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本文在超高真空(10~(-7)Pa)条件下量测了Nb-Nb(110)、Nb-Ta(110)、Nb-W(110)及Nb-Ti4个粘附对的粘附力,并从接触表面形貌的角度求得了真实接触面积,进而得到了各粘附对间的粘附强度,结果与采用简单紧束缚自洽矩方法计算所得理论结果一致。研究表明,超高真空下过渡金属间存在一种相互作用——由两金属间共用电子引起的化学键,而且主要由其外层d电子态密度所决定。过渡金属Nb与Nb、Ta、W、Ti之间粘附强度的实测值介于每对原子0.2～2.0eV之间。当样品受热升温后,由于C、N、B、S等少量非金属杂质的表面偏析致使粘附强度明显降低。
In this paper, the adhesion of Nb-Nb (110), Nb-Ta (110), Nb-W (110) and Nb-Ti four adhesion pairs was measured under ultrahigh vacuum (10-7 Pa) The contact area was obtained from the contact surface topography, and the adhesion strength between each adhesion pair was obtained. The results were in good agreement with the theoretical results calculated by the simple tight bound self-consistent method. Studies have shown that there is an interaction between transition metals under ultra-high vacuum - a chemical bond caused by the sharing of electrons between the two metals, and is mainly determined by the d state density of the outer layer. The measured values of the adhesion strength between the transition metal Nb and Nb, Ta, W, Ti ranged from 0.2 to 2.0 eV per pair of atoms. When the sample is heated up, the adhesion strength is obviously decreased due to surface segregation of a small amount of non-metallic impurities such as C, N, B, S and the like.