1、 FORD LABORATORY TEST METHOD EU-BQ 010-01 Date Action Revisions 2000 11 09 Editorial no technical change A. Cockman 1994 02 28 Printed copies are uncontrolled Page 1 of 5 Copyright 2000, Ford Global Technologies, Inc. FILM THICKNESS MEASUREMENT FOR ANODIZED ALUMINUM Application This method describes
2、 the use of the light section microscope for the non - destructive measurement of anodised aluminum film thickness. Apparatus and Materials Required Zeiss Light Section Microscope This instrument has its design based upon the light section principle, and has been found to be adaptable to the measure
3、ment of thin film thicknesses of any transparent coating over both magnetic and non - magnetic surfaces. The basic light sectio n microscope unit (see drawing) consists of the following major components: A microscope with built - in illumination device, built -in measuring eyepiece and two pairs of
4、objectives for 200X and 400X total magnification respectively. A Stand with Stage Plate Mechanical Stage With Vee blocks for positioning relatively small test samples. Flat Glass Reference Surface A flat glass reference surface is required for proper alignment of the slit image. Dimensions approx 50
5、 x 50 mm and a minimum thickness of 0. 8 mm. Sample Holder A clamping device (or equivalent) compatible with the size and shape of the samples to be tested, which will facilitate positioning the test sample so that the test area is very nearly normal to the axis of the microscope. Conditioning and T
6、est Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/ - 2 C and 50 +/ - 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherw ise specified. FORD LABORATORY TEST METHOD EU-BQ 01
7、0-01 Page 2 of 5 Copyright 2000, Ford Global Technologies, Inc. Procedure A. Instrument Set-up 1. Place the instrument on a flat and relatively vibration - free surface. 2. Switch the power supply unit on by setting the knob provided to any mark between 1 and 8 on the graduated disc. This setting ma
8、y later be changed to obtain a desired level of illumination. B. Initial Focus and Alignment 1. Focus the cross lines, visible through the eyepiece, as outlined in the instrument manual (supplied by the manufacturer). 2. Place the flat glass reference su rface on the stage plate. The surface of this
9、 glass piece must be thoroughly clean (free of fingerprints, grease film, etc.). 3. Looking into the eyepiece, lower the microscope body by turning the vertical drive knob slowly, to obtain a well focused ligh t band. 4. This light band must be parallel to the horizontal portion of the cross - lines
10、. If it is not parallel, it must be aligned accordingly by means of the knob provided, as outlined in the instrument manual. Once this light band has been properly a ligned, the aligning knob should not be touched in the course of instrument operation. 5. By means of the vertical drive knob elevate
11、the microscope body to a safe clearing distance between objectives and stage plate. 6. Remove the glass reference surfac e from the stage plate. C. Selecting the Objectives 1. Select the 400X total magnification pair of objectives. At this level of magnification each division on the measuring drum i
12、s equivalent to 0.5 microns. Anodic film thicknesses up to 200 microns are easily measured at this magnification level. For measurements of thicker films, the 200X total magnification pair of objectives are used, in which case each division on the measuring drum will be equivalent to 1.0 microns. D.
13、 Coating Thickness Measurement 1. Clean the surface of the test sample thoroughly free of fingerprints, grease film, etc. 2. Place the test sample directly below the microscope objectives. A relatively small sample may be placed on the stage plate. For measurements on larger sam ples, the microscope
14、 body can be swiveled through 180 deg about its vertical axis. FORD LABORATORY TEST METHOD EU-BQ 010-01 Page 3 of 5 Copyright 2000, Ford Global Technologies, Inc. 3. Looking into the eyepiece, turn the focusing drive knob slowly, advancing the microscope toward the test area, until a focused three -
15、 lined image of the light band appea rs in the field of view. In some cases a four - lined image will appear in the field of view, particularly in the case of thicker coatings or smooth and good reflecting surfaces. This multiple - lined image will consist of essentially parallel or equidistant band
16、s: The first (from the bottom) adopting the profile of the top surface of the coating, and the second band adopting the surface profile of the coated surface. 4. Adjust the power supply unit knob to obtain the desired level of illumination. 5. In th e case of a flat test surface, the light bands sho
17、uld be essentially parallel to the horizontal cross -line, if the test area is properly positioned (normal to the axis of the microscope). See Figure 2. If these are not parallel, the test sample position must be altered accordingly. Care must be taken when adjusting the sample position, to avoid bu
18、mping the microscope objectives. 6. In the case of a curved test surface, these light bands will, of course, appear curved accordingly. Here the test area need s to be positioned so that the centre of curvature lies on the axis of the microscope (or an extension of it, depending on whether this curv
19、ature is concave or convex). This position is easily achieved by adjusting the sample position until a well - defined image similar to that in Figure 3 (or an inverted image of it, depending on the type of curvature) is visible in the field of view. 7. Disregarding the vertical portion of the cross
20、-lines visible in the eyepiece, set the horizontal portion at the third b and from the bottom and record the measuring drum setting. See first position of horizontal cross - line in Figures 2 and 3. 8. Turn the micrometer measuring drum to move the horizontal cross - line in the centre of the first
21、band (from the bottom), (second position of horizontal cross - line Figures 1 and 2) and record this measuring drum setting. Evaluation (400X total magnification) 1. Subtract the first reading from the second to obtain the instrument reading (divisions on the measuring drum). 2. Film t hickness (m)
22、= Instrument Reading 2 The standard deviation of the result is max +/ - 3 %. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining pro per use and handling in its facilities. FORD LABORATORY TEST METHOD EU-BQ 010-01 Page 4 of 5 Copyright 2000, Ford Global Technologies, Inc. FILM THICKNESS MEASUREMENT FOR ANODIZED ALUMINUM FORD LABORATORY TEST METHOD EU-BQ 010-01 Page 5 of 5 Copyright 2000, Ford Global Technologies, Inc. FILM THICKNESS MEASUREMENT FOR ANODIZED ALUMINUM
