Laugier, "Comparison between nanoindentation and scratch test hardness (scratch hardness
) values of copper thin films on oxidised silicon substrates," Surface and Coatings Technology, vol.
Based on the American Society for Testing Materials (ASTM) , scratch hardness
([H.sub.s]) is defined as "the normal load of the stylus over the load-bearing area".
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.
. Scratch hardness
was carried out as per ASTM D-2197.
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.sub.i]/ [square root of (term)]A (the Cartesian coordinate system is shown in Fig.
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
IPC-4781, Table 3-1, Requirements of Qualification Requirement for Marking Type Requirement Type 1 Permanent No Type 3 Semi- Type 4 Permanent Electrical Permanent Temporary Direct Metal Metal Contact Contact Physical Hardness Yes Yes Yes No Adhesion to Yes Yes Yes AABUS * Solder Mask Materials Conformal AABUS AABUS AABUS No Coating Adhesion Flammability Yes Yes Yes No FTIR Yes Yes Yes Yes Environmental AABUS AABUS AABUS AABUS Compliance Testing and Inspection Requirement Paragraph IPC-TM-650 Other Test Methods Method Hardness 3.5.1 None ASTM D3363, Scratch Hardness
Test Adhesion to Solder 220.127.116.11 18.104.22.168 - Mask Materials Conformal Coating None AABUS Adhesion Flammability 3.6.3 None UL94 FTIR 22.214.171.124 None - Environmental 3.12 None - Compliance * AABUS: As agreed between user Table 2.
is the resistance to scratching by a pointed tool drawn across the coating with a controlled velocity.
It has a Mohs scratch hardness
of 7.5-8, which is exceeded by only a few other gemstones such as chrysoberyl at 8.5, ruby and sapphire corundum at 9, and diamond at 10.