reversible interconnection

提出了一种可逆互连的新概念，即任何材料组合都可以可逆地结合和分离。从回收材料的角度来看，无机材料的分离也很重要。然而，很少有人尝试设计可以根据场合需要分离的材料互连。为了证明可逆互连的概念，研究了两种分离技术：通过反应产物的形成削弱键合界面和ii)由氢吸收引起的内部应变。第一种情况是通过多晶铝与不锈钢的界面来证明。由于工艺温度高，在键合过程中会形成脆性反应层，采用扩散键合等常规方法很难进行键合。在室温下，通过表面活化键合（SAB）成功地进行了连接。在键合过程中，表面在真空中被离子或原子束照射激活，然后彼此接触。接头抗拉强度高达20 Mpa。在823K温度下加热7.2ksec，界面析出Al_<76>Fe_<24>, Al_5Fe_2 FeAl_2。因此，在不施加任何机械外力的情况下，接头可以在界面处分离。第二种分离技术是多晶Cu-、Al-LaNi_<4.5>Al_<0.5>接头。同样在这种情况下，由于传统的键合过程的高温可能导致储氢合金的降解，因此在室温下由SAB进行键合。将接头暴露在20 ~ 50atm的氢气气氛中后，可以观察到接头在键合界面处的分离。

A new concept of reversible interconnection is proposed, by which any material combination can be bonded and separated reversibly. Separation of inorganic materials is important also from the point of view of recycling the materials. Few attempt, however, has been made for designing materials interconnections which can be separated as occasion demands. To demonstrate the concept of the reversible interconnection, two techniques of separation were investigated : weakening bonded interface i) by formation of reaction products and ii) by internal strain induced by hydrogen absorption.The first case is demonstrated by polycrystalline Al and stainless steel interface. It is difficult to bond them by the conventional technique like diffusion bonding, because a brittle reaction layr is formed during the bonding due to the high process temperature. Their joining was carried out successfully by means of the surface activated bonding (SAB) at room temperature. In the bonding procedure, the surfaces are activated by ion or atom beam irradiation in vacuum and then brought into contact to each other. The tensile strength of the joint reaches as high as 20 Mpa. By heating the joint at 823K for 7.2ksec, Al_<76>Fe_<24>, Al_5Fe_2 FeAl_2 were precipitated at the interface. As a result, the joint could be separated at the interface without applying any external mechanical force. The separation occurred between the reaction layr and Al.The second separation technique is demonstrated by polycrystalline Cu-, and Al-LaNi_<4.5>Al_<0.5> joint. Also in this case, the bonding is performed by the SAB at room temperature, since degradation of the hydrogen storage alloy might be caused by high temperature of the conventional bonding process. After exposing the joint to hydrogen atmosphere of 20-50atm, separation of the joint at the bonded interface could be observed.