Boron Impurity Elements In Aluminum And Its Effect On Conductivity

In order to eliminate the dispute on the mechanism that boron improves the conductivity of the aluminium conductor and further perfect the theories that boron interacts with impurity elements in the aluminium. The resistivity measurement of the aluminium conductor, microstructure observation through the optical microscope and SEM, phase composition analysis through the SEM and EPMA were adopted in the lab. On the basis of these , the action of boron on the conductivity of aluminium conductor was studied from three aspects as following.(1) Studied the action that boron interacts with the basic impurity elements Fe or Si and the effect of boron on the electric conductivity. The method of adding single impurity elements to high purity aluminium was used in the lab. Effects of boron on the conductivity of conductor aluminium containing Fe or Si have been investigated, under the situation of existing single element Fe or Si in aluminium. The results show that the conductivity of aluminium containing Si went up lightly when boron was put in; as same as it being put in pure aluminium; however the conductivity of aluminium containing Fe decreased distinctly by adding boron; and boron also changed the existing form and distribution of Fe in aluminum.(2) Studied the interaction of the boron with the slight impurity elements Cr> Mn or Ti and the effects of boron on the electric conductivity. Cr and Mn are two disputable elements , to this day , there is no unified understanding whether boron can interact with Cr and Mn. Yet, Ti is the generally acknowledged function target of the boron . Effects of boron on the conductivity of conductor aluminium containing TK Mn or Cr have been investigated, under the situation of existing single element Ti, Mn or Cr in aluminium. The results show that the conductivity of aluminium containing Mn decreased indistinctly when boron was put in; however the conductivity of aluminium containing Ti or Cr decreased distinctly by adding boron, at the same time, the results also show that boron didn't change the morphology pattern of this three kinds of aluminium containing impurity elements, but affected the content of the impurity elements in the parent aluminium differently.(3) Studied the compound effect that boron and rare-earth improved the electric conductivity. The double treatment process that boron and rare-earth were put in the aluminium containing Si with various content in different turn was implemented. Studied the variation of the conductivity when the single treatment process or the double treatment process was adopted . The results show that the effects that boron and rare-earth improved the electric conductivity weren't compound in spite of the content of Si and the turn in which boron and rare-earth was put in the aluminium , but, after the outgrowth in the first treatment was removed, the effects of the two treatment processes on the electric conductivity were compound, when analyzing the microstructure of the sample settling, the LaBa compound was found in the lab. It showed the interaction of boron and rare-earth weakened the capability gathering impurity elements each other. So the effects of boron and rare-earth onIIthe electric conductivity weren't compound , when the boron and rare-earth were put in the aluminium without removing the mid-outgrowth.