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The increasing trend in the scratch hardness
values can be attributed to the improvement in the adhesion between composite coating and metal substrate.
Pencil and scratch hardness
of the coating was measured on hardness tester according to ASTM D 3363 and IS-104 respectively.
Consequently, the normal and tangential scratch hardness
as well as the ratio h/ [square root of (term)]A are constant during the loading sequence of a scratch test on homogeneous materials and stresses and strains are functions of the dimensionless variables [x.
The solutions prepared were applied by brush on clean mild steel panels of 15cmx 15cm for evaluating drying time, tin panels of the size 15x15cm for flexibility and adhesion, scratch hardness
and impact resistance and glass panels of the size 15x15cm for water, alkali and solvent resistance.
The scratch hardness
is analogous to the indentation hardness given by Briscoe , as the normal load Fn divided by the contact area, which for a spherical indenter is the area of a circle with the diameter equal to the width of the scratch track d
1 None ASTM D3363, Scratch Hardness
Test Adhesion to Solder 3.
is the resistance to scratching by a pointed tool drawn across the coating with a controlled velocity.
The process results in cores produced with good scratch hardness
, high strength and excellent permeability.
The cured film samples were used for the determination of mechanical properties such as adhesion, flexibility, scratch hardness
, gloss, and impact resistance; these cured film samples were also used to observe the effect of various chemicals and solvents (chemical resistance properties) such as sulfuric acid, acetic acid, sodium hydroxide, sodium carbonate and methanol, methyl ethyl ketone, xylene, and deionized water, respectively, on the surface of the film.
of the dry film was measured by using a scratch tester, model number 705 (Sheen instrument) with stylus accessory and a travel speed of 0.