From figure 3, it can be seen that as the percent of HNBR in the composite increases, the adhesion to metal surface increases; however, as the HNBR percentage in the blend exceeds 30%, it causes cohesive failure
of the composite.
occurs when fracture appears within either the ink or adhesive if the system experiences an external force of sufficient intensity.
In the field of paints, coatings, rubbers and plastics, LPD has dealt with materials failure investigations, embrittlement and leaching issues, degradation and polymer swelling, adhesive and cohesive failure
, interfacial contamination, depolymerisation, paint delamination problems, wetting and mixing issues, amongst others.
The cohesive failure
is crack initiation and propagation inside adhesives, which occur within the adhesion layers.
The adhesion failure may be the result of poor surface preparation, a weak boundary layer, or cohesive failure
within the coating or substrate.
These factors, coupled with higher peak reflow temperatures used for Pb-free assemblies, could transfer more strain to the PCB dielectric structure, causing a cohesive failure
underneath the BGA corner pads.
Material may fail by delamination, cohesive failure
, propagation of crazing and material degradation.
Parallel to the fiber direction, the cohesive wood failure mainly occurs over the earlywood, whereas over the latewood the dominating failure types are wood-coating interphase failure and cohesive failure
between the coating layers.
All samples bonded with both showed cohesive failure
rather than breaking cleanly at the joint between the two materials.
of electroless copper deposit whereby the deposit actually separates from itself (Type 3).
At low rates, one predicts cohesive failure
with a peel force that rises with peeling speed.
an adhesive failure if no TPE residue is left on the substrate, or a cohesive failure
if the failure is in the TPE.