In the Small ball Rebound Hardness eNM3A10tester, an alumina ball indenter with a diameter of

3mm and a mass of approximately0．056g is ejected at a velocity of V1＝10m／s. The rebound velocity V2of the ball indenter after impacting the sample is measured to obtain the rebound coefficient e ＝V2／V1, which is used as an index of rebound hardness. In general, in the rebound hardness test, the kinetic energy of the indenter impacting the specimen is constant, but the load due to the impact varies depending on the hardness of the specimen. We investigated experimentally that how much load is generated during the impact, using high-precision hardness reference blocks and a static hardness tester. It is confirmed that the impact load is greater for harder specimens and is less than

50kgf for metal specimens with hardness less than700HV. The estimated time of deformation is less

than0．1ms.

The author investigated the adhesion strength of tin solder with Langmuir-Brojett film and found that the strength is smaller than that of bare tin sample in case of carbon layer being formed on the solder/substate interface.