STANDARD. ISO. First edition. Road vehicles — Cleanliness of components of fluid ISO’s member body in the country of the requester. STANDARD. ISO. First edition. Road vehicles — Cleanliness of components of fluid circuits —. Part 7: Particle sizing and counting by. Find the most up-to-date version of ISO at Engineering
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Particle nature determination by microscopic analysis ICS A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include 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. 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, governmental and non-governmental, in liaison with ISO, also take part in the work. 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. 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 consists of the following parts, under the general title Road vehicles — Cleanliness of components of fluid circuits: Method of extraction of contaminants by pressure rinsing Part 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 microscopic analysis Part 9: Particle sizing and counting by automatic light extinction particle counter Part 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 components 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 series has been drafted to fulfil the requirements of the automotive industry, since the function and performance of modern automotive fluid components and systems are sensitive to the presence of a single or a few critically sized particles.
Consequently, ISO requires the analysis of the total volume of extraction liquid and of all contaminants collected using an approved extraction method. 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 levels of parts and components fitted to automotive fluid circuits.
This part of ISO 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 the same time to determine the particle size distribution as described in ISO Particle nature determination by microscopic analysis 1 Scope This part of ISO describes a method for determining the 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 membrane filter. In addition to the number and size of particles as described in ISOthis 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 organic material 2. The analyses can either be carried out manually or fully automatically, provided the appropriate equipment is available.
CleanControlling – Restschmutzanalyse – ISO
For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document including any amendments applies. 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 highenergy electrons leads the sample to give off X-rays that are 162327- of the chemical elements in the particle 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 ios lines also enables a quantification of the elements concerned.
BS ISO 16232-7:2007
The result is the chemical composition of the 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. For the element analysis, an additional detector X-ray or EDX detector 7 and the corresponding element analysis software 8 are required. For electron-optical systems, further requirements exist.
This is measured either by a Faraday cup which is introduced into the electron beam io from the counting rate of the EDX detector on an element standard.
The cathode which generates the electrons shall be warmed until 61232-7 emissions are stable. However, devices with cold field emitters often show excessive levels of beam strength instability. 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 162322-7 the deflector lens varies from unit to unit and will be specified by the manufacturer of the system.
This means that elements having X-ray lines close together in the spectrum will isk better separated and a more accurate result will be obtained. This means that the electron beam is guided to a number of measuring 162332-7 over the particle during the EDX analysis. This reduces the risk which exists, when uso a measurement using only one point, that a non-homogeneity in the particle or a foreign substance adhering to it e.
Not ixo for correct particle analysis 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.
Particles which do not fit to any material class with regard to chemical composition shall be counted in a separate class e. On completion of a fully-automated analysis, automatic systems shall be able to find individual particles, analyze them manually and, where necessary, classify them afterwards.
In order to obtain further information regarding their 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 io be detected, but, because of their high carbon signals, 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. 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 influencing the imaging quality and accuracy of the particle measurement. If these factors cannot be controlled, appropriate measures shall be taken vibration absorbers, encapsulation, etc.
Good laboratory practices shall be observed in the preparation and use of these chemicals.
Follow the precautions for safe handling and usage as described in the MSDS available from 116232-7 supplier. Appropriate precautions should be taken to avoid inhalation of fumes from these solvents. Always use suitable protective equipment. An earthing strap shall be provided where there is a risk, especially for the vacuum equipment where often volatile liquids are involved.
In the event of spillage it shall be cleaned-up in the manner detailed in the MSDS. Pure element standards function as calibration substrates and this is described in ISO The calibration period depends upon the usage of the instrument, and the instrument manufacturer will advise on this.
However, for single shift application, a calibration period of one year is considered appropriate. It shall be re-calibrated if the EDX system has been repaired, serviced, or adjusted.
SERCOVAM, Tests laboratory, News, Cleanliness of components of fluid circuits
A validation procedure shall be developed and used periodically e. Additional or deviating points are described below. In this way, an X-ray spectrum range is available for the analyses which enables the clear separation of the spectral lines and thus of the elements. NOTE 1 In principle, all elements can also be detected using lower voltages of acceleration, e.
If done, these lines are very close to one another making a separation of the elements more difficult. These are mentioned in the documentation.
The higher the number of quanta detected, the more precise the analysis result will be. As a reference, a minimum of usable counting events per second cps are recommended, independent of the type of device used. For the same reason the analysis time per detected particle should not be less than one second. NOTE It is advisable that measurement is not started until both beam strength and vacuum have stabilized allow the cathode to warm up.
Table 1 — Example of a result with 6 material classes Size class? The analysed particles are grouped into material classes based on the isso of elements in their composition. See classification table in Annex A. This classification shall be agreed between parties. It presents the UK view on standards in Europe and at the international level.
It is incorporated by Royal Charter. Ieo British Standards are updated by amendment or revision. Users of British Standards should make sure that 162322-7 possess the latest amendments or editions.
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