Proposal for a hardness measurement technique without indentor by gas-cluster-beam bombardment

Large gas-cluster-ion bombardment has been shown to be a unique tool for ge nerating a variety of bombarding effects over a broad range of acceleration energies. A hardness measurement technique is proposed in this paper based on the use of the effect of crater formation by large gas-cluster beams. T he cluster impact leaves a hemispherical crater on a surface, the size of w hich varies with surface hardness and cluster parameters (which can be pred etermined). As shown in this paper, the crater depth h (or diameter d) and Brinell hardness B are correlated through the formula h similar to(E/B)(1/3 ), where E is the cluster acceleration energy. The material hardness, bindi ng energy, and the crater size have also been correlated with the sputterin g yield Y, and hence this correlation can also be experimentally applied fo r measuring hardness. The proposed method is based entirely on surface effe cts which depend only on the surface material and not on the substrate and therefore should be particularly suitable for measuring hardness of thin de posited films. This technique also eliminates the need for indenters that a re harder than the material measured.