Roughness specimens

Fig. 5. Wedge test results for Ti adherends with several different surface treatments having differing degrees and. scales of roughness. Specimens were exposed to 100% relative humidity at 60 C. Data from Ref. 132. ...

Flat polished specimens are necessary, as X-rays will not be detected from regions of the specimen which are not in line-of-sight of the detector. Rough specimens would therefore give topographical effects which might be misinterpreted as variations in composition. 

A new type of cylinder-on-disk tribometer was developed that can measure friction accurately under conditions of boundary lubrication with varying velocity ranging from ultra-low (5pm/s) to moderate (17cm/s). An isotropic roughness specimen and an anisotropic roughness specimen were used to study the boundary lubrication performance of several lubricants. The primary conclusions at this stage of the study are as follows ... 

As shown in Fig. 7 in the proceedings, the effect of StA-formulation appeared in the region smaller than around A=10 when compared with the additive-free oils, for isotropic roughness specimen. This result seemed acceptable because StA performs its lubricity at the solid contact part. 

The specification ANSI/ASME B46.1 also provides guidance for a qualitative roughness comparison using the Microfinish Comparator. The Comparator consists of a series of flat-surface roughness specimens for visual and tactual surface roughness comparisons. It is another tool available in reverse engineering to verify the manufacturing process. 

The oxidation rate of pure Fe in Oj has been shown to be affected by specimen shape and the original surface profile . For iron oxidising in Oj, 50 50 O2 + HjO and O2 + COj rough surfaces have been found to oxidise more slowly than smooth surfaces, since surface irregularities hinder the oxide flow . The oxide is unable to deform sufficiently to maintain intimate contact with the metal surface such that porous scales are formed . 

Nature of the metal surface The critical concentration of an anion required to inhibit the corrosion of iron may increase with increasing surface roughness. Thus, Brasher and Mercer" showed that the minimum concentration of benzoate required to protect a grit-blasted steel surface was about 100 times greater than that required to protect an abraded surface. However, surface preparation had little effect on the critical inhibitive concentrations for chromate" or nitrite " The time of exposure of the iron surface to air after preparation and before immersion may also affect the ease of inhibition by anions. There is evidence """ that the inhibition by anions occurs more readily as the time of pre-exposure to air increases. Similarly, if an iron specimen is immersed for some time in a protective solution of an inhibitive anion, it may then be transferred without loss of inhibition to a solution of the anion containing much less than the critical inhibitive concentration . ... 

The aspect of sample preparation and characterization is usually hidden in the smallprint of articles and many details are often not mentioned at all. It is, however, a very crucial point, especially with surface and interface investigations since there might be many unknown parameters with respect to surface contaminations, surface conformations, built-in stresses, lateral sample inhomogeneities, roughness, interfacial contact etc. This is in particular important when surfaces and interfaces are investigated on a molecular scale where those effects may be quite pronounced. Thus special care has to be taken to prepare well defined and artifact free specimens, which is of course not always simple to check. Many of these points are areas of... 

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