1、BRITISH STANDARDBS ISO 16232-8:2007Road vehicles Cleanliness of components of fluid circuits Part 8: Particle nature determination by microscopic analysisICS 13.040.50; 43.180g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3
2、g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS ISO 16232-8:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 June 2007 BSI 2007ISBN 978 0 580 50921 6National forewordThis British Standard was published by B
3、SI. It is the UK implementation of ISO 16232-8:2007.The UK participation in its preparation was entrusted to Technical Committee MCE/22, Engines for road vehicles.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to in
4、clude all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsReference numberISO 16232-8:2007(E)INTERNATIONAL STANDARD ISO1
5、6232-8First edition2007-06-01Road vehicles Cleanliness of components of fluid circuits Part 8: Particle nature determination by microscopic analysis Vhicules routiers Propret des composants des circuits de fluide Partie 8: Dtermination de la nature des particules par analyse microscopique BS ISO 162
6、32-8:2007ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 2 4 Principles. 2 5 Equipment . 2 5.1 General. 2 5.2 Analysis equipment 3 5.3 Environmental conditions 4 5.4 Health and Safety 4 6 Calibration . 5 7 Procedure 5 7.1 General. 5 7.2
7、Element analysis procedure 5 8 Expression of results . 6 Annex A (informative) Example of classifying particles according to their chemical composition 7 BS ISO 16232-8:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS
8、O member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, gove
9、rnmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC
10、Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member
11、 bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 16232-8 was prepared by Technical Committee ISO/TC 22, Road vehicles, Sub
12、committee SC 5, Engine tests. ISO 16232 consists of the following parts, under the general title Road vehicles Cleanliness of components of fluid circuits: Part 1: Vocabulary Part 2: Method of extraction of contaminants by agitation Part 3: Method of extraction of contaminants by pressure rinsing Pa
13、rt 4: Method of extraction of contaminants by ultrasonic techniques Part 5: Method of extraction of contaminants on functional test bench Part 6: Particle mass determination by gravimetric analysis Part 7: Particle sizing and counting by microscopic analysis Part 8: Particle nature determination by
14、microscopic analysis Part 9: Particle sizing and counting by automatic light extinction particle counter Part 10: Expression of results BS ISO 16232-8:2007vIntroduction The presence of particulate contamination in a liquid system is acknowledged to be a major factor governing the life and reliabilit
15、y of that system. The presence of particles residual from the manufacturing and assembly processes will cause a substantial increase in the wear rates of the system during the initial run-up and early life, and may even cause catastrophic failures. In order to achieve reliable performance of compone
16、nts and systems, control over the amount of particles introduced during the build phase is necessary, and measurement of particulate contaminants is the basis of control. The ISO 16232 series has been drafted to fulfil the requirements of the automotive industry, since the function and performance o
17、f modern automotive fluid components and systems are sensitive to the presence of a single or a few critically sized particles. Consequently, ISO 16232 requires the analysis of the total volume of extraction liquid and of all contaminants collected using an approved extraction method. The ISO 16232
18、series has been based on existing ISO International Standards such as those developed by ISO/TC 131/SC 6. These International Standards have been extended, modified and new ones have been developed to produce a comprehensive suite of International Standards to measure and report the cleanliness leve
19、ls of parts and components fitted to automotive fluid circuits. This part of ISO 16232 defines a method of microscopic examination to determine the nature of contaminants which have been removed from the component under analysis and collected using an approved extraction method. It can be used at th
20、e same time to determine the particle size distribution as described in ISO 16232-7. BS ISO 16232-8:2007blank1Road vehicles Cleanliness of components of fluid circuits Part 8: Particle nature determination by microscopic analysis 1 Scope This part of ISO 16232 describes a method for determining the
21、nature of contaminant particles by identifying their elemental chemical composition using energy dispersive X-ray spectroscopy (EDX) in combination with a scanning electron microscope (SEM). The contaminant particles are extracted from automotive parts or components and deposited on the surface of a
22、 membrane filter. In addition to the number and size of particles as described in ISO 16232-7, this measurement gives the elemental composition of the particles analysed. This information can be used to classify the particles into likely material groups 1). This method cannot determine the nature of
23、 organic material 2). The analyses can either be carried out manually or fully automatically, provided the appropriate equipment is available. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cite
24、d applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 15632:2002, Microbeam analysis Instrumental specification for energy dispersive X-ray spectrometers with semiconductor detectors ISO 16232-1, Road vehicles Cleanliness of componen
25、ts of fluid circuits Vocabulary ISO 16232-2, Road vehicles Cleanliness of components of fluid circuits Method of extraction of contaminants by agitation ISO 16232-3, Road vehicles Cleanliness of components of fluid circuits Method of extraction of contaminants by pressure rinsing ISO 16232-4, Road v
26、ehicles Cleanliness of components of fluid circuits Method of extraction of contaminants by ultrasonic techniques ISO 16232-5, Road vehicles Cleanliness of components of fluid circuits Method of extraction of contaminants on functional test bench 1) The additional material information can be used to
27、 give a more detailed characterization of particles or to find their source in production process. The range of elements detected by the SEM/EDX system depends upon the design and configuration of the separate items. 2) Infrared or other techniques can be used to detect organic particles. BS ISO 162
28、32-8:20072 ISO 16232-7:2007, Road vehicles Cleanliness of components of fluid circuits Particle sizing and counting by microscopic analysis ISO 16232-10:2007, Road vehicles Cleanliness of components of fluid circuits Expression of results 3 Terms and definitions For the purposes of this document, th
29、e terms and definitions given in ISO 16232-1 apply. 4 Principles The entire volume of extraction liquid used to extract particles from the test component (as described in ISO 16232-2, ISO 16232-3, ISO 16232-4 and ISO 16232-5), is filtered and the separated particles are counted and sized using a SEM
30、 according to 16232-7. In the process, the sample to be imaged is scanned point-for-point in a vacuum using a finely-focused high-accelerated electron beam. This treatment with high-energy electrons leads the sample to give off X-rays that are characteristic of the chemical elements in the particle
31、being examined. By recording this spectrum using an EDX detector, it is possible to determine the elements in the residual contamination particles. The analysis of the intensity of the spectral lines also enables a quantification of the elements concerned. The result is the chemical composition of t
32、he particles investigated. Particles are located on the surface of the membrane filter using the Back Scattering Electron (BSE) detector of the SEM and an element analysis is then carried out only at these points. 5 Equipment 5.1 General All the equipment that is used for preparing the membrane filt
33、er or the components and software features of a SEM suitable for particle analysis is described in ISO 16232-7. BS ISO 16232-8:200735.2 Analysis equipment 5.2.1 Principle Figure 1 Diagrammatic representation of the membrane filter analysis using a SEM equipped with an EDX system used for element ana
34、lysis As shown in Figure 1, the principle set-up of this analysis and the device technology used are almost identical to those implemented for particle sizing and counting using an SEM (see 5.2 of ISO 16232-7:2007). For the element analysis, an additional detector (X-ray or EDX detector) (7) and the
35、 corresponding element analysis software (8) are required. For electron-optical systems, further requirements exist. 5.2.2 Electron optics The stability of the electron beam current is crucial to the quality of the analysis. As a reference, a deviation of approximately 1% per hour in the strength of
36、 the beam is acceptable. This is measured either by a Faraday cup which is introduced into the electron beam or from the counting rate of the EDX detector on an element standard. The cathode which generates the electrons shall be warmed until its emissions are stable. NOTE The cathode types of tungs
37、ten, LaB6and hot field emitters are all suitable for these measurements. However, devices with cold field emitters often show excessive levels of beam strength instability. When an X-ray detector is integrated into a scanning electron microscope, it is mounted onto the vacuum chamber so that the “di
38、rection of view” of the detector cuts across the electron beam at the working distance of the microscope. In order to be able to carry out reproducible measurements, all analyses must be performed using this working distance. The working distance between the work piece and the deflector lens varies
39、from unit to unit and will be specified by the manufacturer of the system. 5.2.3 X-ray detector The higher the energy dispersion of the detector, the better the resolution. This means that elements having X-ray lines close together in the spectrum will be better separated and a more accurate result
40、will be obtained. X-ray detector EDX Software Material analysis Element analysis Membrane filter (1) Electron optics (2) Back-scattered electron detector BSE (3) Image analysis (4) Single image analysis Multiple image analysis Motorized sample stage (5) Multiple image analysis (6) (7) (8) Microscope
41、- hardware BS ISO 16232-8:20074 5.2.4 Element analysis To obtain a correct result of the composition of elements, the EDX system shall be able to analyze the entire area of the detected particle. This means that the electron beam is guided to a number of measuring points over the particle during the
42、 EDX analysis. This reduces the risk which exists, when performing a measurement using only one point, that a non-homogeneity in the particle or a foreign substance adhering to it (e.g. production process materials such as oil or grease) be classified as being part of the particle itself, see Figure
43、 2. Figure 2 Example of suitable or non suitable particle analysis To make the characterization of the particles easier, the EDX system should possess the ability to group the particles into classes based on the percentage of elements in their composition (e.g. copper in connection with zinc is clas
44、sified as brass), see Classification Table in Annex A. Particles which do not fit to any material class with regard to chemical composition shall be counted in a separate class (e.g. unclassified particles). On completion of a fully-automated analysis, automatic systems shall be able to find individ
45、ual particles, analyze them manually and, where necessary, classify them afterwards. 5.2.5 Measurement limits The determination of a material is performed exclusively according to the composition in percent of the elements making up the particle. In order to obtain further information regarding thei
46、r exact chemical bonding from the chemical shift, the energy dispersion from EDX detectors is inadequate. Due to their lack of material contrast on a filter membrane, it is very difficult to classify organic compounds. Generally, organic compounds can be detected, but, because of their high carbon s
47、ignals, cannot be classified as being made of a specific material. Exceptions to this include, for example, synthetic materials containing elements additional to carbon, oxygen and nitrogen, such as halogenated plastics (PVC, PTFE, etc.). 5.3 Environmental conditions The cleanliness of the environme
48、nt where the analysis is performed has to be adapted to the presumed cleanliness of the component to be tested. This is validated when performing the blank test. The site for the microscope should be selected to avoid environmental factors such as vibration of the building, or external light from in
49、fluencing the imaging quality and accuracy of the particle measurement. If these factors cannot be controlled, appropriate measures shall be taken (vibration absorbers, encapsulation, etc.). 5.4 Health and Safety 5.4.1 Local Health and Safety procedures shall be followed at all times, any equipment shall be operated in accordance with the manufactures instructions and personal protection equipment used where appropriate. Fixed position, X, of electron beam: Not suitable for correct particle analysis Suitable analysis by
