deionized water, then add the citric acid of 80g, after being stirred to dissolving, add the sodium bisulfite of 5g again, after stirring and dissolving, then add the thiodiglycolic acid of 20g, after stirring and dissolving, the concentration adding 45g is again after the Thiovanic acid aqueous ammonium stirring and dissolving of 50%, the deionized water adding surplus, to the 1L place of measuring cup, is continuously stirring to dissolving, obtains B solution; As stated above, the B solution of the preparation solution A of 8L and 3L is stand-by, in use, use stirred vessel, at ambient temperature, in container, add the deionized water of 89L, under continuously stirring, add the solution A of 8L and the B solution of 3L, be uniformly mixed the finished product of rear acquisition passivator working fluid.

Embodiment two: the preparation method of high anti-corrosion trivalent chromium black passivator, in often liter, get the first measuring cup, add appropriate deionized water, heat to 60 DEG C, keep constant temperature, under continuously stirring, the Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES continuously stirring of the chromium nitrate and 150g that add 250g is dissolved, and adds deionized water adjustment liquid level to 1L place, stir, obtain solution A; In often liter, get the second measuring cup, at ambient temperature, add appropriate deionized water, then add the propanedioic acid of 120g, after being stirred to dissolving, add the sodium bisulfite of 50g again, after stirring and dissolving, then add the thiodiglycolic acid of 200g, after stirring and dissolving, the concentration adding 250g is again after the Thiovanic acid aqueous ammonium stirring and dissolving of 50%, the deionized water adding surplus, to the 1L place of measuring cup, is continuously stirring to dissolving, obtains B solution; As stated above, the B solution of the preparation solution A of 8L and 3L is stand-by, in use, use stirred vessel, at ambient temperature, in container, add the deionized water of 89L, under continuously stirring, add the solution A of 8L and the B solution of 3L, be uniformly mixed the finished product of rear acquisition passivator working fluid.

Embodiment three: the preparation method of high anti-corrosion trivalent chromium black passivator, in often liter, get the first measuring cup, add appropriate deionized water, heat to 60 DEG C, keep constant temperature, under continuously stirring, the Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES continuously stirring of the chromium nitrate and 125g that add 225g is dissolved, and adds deionized water adjustment liquid level to 1L place, stir, obtain solution A; In often liter, get the second measuring cup, at ambient temperature, add appropriate deionized water, then add the propanedioic acid of 100g, after being stirred to dissolving, add the sodium bisulfite of 27.5g again, after stirring and dissolving, then add the thiodiglycolic acid of 110g, after stirring and dissolving, the concentration adding 147.5g is again after the Thiovanic acid aqueous ammonium stirring and dissolving of 50%, the deionized water adding surplus, to the 1L place of measuring cup, is continuously stirring to dissolving, obtains B solution; As stated above, the B solution of the preparation solution A of 8L and 3L is stand-by, in use, use stirred vessel, at ambient temperature, in container, add the deionized water of 89L, under continuously stirring, add the solution A of 8L and the B solution of 3L, be uniformly mixed the finished product of rear acquisition passivator working fluid.

The passivator finished product that above embodiment obtains in use, is undertaken by the operation of conventional passivation agent working fluid; Store solution A and B solution respectively during storage, carry out being hybridly prepared into passivator working fluid with deionized water again during use.

Claims (1)

1. the preparation method of high anti-corrosion trivalent chromium black passivator, is characterized in that being made up of following preparation process:

1) prepare solution A: to rise, the deionized water of the chromium nitrate of 200 ~ 250g, the Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES of 100 ~ 150g and surplus continuously stirring under the condition of 60 DEG C is dissolved, obtains solution A;

2) B solution is prepared: to rise, appropriate deionized water is added in measuring cup, first add citric acid or the propanedioic acid of 80 ~ 120g, stirring and dissolving, then the sodium bisulfite adding 5 ~ 50g, after stirring and dissolving, add the thiodiglycolic acid of 20 ~ 200g again, after stirring and dissolving, then to add 45 ~ 250g concentration be the Thiovanic acid aqueous ammonium of 50% and the deionized water of surplus, stirring and dissolving, obtains B solution;

3) preparation work liquid: the deionized water and stirring of the solution A of 8L, the B solution of 3L and 89L mixed, obtains the finished product of passivator.