Abrasion Methods

For many substrates light abrasion of the surfaces to be bonded can allow the adhesive to key better than when a highly polished adherend is used. Extremely active surfaces, such as those produced immediately following abrasion, particularly where mild steel components are concerned, tend to have a better affinity for the adhesive. This technique, however, is not recommended for many aluminium adherends. 

As well as producing an active surface, abrasion pretreatments are intended  

Before the abrasion process starts, irrespective of the method used, the substrate should undergo at least one of the cleaning processes highlighted earlier. 

If the substrate to be pretreated (either metallic or plastic) is delicate or if other suitable, more controlled equipment is not available, the surfaces to be bonded can be pretreated using a suitable abrasive cloth (e.g. Scotchbrite ), a hand- or power-operated wire brush or water-proof abrasive paper. In this latter case, the abrasive particles bonded to the paper should, ideally, have a particle-size range of 125-315 p.m. 

When a more vigorous abrasion of the surface is required, or the component is robust enough to withstand such a technique, the use of air- or water-borne gritblasting is, generally, the best method of achieving these ends. Here the use of dry, clean compressed air and/or water is essential as is the prevention of contaminated abrading media coming into contact with the surface to be pretreated. 

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ASTM D1175, Uniform Abrasion Method (5000 cycles). 

The link between laboratory abrasion methods and road tests is now well established so that further research can concentrate on further elucidation of the basic underlying processes. This concerns particularly the interaction between filler systems and polymers, which is continuously expanding through both new polymers and new fillers. But now the link does not extend from a basic experiment to tire road testing. It can be limited to a laboratory abrasion testing method and suitable basic experiments. 

Why is the above modification to the standard abrasion method adopted ... 

Abrasive methods Use of greaseless or water-based binders for buffing or polishing SR ... 

In the light of the above, contact abrasion methods can be classified into ordinary, used for measurements at room temperature, and high temperature. Classed among abrasion resistance test methods at room temperature are the following Bohme s, Mindt s, Harvey s, McGee s, Blondel s, dry friction with balls, dry friction without balls, and Siever s method. 

Fig. 4.4.14. Hardness anisotropy of some minerals determined by the dynamic abrasion method ...

Sclerometer scratch and manual abrasion methods, considered impractical today because they involve tedious repetition of measurement to obtain the required mean, give values very close to Vickers hardness results. This... 

Comparative values of standards on old Mohs scale obtained by scratch and abrasion methods and by indentation methods compiled by Povarennykh (1963)... 

Hardness determined by j Hardness determined by inden-scratch and abrasion methods I tation methods... 

It is somewhat more difficult to relate dynamic abrasion methods to diamond indenter methods. Since the Scott tower is designed for abrasiveness tests with ceramic glazes, it is obvious that the attempts to correlate abrasiveness derived by this method with hardness, relied on test results for glazes. The hardness of glazes is similar to that of typical glasses, and... 

A special advantage of the dynamic abrasion method is the typically workshop character of action on the object under test, thus allowing direct estimation of the commercial use of the mineral or rock under test. 

The Bohme s disc method for petrochemical estimation of rocks now used appears to be equivalent to the dynamic abrasion method only for monolithic, monomineral rocks. For rocks softer than silica or those composed of minerals of distinct hardness, porous or partially weathered, no correlation is found between Bohme s method and Vickers hardness or any other hardness, and abrasive action on a surface 42-49 cm2 in area does not allow estimation of the structural and textural specificity of orientations in the rock under test. 

The dynamic abrasion method opens broad possibilities of strength estimation of faience lining tiles (Table 8.6, Fig. 8.5). One could reasonably expect that products, for which the hardness of the glazed side is low, lack a developed intermediate layer. This has actually been confirmed in microscope tests. Both the Japanese tile (DK) and the Kenyan tile manufactured on Japanese technology conspicuously lack the intermediate layer. The cited indicative tests provided a basis for employing the dynamic abrasion... 

Comparing the Scott tower abrasion method used for estimation of abrasion resistance of glazes on ceramic ware (A. Szymanski et al., 1969b) with the dynamic abrasion method, interesting preliminary results were obtained suggesting their comparability and a mutual linear relation. 

Niewiedzielski G., Sobczynska J., Szymanski A., 1973, Dmuchawa Mackensena w zasto-sowaniu do oznaczania metodq scierania dynamicznego roznych tworzyw ceramicz-nych (Mackensen blower applied to determination of various ceramic materials by dynamic abrasion method), Szklo i Ceramika, 2. 

Szymanski A., 1973, Okreslenie twardosci mineralow i skal naturalnych i syntetyeznych metod Scieralnosci dynamieznej (Hardness determination in minerals and natural and synthetic rocks by dynamic abrasiveness method), Pr. nauk. Inst. Chemii Nieorg., Wroclaw Technical University, Stud, i Mater., 3. 

Also used for hardness determination are impact abrasion and rattle methods. In impact abrasion methods (impact abrasion hardness), three abrasive techniques are used a freely falling abrasive grain flow—the Scott tower method (Fig. 4.4.3a and b), pressure abrasion—the Macken-sen-Zeiss blower method (Fig. 4.4.7), and ultrasonic drilling—the Sonic Mill method (Fig. 4.4.18). 

In the group of contact abrasion methods there are, however, some of considerable practical importance, which enable an estimation of hardness difficult to assess by other methods. 

As equivalent to the Mackensen air blower, ultrasonic devices can be used, specifically those manufactured by Rio Grande and Branson (Fig. 4.4.18). With a suitably chosen nozzle delivering the abrasive material and with the device scaled on Mohs standard hardness blocks, small surfaces can be tested by the point abrasion method using ultrasonic impact abrasion technique. The possibility of employing a fine-grained abrasive for this purpose allows substantial miniaturization of measurement, as compared with Mackensen s method. 

Regions of the CdTe layer 12 and the HgCdTe layer 14 not overlaying one of the recessed regions of the substrate are removed by an abrasion method. 

Although the mechanisms of polyimide/metal adhesion remain to be fundamentally elucidated, it is generally accepted that the interfacial diffusion of metallic entities into the polyamic acid plays a key role at the interface [156-158]. Two main theories have been reported explaining the adhesion of the Pl/metal bond chemical and mechanical bonding [159]. Initial work emphasized mechanical bonding and most efforts were dedicated to the physical roughening of the substrate by different abrasive methods as well as chemical treatments in order to improve metal to polyimide adhesion by increasing the metal surface area [156,160-164]. 

Similar surface abrasion processes can be applied on all thermosetting plastics. Mechanical abrasion methods consist of abrasion by fine sandpaper, carborundum or alumina abrasives, metal wools, or steel shot. The following surface treatment procedure is usually recommended for most thermosetting plastics ... 

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