1、BRITISH STANDARD BS1468:1967 Incorporating Amendment No.1 Specification for Tin anodes and tin salts for electroplatingBS1468:1967 This BritishStandard, having been approved by the SurfaceCoatings (otherthanpaints) IndustryStandards Committeeand endorsed bytheChairman of the Engineering Divisional C
2、ouncil,was published undertheauthority of the GeneralCouncil on 14 March1967 BSI01-2000 First published November1948 First revision March1967 The following BSI references relate to the work on this standard: Committee reference SRE/8 Draft for comment D65/2522 ISBN 0 580 01744 3 Co-operating organiz
3、ations The Surface Coatings (other than Paints) Industry Standards Committee, under whose supervision this BritishStandard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Aluminium Federation Assay Offices Committee of
4、GreatBritain Association of Metal Sprayers British Bolt, Nut, Screw and Rivet Federation British Cycle and Motor Cycle Industries Association Limited* British Electrical and Allied Manufacturers Association British Iron and Steel Federation British Jewellers Association British Non-ferrous Metal Res
5、earch Association* Chemical Industries Association* Electricity Council, the Central Electricity Generating Board and the Area Boards in England and Wales Electronic Engineering Association Engineering Equipment Users Association Institute of Metal Finishing* Institute of Sheet Metal Engineers Insti
6、tute of Vitreous Enamellers Greater London Council Metal Finishing Association* Ministry of Aviation Ministry of Defence, Army Department Ministry of Defence, Navy Department Society of Motor Manufacturers and Traders Limited* Tin Research Institute* Vitreous Enamel Development Council Zinc Developm
7、ent Association* The scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this BritishStandard: British Federation of Master Printers British Sulphate of Copper Ass
8、ociation Chemical Society Institution of Chemical Engineers Royal Institute of Chemistry Scientific Instrument Manufacturers Association Society of Chemical Industry UnitedKingdom Cutlery and Silverware Manufacturers Association Individual firms Amendments issued since publication Amd. No. Date of i
9、ssue Comments 122 October1968 Indicated by a sideline in the marginBS1468:1967 BSI 01-2000 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Tin Anodes 1 2.1 Physical form 1 2.2 Chemical composition 1 2.3 Sampling 1 3 Stannous sulphate 1 3.1 Physical form and appe
10、arance 1 3.2 Chemical composition 1 3.3 Impurities 1 3.4 Packing 1 3.5 Sampling and size of sample 1 4 Sodium stannate and potassium stannate 2 4.1 Physical form and appearance 2 4.2 Chemical composition 2 4.3 Impurities 2 4.4 Packing 2 4.5 Sampling and size of sample 2 Appendix A Determination of i
11、nsoluble matter in stannous sulphate 3 Appendix B Determination of stannous tin in stannous sulphate 3 Appendix C Determination of chloride in stannous sulphate 3 Appendix D Determination of antimony in stannous sulphate 4 Appendix E Determination of arsenic in stannous sulphate 4 Appendix F Determi
12、nation of free sulphuric acid in stannous sulphate 4 Appendix G Determination of insoluble matter in sodium or potassium stannate 5 Appendix H Determination of soluble tin in sodium or potassium stannate 5 Appendix J Determination of free alkali in sodium or potassium stannate 7 Appendix K Determina
13、tion of lead in sodium or potassium stannate 7 Appendix L Determination of antimony in sodium or potassium stannate 7 Appendix M Determination of arsenic in sodium or potassium stannate 8 Appendix N Determination of nitrate in sodium or potassium stannate 8 Appendix P Determination of chloride in so
14、dium or potassium stannate 9 Appendix Q Determination of sodium in potassium stannate 9 Figure 1 Assembly for reduction of tin 6BS1468:1967 ii BSI 01-2000 Foreword This standard makes reference to the following BritishStandards: BS612, Nessler cylinders. BS3252, Ingot tin. BS3338, Methods for the sa
15、mpling and analysis of tin and tin alloys Part1:Sampling of ingot tin. BS3978, Water for laboratory use. This BritishStandard is one of a series of standards that has been prepared to meet the requirements of electroplaters, others in the series being: BS558, 564, Nickel anodes and nickel salts for
16、electroplating. BS622, Cyanides for electroplating. BS1561, Silver anodes and silver salts for electroplating. BS2656, Zinc anodes, zinc cyanide and zinc oxide for electroplating. BS2657, Fluoroboric acid and metallic fluoroborates for electroplating. BS2867, Copper sulphate for electroplating. BS28
17、68, Cadmium anodes and cadmium oxide for electroplating. BS2884, Copper cyanide for electroplating. Wherever appropriate, BritishStandard laboratory glassware should be used in the methods of test. A British Standard does not purport to include all the necessary provisions of a contract. Users of Br
18、itish Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to10, an inside back cover and a back cover
19、. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS1468:1967 BSI 01-2000 1 1 Scope This BritishStandard specifies requirements for tin anodes, stannous sulphate, sodium stannate and
20、 potassium stannate for electroplating. 2 Tin anodes 2.1 Physical form Tin anodes shall be supplied in cast, rolled or extruded form as specified by the purchaser. NOTEThe attention of makers, dealers and users is directed to the fact that dirt and extraneous matter adhering to the anode surface is
21、often detrimental to the working of a plating bath. Care should be taken, therefore, in transit and storage to keep anodes as clean as possible, but in any case they should be chemically cleaned before being put into use. 2.2 Chemical composition 2.2.1 Pure tin anodes. Tin anodes shall comply with t
22、he requirements for refined tin, Grade T2 of BS3252 1) . 2.2.2 Alloy tin anodes. Certain elements are sometimes added to tin for anodes to improve the efficiency of anodic dissolution in alkaline tin plating baths. These additions produce no deleterious effects on the baths and are not co-deposited
23、with the tin. The tin used for the production of these anodes shall comply with the requirements for refined tin, Grade T2 of BS3252 1) . 2.3 Sampling For the purposes of examination under this standard, a representative sample shall be taken in accordance with the procedure described in BS3338-1 2)
24、 . 3 Stannous sulphate 3.1 Physical form and appearance Stannous sulphate shall usually be of a pale cream crystalline structure and shall correspond to the formula SnSO 4 . 3.2 Chemical composition Stannous sulphate shall contain not less than50% of stannous tin (equivalent to90.4% of stannous sulp
25、hate) and not more than2% of free sulphuric acid when determined by the methods given in Appendix B and Appendix F. NOTECommercial stannous sulphate almost invariably contains some stannic sulphate. The minimum content of stannous tin specified automatically limits the maximum stannic sulphate conte
26、nt to a safe value. 3.3 Impurities The following impurities if present shall not exceed the limits given when the impurities are determined by the method described in the appropriate appendix. 3.4 Packing Stannous sulphate shall be packed in air-tight containers preferably having replaceable closure
27、s. NOTEOn keeping, especially if left exposed to the air, stannous sulphate undergoes hydrolysis and therefore cannot be packed in iron or steel containers. To prevent deterioration it should at all times be stored in air-tight containers. 3.5 Sampling and size of sample A representative sample of t
28、he material, weighing not less than250g is necessary for the purpose of examination under this standard. The sample shall be taken from freshly-opened packages and shall be packed in a clean, dry and air-tight bottle and sealed. 1) BS3252, “Ingot tin”. 2) BS3338, “Methods for the sampling and analys
29、is of tin and tin alloys”, Part1, “Sampling of ingot tin”. Impurity % (max.) Appendix Insoluble matter Chloride, expressed as Cl Antimony, expressed as Sb Arsenic, expressed as As 1.0 0.5 0.1 0.01 Appendix A Appendix C Appendix D Appendix EBS1468:1967 2 BSI 01-2000 4 Sodium stannate and potassium st
30、annate 4.1 Physical form and appearance Sodium stannate and potassium stannate shall be white powders usually corresponding to the formulaeNa 2 SnO 3 .3H 2 O and K 2 SnO 3 .3H 2 O. 4.2 Chemical composition Sodium stannate shall contain not less than40% and potassium stannate not less than38% of solu
31、ble tin when determined by the method given in Appendix H and not more than6% and1.5% respectively of free alkali when determined by the method given in Appendix J. NOTEThe tin content of the pure compound is, in the case of sodium stannate,44.5% and in potassium stannate39.7%, but owing to the pres
32、ence of free alkali, the commercial salts almost invariably contain less than the theoretical amount of tin. 4.3 Impurities The following impurities if present shall not exceed the limits given when the impurities are determined by the method described in the appropriate appendix. 4.4 Packing Sodium
33、 and potassium stannates shall be packed in air-tight containers, preferably having replaceable closures. NOTEIn the presence of moist air, sodium and potassium stannates rapidly deteriorate owing to the absorption of carbon dioxide, the salts tending to become less soluble in water in consequence.
34、It is, therefore, essential to store them at all times in air-tight containers. 4.5 Sampling and size of sample A representative sample of the material, weighing not less than250g is necessary for the purpose of examination under this standard. The sample shall be taken from freshly-opened packages
35、and shall be packed in a clean, dry and air-tight bottle and sealed. NOTEThe BritishStandards Institution is the owner of a registered certification trade mark. This is shown below, enclosed in the words “Approved to BritishStandard”. This mark can be used only by manufacturers licensed under the ce
36、rtification mark scheme operated by the BSI. The presence of this mark on or in relation to a product is an assurance that the goods have been produced to comply with the requirements of the BritishStandard under a system of supervision, control and testing operated during manufacture and including
37、periodical inspection at the manufacturers works in accordance with the certification mark scheme of the BSI. Further particulars of the terms of licence may be obtained from the Director, BritishStandards Institution,2 Park Street, London,W.1. Impurity In sodium stannate In potassium stannate Appen
38、dix Insoluble matter Lead Antimony Arsenic Nitrate Chloride Sodium % (max.) 0.25 0.05 0.05 0.01 0.25 as NaNO 3 1.0 as NaCl % (max.) 0.25 0.025 0.05 0.01 0.25 as KNO 3 1.0 as KCl 0.01 Appendix G Appendix K Appendix L Appendix M Appendix N Appendix P Appendix QBS1468:1967 BSI 01-2000 3 Appendix ADeter
39、mination of insoluble matter in stannous sulphate A.1 Reagents All reagents shall be of a recognized analytical reagent quality, and distilled water 3)shall be used whenever water is specified. Sulphuric acid(2%v/v). Dilute20ml of sulphuric acid (sp. gr.1.84) to one litre. A.2 Procedure Dissolve10g
40、of the sample in200ml of2% sulphuric acid without heating. Filter through an11 cm filter paper (Whatman No.40) containing a little filter pulp. Wash the residue with100ml of2% sulphuric acid and then wash free from acid with water. Ignite the residue at900 C in a silica crucible, cool and weigh. Per
41、centage of total insoluble matter=weight of residue (g) 10. Transfer the filtrate and washings to a500ml graduated flask, make up to the mark with2% sulphuric acid and reserve for the determination of impurities (Solution A). Appendix B Determination of stannous tin in stannous sulphate B.1 Reagents
42、 All reagents shall be of a recognized analytical reagent quality, and distilled water 3)shall be used whenever water is specified. Sulphuric acid(2%v/v)(seeAppendix A) Hydrochloric acid (sp. gr.1.161.18) Standard potassium iodate/iodine solution,(1mlN 0.01g of tin). Dissolve6.02g of potassium iodat
43、e (previously dried at105110 C) in400ml of water containing1g of sodium hydroxide. Add30g of potassium iodide and dilute to1litre in a graduated flask. Starch solution. Make a suspension of0.5g of starch in10ml of water. Add to90ml of boiling water, cool and dilute to100ml. Prepare freshly each day.
44、 B.2 Procedure Dissolve0.800g of the sample in20ml of2% sulphuric acid without heating. To the solution add5ml of hydrochloric acid,20ml of water and5ml of starch solution. Titrate with a minimum of shaking with standard potassium iodate/iodide solution to a permanent blue colour. Percentage of stan
45、nous tin=vol. of iodate(ml) 1.25. Appendix CDetermination of chloride in stannous sulphate C.1 Reagents All reagents shall be of a recognized analytical reagent quality, and distilled water 3)shall be used whenever water is specified. Solution A(seeAppendix A) Nitric acid (sp. gr.1.42) Silver nitrat
46、e,0.1N Ammonium thiocyanate,0.1N Ammonium ferric sulphate(10%w/v). Dissolve10g of ammonium ferric sulphate in water, add10ml of nitric acid (sp. gr.1.42) and dilute to100ml. C.2 Procedure To100ml of Solution A add10ml of nitric acid (sp. gr.1.42) and heat to oxidize the stannous tin. Cool, add10ml o
47、f0.1N silver nitrate solution and5ml of ammonium ferric sulphate and titrate the excess silver nitrate with0.1N ammonium thiocyanate solution to the appearance of a faint brown coloration. Percentage of chloride=0.177(10 m) where m=vol. of0.1N ammonium thiocyanate (ml). 3) BS3978, “Water for laborat
48、ory use”.BS1468:1967 4 BSI 01-2000 Appendix DDetermination of antimony in stannous sulphate D.1 Reagents All reagents shall be of a recognized analytical reagent quality, and distilled water 4)shall be used whenever water is specified. Hydrochloric acid (sp. gr.1.161.18) Potassium chlorate Potassium
49、 iodide Sodium thiosulphate0.01N Starch solution(seeAppendix B) D.2 Procedure Dissolve5g of the sample in100ml of water and40ml of hydrochloric acid. Add1.5g of potassium chlorate and boil to expel all traces of chlorine(15 minutes). Cool, dilute to200ml, add1g of potassium iodide and titrate the liberated iodine with0.01N sodium thiosulphate solution, using starch as indicator. Percentage of antimony=vol. of0.01N sodium thiosulphate(ml) 0.012. NOTEThis method is not specific for antimony, but other metals liable to cause interference are not likely to be pres
