*3.2.3 Test conditions*

The sintering temperature was kept at 1123 K, as described in Section 3.2.1. This temperature made Cu-Sn system in liquid state so that liquid sintering was conducted for SBP8, SBP10, and SBP12. The mesh belt speed was set at 0.43 mm/s (first sintering) and 0.33 mm/s (second sintering). So, test specimens were maintained at 1123 K for 1050 s during the first sintering and for 1368 s during the second sintering. These sinterings were conducted under only reducing atmosphere (indicated as a after the materials in **Table 1**), only inert atmosphere (indicated as b after the materials in **Table 1**), and mixed atmosphere. Some tests were conducted using a complex procedure. They were sintered under inert gas during the first sintering and under reducing gas during the second sintering (indicated as c after the materials in **Table 1**). Under the reducing atmosphere, not only oxygen but also sulfur was able to reduce. Here, the reducing atmosphere was a mixture of H2 gas and N2 gas, and the inert atmosphere consisted only of N2 gas. Sulfur in bronze may react as H2S in the reducing gas. Thus, sintering under an inert atmosphere was also performed to compare the states of sulfur and sulfide bronze. Between the first and the second sinterings, a rolling process was performed, and the thickness of the bimetal was controlled to level the all surface of the Cu side of the bimetal contacted with the roll surface.
