1、BS EN 16813:2016Thermal spraying Measurement of the electricalconductivity of thermalsprayed non-iron metalcoatings by means of eddycurrent methodBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS EN 16813:2016 BRITISH STANDARDNational forewordThis British Standard i
2、s the UK implementation of EN 16813:2016. The UK participation in its preparation was entrusted to TechnicalCommittee STI/40, Thermal spraying and thermally sprayed coatings. A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not p
3、urport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 88075 9 ICS 25.220.20 Compliance with a British Standard cannot confer immunity from legal obl
4、igations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS EN 16813:2016EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16813 November 2016 ICS 2
5、5.220.20 English Version Thermal spraying - Measurement of the electrical conductivity of thermal sprayed non-iron metal coatings by means of eddy current method Projection thermique - Mesurage de la conductivit lectrique des revtements mtalliques non ferreux obtenus par projection thermique, laide
6、de la mthode par courants de Foucault Thermisches Spritzen - Messung der elektrischen Leitfhigkeit thermisch gespritzter Nichteisenmetall-Schichten mittels Wirbelstromverfahren This European Standard was approved by CEN on 24 September 2016. CEN members are bound to comply with the CEN/CENELEC Inter
7、nal Regulations which stipulate the conditions for giving this European Standard 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 CEN-CENELEC Management Centre or to any
8、CEN member. This European Standard exists in three official versions (English, French, 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 CEN-CENELEC Management Centre has the same status as the official ver
9、sions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
10、 Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitat
11、ion in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16813:2016 EBS EN 16813:2016EN 16813:2016 (E) 2 Contents Page European foreword . 3 Introduction 4 1 Scope 5 2 Normative references 5 3 Terms and definitions . 5 4 Measuring process 6 4.1 Measuring method 6 4.2
12、 Calibration standard 7 4.3 Measuring frequency and penetration depth . 8 4.4 Measuring instruments . 8 4.5 Factors, which have effects on the uncertainty of the measurement . 9 4.6 Limit of application 9 5 Procedure of the measurement 10 5.1 Calibration of the measuring instruments 10 5.2 Measureme
13、nt . 10 6 Measuring results and their assessment . 10 7 Test report and documentation 11 Annex A (informative) Record for the applied Electrical Conductivity Measurement 12 A.1 General . 12 A.2 Component/part . 12 A.3 Surface preparation for spraying . 12 A.4 Spraying procedure for component/part 12
14、 A.5 Preparation of measurement 13 A.6 Measuring instrument 13 A.7 Result of the measured electrical conductivity . 13 Bibliography . 14 BS EN 16813:2016EN 16813:2016 (E) 3 European foreword This document (EN 16813:2016) has been prepared by Technical Committee CEN/TC 240 “Thermal spraying and therm
15、ally sprayed coatings”, the secretariat of which is held by DIN. 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 by May 2017, and conflicting national standards shall be withdrawn at the latest by Ma
16、y 2017. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organisations of th
17、e following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherl
18、ands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 16813:2016EN 16813:2016 (E) 4 Introduction In many applications, the electrical conductivity is a relevant technical parameter. For testing of imperfections in components or
19、technological material properties the eddy current method can be very well applied. It can be detected or determined, for example: defects in welds; imperfections or change in the structure of a component, for example, due to aging processes in structures made out of aluminium; change in structure c
20、aused by temperature effects; thickness; physical material properties such as the electrical conductivity. Due to an interaction between high frequency magnetic fields, emitted from a measuring probe, and the eddy currents induced in the object to be measured the electrical conductivity can be deter
21、mined, e.g. according to ASTM E 1004 or can be used for fast and contact less measurements of a coating thickness according to EN ISO 21968. Due to the manufacturing process thermal sprayed coatings contain a layer orientated structure. Dependent on the material used, it can also contain oxides and/
22、or inclusions as well as porosity created due to splat boundary effects during spraying. Besides the structure with its grain boundaries, dislocations, internal stresses and impurities, e.g. oxide skins, the specific gravity of a material plays an important role for the level of the electrical condu
23、ctivity. In order to produce the highest possible level of electrical conductivity in the coating, the influencing factors for the thermal spraying process should be minimized. BS EN 16813:2016EN 16813:2016 (E) 5 1 Scope This European standard specifies the procedure of the measurement of the electr
24、ical conductivity of non-Ferro-magnetic thermal sprayed coatings. By this measurement the absolute value of the electrical conductivity in the coating sprayed on component can be determined as well as also deviations from the agreed rated value can be used to control a running production. With that,
25、 a remarkable contribution can be applied to process and quality assurance measures of a manufacture process. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edi
26、tion cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 21968, Non-magnetic metallic coatings on metallic and non-metallic basis materials - Measurement of coating thickness - Phase-sensitive eddy-current method (ISO 21968)
27、 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 electrical conductivity physical value, which shows the ability of a material in this case of a thermal sprayed coating to conduct the current Note 1 to entry: It is defined to be the constant
28、of proportionality between the current density and the electrical field intensity within the general Formula (1) of the ohmic law. is measured in S/m. =J E(1) where J is the current density; is the electrical conductivity; E is the field intensity. 3.2 electrical resistance R value, which defines th
29、e electrical voltage, which is needed that a certain current can flow through an electrical conductor Note 1 to entry: The unit is ohm (). BS EN 16813:2016EN 16813:2016 (E) 6 3.3 specific electrical resistivity property of material, which is the result of the electrical resistance in a homogenous pa
30、rt with a constant current intensity distribution across the constant cross-section and length of the conductor and an ohmic resistance Note 1 to entry: The specific electrical resistance, see Formula (2), depends on the temperature of material and is the reciprocal value of the electrical conductiv
31、ity ( = 1/). The unit is ohm metre ( m). =ARL(2) where is the specific electrical resistivity in m; R is the ohmic resistance; A is the constant cross-section of the conductor; L is the length of the conductor. 4 Measuring process 4.1 Measuring method Measuring of the absolute value of the electrica
32、l conductivity takes place usually by a current voltage measurement. However, this method is usually applied in laboratories only. If the electrical conductivity shall be determined in a component on site, primarily eddy current processes are applied. To measure the electrical conductivity of non-ma
33、gnetic metals, such as aluminium, copper, brass, titanium, chrome-nickel-steel, etc. Therefore, the phase-sensitive eddy current measurement procedure is very suitable. By that, the measuring probe fed from a generator with alternating current of a certain frequency is to be put to the object to be
34、measured or to be brought into small distance to its surface. This exciter current generates a magnetic field of high frequency, which induces eddy currents in the material to be tested (in this case the coating respectively the base material), their intensity and penetration depth depend on its ele
35、ctrical conductivity. On the other hand the magnetic field induced by eddy currents overlaps the generating field. The generated resulting magnetic field is detected by a measuring coil. By that, the induced voltage is a function of the electrical conductivity of the object to be measured and can be
36、 used as a signal for its measuring. See Figure 1. BS EN 16813:2016EN 16813:2016 (E) 7 Key 1 ferrite core of the probe 4 measuring signal 2 exiting current 5 eddy current induced 3 high frequency magnetic alternating field 6 electrically conductive non-ferrous-alloy Figure 1 Phase-sensitive eddy cur
37、rent measuring method Using the phase-sensitive eddy current measurement procedure the phase changing between exciter current and measuring signal is to be transferred into a conductivity value. This measuring value is independent from the distance between the probe and the coating surface for a cer
38、tain arrangement, which depends on the type of the probe. By that, a non-contactable determination of the conductivity can be applied also using this method, for example, below a varnish or a synthetic material coat. Using an adequate measuring frequency the influence of the surface roughness remain
39、s low. 4.2 Calibration standard Using the phase-sensitive eddy current measurement procedure the measuring value found in the component will be compared to the calibration standard as a reference standard, which conductivity is very well known. Standards for calibration of the measuring instrument a
40、re available for the whole conductivity range. Usually, they are also supplied from the measuring instrument producer. Because the calibration standards are subject to changes in properties due to use they have to be recalibrated at regular time periods or to be replaced. BS EN 16813:2016EN 16813:20
41、16 (E) 8 4.3 Measuring frequency and penetration depth The penetration depth of the eddy current is defined by the conductivity and the measuring frequency f. Generally, the penetration depth 0of the eddy current in a non-ferrous-alloy is given by: 0R503=f (3) where 0is the penetration depth of the
42、eddy current in a non-ferrous-alloy; f is the measuring frequency in Hz; is the electrical conductivity in MS/m; Ris the permeability = 1 for non-magnetic materials. The penetration depth of the eddy current is also decisive for the minimally permissible thickness of the object to be measured. In or
43、der to achieve complete saturation within the coating to be measured a penetration depth Sshall be taken: s0= 2,5-3(4) where Sis the penetration depth of the eddy current in the coating; 0is the penetration depth of the eddy current in a non-ferrous-alloyl. Due to the usually low thickness of therma
44、l sprayed coatings, a higher measuring frequency shall be taken, therefore. Usually, such measuring frequencies are in the range of 480 kHz to more than 1 MHz. They are available in commercial instruments. Due to the increase of the skin effect with increasing frequency, however, the measuring frequ
45、ency should not be selected unnecessary high, because the measuring result could not be representative for the coating then. In the case of increasing measuring frequency the negative influence of surface roughness to the measuring result also increases. The higher the frequency the smoother should
46、be the surface. Using the phase-sensitive eddy current measurement procedure the effect remains low. 4.4 Measuring instruments Nowadays, instruments to measure the electrical conductivity are equipped as to be: independent instrument for control measurement in the laboratory; integrated instrument w
47、ith an automatic measurement in installations for manufacture; hand-operated instrument for measurements in the work shop. BS EN 16813:2016EN 16813:2016 (E) 9 Usually, the attachment contains: collection of measuring data and connections to PC, printer and to have the capability of data storing; mea
48、suring range: e.g. 0,5 MS/m to 65 MS/m respectively 1 % to 112 % IACS (International Annealed Copper Standard). Often a disturbing effect of distance variations can be suppressed when using a scanning probe. Therefore, measuring tasks can be served successfully, where a direct contact to the metalli
49、c surface is not possible or undesirable, such as for varnishes or moved measuring objects. 4.5 Factors, which have effects on the uncertainty of the measurement Following influencing factors can lead to deviations of the measuring result: distance from the probe to the component surface, also called take-off effect, is too large or not sufficiently compensated or dirt particles are in between; distance from the probe to an edge is too small or not sufficiently compensated (necessary distance can be found
