1、BRITISH STANDARD BS EN ISO 9455-3:1995 Soft soldering fluxes Test methods Part 3: Determination of acid value, potentiometric and visual titration methods The European StandardENISO9455-3:1994 has the status of a British Standard UDC 621.791.35.048:543.24/.25:543.852.1BSENISO9455-3:1995 This British
2、 Standard, having been prepared under the directionof the Non-ferrous Metals Standards Policy Committee, was published underthe authority of the Standards Board and comes intoeffect on 15 February1995 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference N
3、FM/27 Draft for comment90/46341 DC ISBN 0 580 22884 3 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oesterreichisches Normungs
4、institut Belgium Institut belge de normalisation Denmark Dansk Standard Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Irelan
5、d National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y
6、 Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation UnitedKingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSENISO9455-3:1995 BSI 11-1999 i Contents Page Cooperating organizations Inside front cove
7、r National foreword ii Foreword 2 1 Scope 3 2 Normative references 3 3 Method A: Potentiometric titration method 3 4 Method B: Titration method with visual end-point 4 5 Precision 5 6 Test report 5 Annex ZA (normative) Normative references to international publicationswiththeir relevant European pub
8、lications 6 National annex NA (informative) Committees responsible Inside back coverBSENISO9455-3:1995 ii BSI 11-1999 National foreword This British Standard has been prepared under the direction of the Non-ferrous Metals Standards Policy Committee and is the English language version ofENISO9455-3:1
9、994 Soft soldering fluxes Test methods Part3:Determination of acid value, potentiometric and visual titration methods, published by the European Committee for Standardization (CEN). It is identical withISO9455-3:1992 Soft soldering fluxes Test methods Part3:Determination of acid value, potentiometri
10、c and visual titration methods, published by the International Organization for Standardization (ISO). Textual error. When implementing the English language version ofENISO9455-3 as the national standard, the textual error given below was discovered. It has been reported to CEN. In the foreword, the
11、 name ofISO/TC44 should be Welding and allied processes. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from leg
12、al obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN ISO title page, pages 2 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicat
13、ed in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 9455-3 September 1994 UDC 621.791.35.048:543.24/.25:543.852.1 Descriptors: Soldering, soldering fluxes, chemical analysis, determination, acid number, volumetric analysis English version Soft
14、 soldering fluxes Test methods Part3:Determination of acid value, potentiometric and visual titration methods (ISO9455-3:1992) Flux de brasage tendre Mthodes dessai Part3: Dtermination de lindice dacide par des mthodes de titrage potentiomtrique et visuel (ISO9455-3:1992) Flumittel zum Weichlten Prv
15、erfahren Teil3: Bestimmung des Surewertes, potentiometrische und visuelle Titrationsmethoden (ISO9455-3:1992) This European Standard was approved by CEN on1994-09-06. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Sta
16、ndard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French
17、, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, Fra
18、nce, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 19
19、94 Copyright reserved to CEN members Ref. No. EN ISO9455-3:1994 EENISO9455-3:1994 BSI 11-1999 2 Foreword This European Standard was taken over by the Technical CommitteeCEN/TC121, Welding, from the work ofISO/TC44, Soft soldering fluxes Test methods, of the International Standards Organization (ISO)
20、 1) . CEN/TC121 had decided to submit the final draft for Unique Acceptance Procedure. The result was positive. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest byMarch1995, and conflicting national s
21、tandards shall be withdrawn at the latest byMarch1995. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Port
22、ugal, Spain, Sweden, Switzerland, UnitedKingdom. 1) Seenational foreword for details of textual error.ENISO9455-3:1994 BSI 11-1999 3 1 Scope This part ofISO9455 specifies two methods for the determination of the acid value of a flux of types1 and2 only, as defined inISO9454-1. Method A is a potentio
23、metric titration method and is to be considered as the reference method. Method B is an alternative, visual end-point, titration method. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part ofISO9455. At the time
24、of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part ofISO9455 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain regist
25、ers of currently valid International Standards. ISO 9454-1:1990, Soft soldering fluxes Classification and requirements Part1:Classification, labelling and packaging. ISO 9455-1:1990, Soft soldering fluxes Test methods Part1: Determination of non-volatile matter, gravimetric method. ISO 9455-2:, Soft
26、 soldering fluxes Test methods Part2: Determination of non-volatile matter, ebulliometric method 2) . 3 Method A: Potentiometric titration method 3.1 Principle A prepared, weighed sample of the flux is dissolved in a suitable solvent. The resulting solution is titrated with standard tetrabutyl ammon
27、ium hydroxide solution, using a glass electrode, the pH or mV readings being recorded simultaneously. From the graph of volume of titrant against pH or mV readings, the point of inflexion is determined, from which the acid value is calculated. NOTE 1As fluxes of classes1.1.3 and1.2.3 (seeISO9454-1)
28、may lose some acidity during the determination of non-volatile matter, the non-volatile matter obtained from carrying out the procedure ofISO9455-1 orISO9455-2 on these classes of flux should not be used for this determination. 3.2 Reagents Use only reagents of recognized analytical quality and only
29、 distilled, or deionized, water. 3.2.1 Tetrabutyl ammonium hydroxide (CH 3 CH 2 CH 2 CH 2 ) 4 N(OH)0,1 M(0,1mol/l). Use a commercially available standard solution or one prepared from a commercially available concentrated standard solution by dilution with propan-2-ol(3.2.2). Alternatively, prepare
30、an0,1mol/l tetrabutyl ammonium hydroxide solution by diluting commercial concentrated solution with propan-2-ol and standardize this solution against an accurately weighed amount of benzoic acid (about0,5g) dissolved in dimethylformamide, previously neutralised to thymol blue. 3.2.2 Propan-2-ol (CH
31、3 ) 2 CHOH, neutralized with tetrabutyl ammonium hydroxide solution(3.2.1) to a faint pink colour, using phenolphthalein as indicator. 3.2.3 Ethanol (C 2 H 5 OH), anhydrous, neutralized with tetrabutyl ammonium hydroxide solution(3.2.1) to a faint pink colour using phenolphthalein as indicator. 3.2.
32、4 Toluene (C 6 H 5 CH 3 ), neutralized with tetrabutyl ammonium hydroxide solution(3.2.1) to a faint pink colour using phenolphthalein as indicator. 3.2.5 Ethanol/toluene mixture. Mix equal volume of the anhydrous ethanol(3.2.3) and toluene(3.2.4). 3.3 Apparatus Usual laboratory apparatus and, in pa
33、rticular, the following. 3.3.1 Millivoltmeter or pH meter. 3.3.2 Glass electrode 3.3.3 Saturated calomel, or silver chloride/silver, electrode 3.3.4 Magnetic, or mechanical, stirrer, with variable speed drive. 3.4 Procedure By preliminary experiments, determine whether the sample is soluble in propa
34、n-2-ol, anhydrous ethanol, toluene or the ethanol/toluene mixture. If it is not completely soluble in any of these solvents, select the one in which it appears to be the most soluble. If it is equally soluble in all four solvents then use propan-2-ol. Carry out the following procedure, in triplicate
35、, on the flux sample. Weigh, to the nearest0,001g, approximately0,5g of the solid flux sample, or2,0g of the liquid flux sample taking steps to prevent loss of volatile matter during the weighing. Transfer the weighed sample to a250ml low form beaker. 2) To be published.ENISO9455-3:1994 4 BSI 11-199
36、9 Add100ml propan-2-ol(3.2.2) or the selected solvent(3.2.3 to3.2.5), according to the solubility characteristics of the flux. Cover with a watch glass and dissolve the flux by gentle agitation. Place the beaker on the stand of the titration assembly with the electrodes, stirrer and burette in posit
37、ion. Adjust the speed of the stirrer to give vigorous stirring without splashing. Titrate with the tetrabutyl ammonium hydroxide solution(3.2.1) adding1ml portions and recording the pH, or mV meter readings after each addition. As the end-point is approached, reduce the additions of titrant to0,1ml
38、and continue titrating past the end-point. Plot the pH, or potential values against the volume of titrant added to obtain the titration curve. The point of inflexion of the curve corresponds to the end-point of the titration. NOTE 2The point of inflexion of the curve may conveniently be determined b
39、y using the derivative curve. Carry out a blank determination, using all reagents, for comparison purposes. 3.5 Calculation of results The acid value is expressed in milligrams of potassium hydroxide per gram of non-volatile matter, regardless of the alkali used to perform the titration. The acid va
40、lue (expressed in milligrams of potassium hydroxide per gram of non-volatile matter) is given by where The acid value of the flux under test is calculated as the mean of the results obtained on each of the three test samples. 4 Method B: Titration method with visual end-point 4.1 Principle A prepare
41、d, weighed sample of the flux is dissolvedin propan-2-ol, ethanol, toluene, or an ethanol/toluene mixture. The solution is then titrated with standard potassium hydroxide solution and the acid value is calculated. NOTE 3As fluxes of classes1.1.3 and1.2.3 (seeISO9454-1) may lose some acidity during t
42、he determination of non-volatile matter, the non-volatile matter obtained from carrying out the procedure ofISO9455-1 orISO9455-2 on these classes of flux should not be used for this determination. 4.2 Reagents Use only reagents of recognized analytical quality and only distilled, or deionized, wate
43、r. 4.2.1 Ethanol, anhydrous, neutralized with potassium hydroxide,0,1mol/l in alcohol(4.2.5), to a faint pink colour using phenolphthalein as indicator. 4.2.2 Toluene, neutralized with potassium hydroxide,0,1mol/l in alcohol(4.2.5), to a faint pink colour using phenolphthalein as indicator. 4.2.3 Et
44、hanol/toluene mixture. Mix equal volumes of the anhydrous ethanol(4.2.1), and toluene(4.2.2). 4.2.4 Propan-2-ol, neutralized with potassium hydroxide,0,1mol/l in alcohol(4.2.5), to a faint pink colour using phenolphthalein as indicator. 4.2.5 Potassium hydroxide solution,0,1mol/l in alcohol. Use a c
45、ommercially available standard solution or one prepared from a commercially available concentrated standard solution by dilution with ethanol(4.2.1). Alternatively, prepare a0,1mol/l potassium hydroxide solution by dissolving3g 0,1g potassium hydroxide (KOH) in500ml of ethanol(4.2.1) and standardize
46、 this solution against an accurately weighed amount of benzoic acid (about0,5g) dissolved in ethanol(4.2.1). 4.2.6 Phenolphthalein indicator solution. Add1g of phenolphthalein to approximately50ml methanol and mix. When dissolved, dilute to100ml with methanol and mix. 4.3 Apparatus Ordinary laborato
47、ry apparatus is required. V is the volume, in millilitres, of tetrabutyl ammonium hydroxide solution used, minus the volume needed to titrate the blank; M is the molarity of the tetrabutyl ammonium hydroxide solution(3.2.1); m is the mass, in grams, of the sample taken; S is the percentage non-volat
48、ile matter content of the sample, determined as described inISO9455-1 orISO9455-2 (for solid flux samples, S =100). 5611VM mS -ENISO9455-3:1994 BSI 11-1999 5 4.4 Procedure By preliminary experiments, determine whether the sample is soluble in propan-2-ol, anhydrous ethanol, toluene or the ethanol/to
49、luene mixture. If it is not completely soluble in any of these solvents, select the one in which it appears to be the most soluble. If it is equally soluble in all four solvents then use ethanol as the selected solvent. Carry out the following procedure in triplicate on the flux sample. Weigh to the nearest0,001g sufficient of the flux sample to correspond to approximately1g of non-volatile matter (seeISO9455-1 orISO9455-2) taking steps in the case of liquid flux samples to prevent loss of
