1、Designation: D 6280 98 (Reapproved 2008)Standard Specification forZinc Phosphate Pigments1This standard is issued under the fixed designation D 6280; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers three types of pigments com-mercially known as zinc phosphate each of which may or maynot be available in specifi
3、c grades delineated by particle size oroil absorption.1.1.1 Type IZinc Phosphate, dihydrate predominant.1.1.2 Type IIZinc Phosphate, dihydrate tetrahydrate mix-ture.1.1.3 Type IIIZinc Phosphate, tetrahydrate predominant.1.2 The values stated in SI units are to be regarded asstandard. No other units
4、of measurement are included in thisstandard.2. Referenced Documents2.1 ASTM Standards:2D 153 Test Methods for Specific Gravity of PigmentsD 185 Test Methods for Coarse Particles in PigmentsD 280 Test Methods for Hygroscopic Moisture (and OtherMatter Volatile Under the Test Conditions) in PigmentsD 2
5、81 Test Method for Oil Absorption of Pigments bySpatula Rub-outD 1193 Specification for Reagent WaterD 1208 Test Methods for Common Properties of CertainPigmentsD 1210 Test Method for Fineness of Dispersion of Pigment-Vehicle Systems by Hegman-Type GageD 2448 Test Method for Water-Soluble Salts in P
6、igments byMeasuring the Specific Resistance of the Leachate of thePigment3. Significance and Use3.1 Zinc phosphate functions as both a chemical and apigment. As a pigment it is used in a variety of applicationsincluding that of corrosion inhibiting paints.4. Composition and Properties4.1 Zinc phosph
7、ate pigment is a white corrosion inhibitingpigment consisting either predominately of zinc phosphatedihydrate (Zn3(PO4)22H2O) or a mixture of zinc phosphatedihydrate and zinc phosphate tetrahydrate (Zn3(PO4)24H2O)or predominately of zinc phosphate tetrahydrate which is freefrom extenders, diluents,
8、and other pigments.4.2 Zinc phosphate shall be a chemically prepared pigmentand shall be of such type and grade as to conform to therequirements prescribed in Table 1. They shall additionally befree of extenders, modifiers, diluents, alteration of stoichiomet-ric chemical structure, co-reacted preci
9、pitates, and carbon-aceous material.4.3 The desired properties of the pigment, other than asherein indicated, shall be subject to mutual agreement betweeninterested parties and shall be based upon a satisfactory matchbetween any submitted sample and a previously agreed uponreference sample.5. Classi
10、fication5.1 Type Iwhich consists predominately of zinc phosphatedihydrate (Zn3(PO4)22H2O) and exhibits a differentiating losson ignition of the dried pigment at 600C between 8.5 and 10.0weight %.5.2 Type IIwhich consists essentially of a mixture of zincphosphate dihydrate (Zn3(PO4)22H2O) and Zinc Ph
11、osphateTetrahydrate (Zn3(PO4)24H2O) and exhibits a differentiatingloss on ignition of the dried pigment at 600C between 10.0and 14.0 weight %.5.3 Type IIIwhich consists predominately of zinc phos-phate tetrahydrate (Zn3(PO4)24H2O) and exhibits a differenti-ating loss on ignition of the dried pigment
12、 at 600C between14.0 and 18.0 weight %.6. Sampling6.1 Two samples shall be taken at random from differentpackages from each lot, batch, days pack or other unit ofproduction in a shipment. When no markings distinguishingbetween units of production appear, samples shall be takenfrom different packages
13、 in ratio of two samples for each 5000kg, except for those shipments of less than 5000 kg where twosamples shall be taken. At the option of the interested party the1This specification is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the
14、 direct responsibility ofSubcommittee D01.31 on Pigment Specifications.Current edition approved Nov. 1, 2008. Published November 2008. Originallyapproved in 1998. Last previous edition approved in 2003 as D 6280 98 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontac
15、t ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.samples may be tested se
16、parately or as a composite sampleformed by blending in equal quantities the samples from thesame unit of production.7. Test Methods7.1 Tests shall be conducted in accordance with the follow-ing test methods. Test procedures not incorporated here and notcovered by ASTM test methods shall be mutually
17、agreed uponbetween the interested parties.7.1.1 Specific GravityTest Methods D 153, Method B.7.1.2 Oil AbsorptionTest Method D 281.7.1.3 Hegman GrindTest Method D 1210.7.1.4 Coarse ParticlesTest Methods D 185.7.1.5 pHTest Methods D 1208.7.1.6 Specific ResistanceTest Method D 2448.7.1.7 MoistureTest
18、Methods D 280.7.1.8 Chemical AnalysisIncorporated in this specificationas Annex A1 and Annex A2.7.1.9 Loss on IgnitionIncorporated in this specification asAnnex A3.8. Keywords8.1 analytical; zinc; zinc phosphateANNEXES(Mandatory Information)A1. TEST METHOD FOR DETERMINATION OF ZINC CONTENT FOR ZINC
19、PHOSPHATE TYPE PIGMENTSA1.1 ScopeA1.1.1 This test method covers the determination of thezinc content for zinc phosphate monohydrate, dihydrate, tet-rahydrate, or mixtures of these various crystal water contentpigments.A1.1.2 This standard does not purport to address all thesafety concerns, if any, a
20、ssociated with its use. It is theresponsibility of whoever uses this standard to consult andestablish the appropriate safety and health practices anddetermine the applicability of regulatory limitations prior touse.A1.2 Reference DocumentsA1.2.1 ASTM Standards:Test Method for Determination of Loss o
21、n Ignition for ZincPhosphate Type PigmentsTABLE 1 Zinc Phosphate Pigment PropertiesProperty TYPE I TYPE II TYPE IIIZnO, weight percent 62.6 - 65.1 62.6 - 65.1 62.6 - 65.1(on ignited sample)P2O5, weight percent 34.9 - 37.4 34.9 - 37.4 34.9 - 37.4(on ignited sample)Loss on ignition, weight 8.5 - 10.0
22、10.0 - 14.0 14.0 - 18.0percent (of dried pigment)GRADE GRADE GRADEMean Particle Size F M C F M C F M C(microns) 5.0 same sameOil adsorption 30 30 - 15 15 same sameMatter soluble in water, 6500 6500 6500specific resistance,(min. ohm - cm)Moisture and other volatile 0.5 0.5 0.5matter (105 - 110C)Speci
23、fic gravity, g/cm33.0 - 3.5 3.0 - 3.5 3.0 - 3.5Hegman grind 6 min 6 min 6 minCoarse particlepercent residue 325 M (45m)0.5 max 0.5 max 0.5 maxpH, aqueous suspension 6 - 8 6 - 8 6 - 8D 6280 98 (2008)2D 1193 Specification for Reagent WaterA1.3 Summary of Test MethodA1.3.1 A weighed sample taken from A
24、nnex A3, TestMethod for Determination of Loss on Ignition for ZincPhosphate Type Pigments completed analysis (that is, samplecontains no associated crystal water), is dissolved in ammoniabuffer, complexed with disodium ethylendiaminetetraacetatedihydrate (EDTA) and back titrated with a standard zinc
25、solution to an eriochrome black T endpoint where the percentZnO is determined.A1.4 Significance and UseA1.4.1 This test method provides a reliable means fordetermination of the percent ZnO for zinc phosphate pigments.The percent ZnO content for the product gives evidence of thechemical purity of the
26、 pigment.A1.5 Reagents and MaterialsA1.5.1 Purity of ReagentsReagent grade chemicals shallbe used in this test, unless otherwise indicated. It is intendedthat all reagents shall conform to the specifications of theCommittee on Analytical Reagents of the American ChemicalSociety, where such specifica
27、tions are available. Other gradesmay be used, provided it is first ascertained that the reagent isof sufficiently high purity to permit its use, without lesseningthe accuracy of the determination.A1.5.2 Purity of WaterUnless otherwise indicated, refer-ences to water shall be understood to mean Type
28、II ofSpecification D 1193.A1.5.3 Buffer Solution (pH 10)350 ml of concentratedNH4OH+NH4Cl and H2O to give 1000 mL.A1.5.4 Eriochrome Black T Indicator (0.5 %)0.25 g erio-chrome Black T + 2.2 g hydroxylamine hydrochloride per 50mL methanol.A1.5.5 Primary Standard Zinc Oxide (0.2 N solution)Accurately
29、weigh 4.0690 g of oven dried ZnO. Dissolve in 250mL of the buffer solution and dilute to 500 mL. (Conversely,you can weigh up approximately 4.0 g of ZnO, create thesolution, and standardize it using the primary standard gradeZnO.)A1.5.6 0.2 N Disodium Ethylendiaminetetraacetate Dihy-drate (EDTA)37.2
30、 g of EDTA per litre of aqueous solution.A1.6 ProcedureA1.6.1 Weigh approximately 0.25 g (see Annex A3)induplicate to the nearest 0.1 mg. Place in respective Erlenmeyerflasks. Add 25 mL of the pH 10 buffer solution. Stir gently todissolve. Pipet 50.00 mL of the EDTA solution into eachrespective Erle
31、nmeyer flask. Dilute to 200 mL with dionizedwater.Add 6 to 7 drops of eriochrome Black T indicator. Titratewith the 0.2 N ZnO solution to a wine - red endpoint. Run ablank by titrating 50.00 mL EDTA containing 25 mL of pH 10buffer solution with the 0.2 N ZnO solution.A1.7 CalculationsA1.7.1 Calculat
32、e the percent ZnO as follows:% ZnO 5VbVs! 3 N ZnO 3 4.069Mass of Sample(A1.1)where:Vb= ZnO for blank, mL,Vs= ZnO for sample, mL,N = normality of the zinc solution, and4.069 = factor for conversion to % ZnO.A1.7.2 Report the mean, estimated standard deviation, andcoefficient of variation for the anal
33、ysis.A1.8 Precision and BiasA1.8.1 PrecisionResults should be considered suspect ifthe standard deviation is greater than 0.2 %.A1.8.2 In an repeatability study of this test method, inwhich two samples containing 50.5 to 52.0 % ZnO wereanalyzed by one operator per test, the observed standarddeviatio
34、n for 100 separate tests was determined to be 0.066.A1.8.3 BiasBias does not apply because there is nomaterial of acceptance value available.A2. TEST METHOD FOR DETERMINATION OF PHOSPHATE CONTENT FOR ZINC PHOSPHATE TYPE PIGMENTSA2.1 ScopeA2.1.1 This test method covers the determination of thephospha
35、te content for zinc phosphate monohydrate, dihydrate,tetrahydrate, or mixtures of these various crystal water contentpigments.A2.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish
36、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.A2.2 Reference DocumentsA2.2.1 ASTM Standards:Test Method for Determination of Loss on Ignition for ZincPhosphate Type PigmentsD 1193 Specification for Reagent WaterA2.3 Summary of Test
37、MethodA2.3.1 A weighed sample taken from Annex A3, TestMethod for Determination of Loss on Ignition for ZincPhosphate Type Pigments completed analysis (that is, samplecontains no associated crystal water), is dissolved in ammonia,and the liberated phosphate precipitated with ammoniummolybdate. The r
38、esulting precipitate is filtered through aGooch or sintered glass crucible and dried to constant weightwhere the percent P2O5is determined.A2.4 Significance and UseA2.4.1 This test method provides a reliable means fordetermination of the percent P2O5for zinc phosphate pigments.D 6280 98 (2008)3The p
39、ercent P2O5content for the product gives evidence of thechemical purity of the pigment.A2.5 ApparatusA2.5.1 Analytical Balance, capable of weighing to thenearest 0.1 mg.A2.5.2 Oven, capable of maintaining a temperature of 105Cfor2horlonger.A2.5.3 Gooch or medium porosity sintered glass crucibles.A2.
40、5.4 Spatula Tongs.A2.5.5 Desiccator, with drying agent.A2.6 Reagents and MaterialsA2.6.1 Purity of ReagentsReagent grade chemicals shallbe used in this test, unless otherwise indicated. It is intendedthat all reagents shall conform to the specifications of theCommittee on Analytical Reagents of the
41、American ChemicalSociety, where such specifications are available. Other gradesmay be used, provided it is first ascertained that the reagent isof sufficiently high purity to permit its use, without lesseningthe accuracy of the determination.A2.6.2 Purity of WaterUnless otherwise indicated, refer-en
42、ces to water shall be understood to mean Type II ofSpecification D 1193.A2.6.3 Concentrated Ammonium Hydroxide,NH4OH.A2.6.4 Concentrated Nitric Acid, HNO3.A2.6.5 Ammonium Nitrate,NH4NO3.A2.6.6 Ammonium Molybdate (Johnsons Formula) : Mix55gof(NH4)6Mo7O244H2Oand50gofNH4NO3with 18 mLof NH4OH and 20 mL
43、of H2O. Stir. Dilute to 700 mL withH2O, and heat with occasional stirring until all salts havedissolved. Dilute to 1000 mL. Let stand overnight. Filter thesolution using a fine grade filter paper but do not wash theresidue.A2.7 ProcedureA2.7.1 Weigh approximately 2.0 g (see Annex A3)ofthetest pigmen
44、t in duplicate to the nearest 0.1 mg. Place in a250-mL glass stoppered Erlenmeyer flask. Add 25 mL ofNH4OH, stopper, and swirl over a period of 60 min. Add 25mL of H2O and filter through fine filter paper into a 400-mLbeaker, washing the residue well with water. Neutralize thefiltrate with HNO3(requ
45、ires approximately 35 mL). Add 15mL of HNO3and6gofNH4NO3. Stir. Heat the clear solutionto 80 C (do not exceed) and add 75 mL of the ammoniummolybdate solution with constant stirring. Stir for severalminutes and let the precipitate settle for a minimum of 2 h.Filter the precipitate through a tared go
46、och or medium glasscrucible. Wash the precipitate well with 1 % HNO3, then givea final wash with water. Dry the crucible and its contents for 2h at 105 C in an oven. Cool the crucible in a desiccator anddetermine the weight of the precipitate to the nearest 0.1 mg.A2.8 CalculationsA2.8.1 Calculate t
47、he percent P2O5as follows:%P2O55mass PPT 3 3.783mass sample(A2.1)A2.8.2 Report the mean, estimated standard deviation, andcoefficient of variation for the analysis.A2.9 Precision and BiasA2.9.1 PrecisionResults should be considered suspect ifthe standard deviation is greater than 0.2 %.A2.9.2 BiasSe
48、e previous statement given in A1.8.3.A3. TEST METHOD FOR DETERMINATION OF LOSS OF IGNITION OF ZINC PHOSPHATE TYPE PIGMENTSA3.1 ScopeA3.1.1 This test method covers the determination of the losson ignition in zinc phosphate monohydrate, dihydrate, tetrahy-drate, or mixtures of these various crystal wa
49、ter contentpigments.A3.2 Summary of Test MethodA3.2.1 A sample of zinc phosphate is dried at 110C for 1 hto constant weight.A3.2.2 A weighed portion of the previously dried zincphosphate with associated crystal water is ignited in a muffleoven at 600C for 30 min and the crystal water amount isdetermined by difference.A3.3 Significance and UseA3.3.1 This test method provides a reliable means fordetermining the associated crystal water content on zincphosphate pigments, and its respective classification type.A3.4 ApparatusA3.4.1 Analyti
