Mechanical Alloying Preparation Of Gold-tin Alloy

Due to the excellent performance, high reliability, Au80Sn eutectic alloy solder is the general welding material of a variety of electronic apparatuses with high reliability. But the traditional eutectic Au80Sn alloy(mass ratio) prepared by casting is composed ofζ, phase(Au5Sn) and theδphase (AuSn) at room temperature, showing great brittleness. Such eutectic alloy can not be processed into foils which could meet the requirement though conventional methods. The multilayer composite rolling technology which the domestic focuses on will decrease the weld property owing to the difficulties in the accurate control of the reaction volume of gold and tin.In this paper, the high-energy ball milling was used in preparing Au80Sn alloy. Lieutenant General experimental eutectic composition of the single quality Au and Sn powder Add milling tank for milling. Through powder and ball fiercely impact collisions, powder repeated deformation, fracture, soldering, Powder lead to the proliferation of atomic particles, thus obtaining the alloy powder. Milling parameters of the control, can be controlled milling process is the formation of brittle and thus control of the powder composition. Study found that the longer the time milling, mixed powder brittle in the middle phase Au5Sn AuSn and the higher purity of the content. The results of XRD show that intermetallic phasesε(AuSn2),δ(AuSn) andζ'(Au5Sn) appear successively. The appearance order of intermetallie phases is related to thedegree of alloying. SEM and EDX observations show that with the increasing of milling time, the alloying of Aupowder and the Sn powder is fully completed, the density of the river—shaped deformation zones is gradually decreased, the homogeneity of the microstructures is increased, and the homogeneous eutectic alloy is obtained. The powder mixed with suppressed under low temperature (190℃) vacuum sintering, we still have good ductility.The experimental results show that high-energy ball milling prepared tin alloy solder is a workable approach, To Au-Sn alloy solder preparation for a new approach, and because in full accordance with eutectic composition ingredients,thus fully realized the true Au-Sn alloy chemical than for the preparation of high-quality Au-Sn alloy solder to provide a guarantee.