*5.2.1 Microstructural analysis*

Needle shaped Zn phase and leaf shaped Aluminium phase are equally distributed in the microstructure. with the former contributing to increase in strength of the alloy. In the first alloy, the chemical composition of the needle- and leaf-shaped morphologies is given as follows: Leaf-shaped morphology (Al, 88%; Zn, 12%) and needle-shaped morphology (In, 72%; Zn, 27.96%; and Sn, 0.02%). In the second alloy, composition of the leaf- and needle-shaped morphologies is given as follows:

**Figure 9.** *Examination on leaf shape of the specimen.*

**17**

**Figure 13.**

*Role of Intermetallics in Lead-Free Alloys DOI: http://dx.doi.org/10.5772/intechopen.85515*

*Examination on leaf shape of the specimen.*

Leaf-shaped morphology (Al, 91.6%; Zn, 8.4%) and needle-shaped morphology

EDAX analysis for both the alloys is presented in **Figures 13–16**. In both cases, the leaf-shaped morphology showed no intermetallics, whereas the needle-shaped

Rod-like zinc-rich phases have been observed when cerium and lanthanum of the order of 0.1 wt.% are added [18]. In the current work, since the weight % of rare earth element indium added is relatively high, in all probability, the needle-like phase is rich in indium (72 and 66.36%, respectively) and zinc percentage is lesser,

(In, 66.36%; Zn, 31%; and Sn, 2.64%) (**Figures 9–12**).

*5.2.2 EDAX analysis*

**Figure 11.**

**Figure 12.**

morphology showed intermetallics.

*Chemical composition of the leaf-shaped specimen-alloy 1.*

*Examination on needle shape of the specimen.*

**Figure 10.** *Examination on needle shape of the specimen.*

*Role of Intermetallics in Lead-Free Alloys DOI: http://dx.doi.org/10.5772/intechopen.85515*

*Lead Free Solders*

**Figure 8.**

*Spectrum 10 EDAX graph.*

It is seen that 1.91% sigma phase is present in the Zn peak, whereas the indium peak, which occurs as two small peaks in the tin cluster, shows 0.20% sigma phase. **Figures 7** and **8** show the microstructure and EDAX at another location. Here, sigma phase is 1.50% in the Zn peak and 0.55% in the aluminium peak. Indium

Similar results on the microstructure and EDAX analysis of 87Sn**▬**7Zn**▬**3Al**▬**3In

Needle shaped Zn phase and leaf shaped Aluminium phase are equally distributed in the microstructure. with the former contributing to increase in strength of the alloy. In the first alloy, the chemical composition of the needle- and leaf-shaped morphologies is given as follows: Leaf-shaped morphology (Al, 88%; Zn, 12%) and needle-shaped morphology (In, 72%; Zn, 27.96%; and Sn, 0.02%). In the second alloy, composition of the leaf- and needle-shaped morphologies is given as follows:

and 87.5Sn**▬**6Zn**▬**2Al**▬**2.5 in lead-free soldering alloys are presented below.

peaks show 0.1% sigma and 1.425 sigma, respectively.

**5.2 Analysis of high Al-high indium alloys**

*5.2.1 Microstructural analysis*

*Examination on leaf shape of the specimen.*

*Examination on needle shape of the specimen.*

**16**

**Figure 10.**

**Figure 9.**

**Figure 11.** *Examination on leaf shape of the specimen.*

**Figure 12.** *Examination on needle shape of the specimen.*

Leaf-shaped morphology (Al, 91.6%; Zn, 8.4%) and needle-shaped morphology (In, 66.36%; Zn, 31%; and Sn, 2.64%) (**Figures 9–12**).
