**2. Chemical component of sulfide-dispersed bronze**

As shown in **Figure 1**, a phase diagram was calculated based on the calculation of phase diagrams (CALPHAD) method [6] of the Cu-Sn-Fe-S system in order to confirm the optimum content of the sulfide in the cast material. In the Cu-Sn alloy, since the crystallization of the α′ phase of Fe was suppressed, the Fe content was 1.3 mass% or less. The reason why the sulfide was dispersed in the Cu alloy is that crystallization of the sulfide (0.25 mass% or less) occurred after crystallization of the α-phase Cu. On the one hand, the sulfide in the matrix remained below 0.60% by mass experimentally. **Figure 2** shows the matrix and sulfides of casting alloys [7].

On the other hand, much amount of sulfide is able to disperse in the atomized bronze powders. Because of the rapid cooling of (gas and/or water) atomization, atomized bronze keeps their metastable state including sulfide.

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*Effects of Dispersed Sulfides in Bronze During Sintering DOI: http://dx.doi.org/10.5772/intechopen.86385*

**3. Sintering process of sulfide bronze as bimetal**

ness is evaluated as one of the mechanical properties.

oped as the sliding member described below.

*Microstructure of sulfide bronze of castings.*

**3.1 Materials**

**Figure 2.**

premixed material.

shown in **Figure 1**.

**3.2 Experimental method**

*3.2.1 Sintering and manufacturing process*

In this chapter, one of the conditions is the proposal of the copper alloy devel-

In the case of a Cu alloy containing a sulfide, sulfur may disappear from the Cu alloy by reacting with the reducing gas. Further, in the case of Cu-Sn-S, the mechanical properties of the sintered body have not been clarified. Therefore, hard-

Atomized powders were prepared for comparison of sintering properties. As a feature of the sulfide-dispersed Cu-Sn system materials, the sulfide was pre-alloyed by water atomization manufacturing. As shown in **Figure 3a–e**, micro-sized small dots were observed by scanning electron microscopy (SEM). This image is a sectional view of one of the typically sintered bronze-containing sulfides (from irregular powders). Generally, sintered composite from premixed bronze and sulfides indicated lower mechanical properties. It was reported that mechanical properties become better to cover the MoS2 particles by copper [8]. However, this sulfide-dispersed bronze was made by atomizing as pre-alloyed material. So we can see that the pre-alloyed material shows better mechanical properties than the

Energy-dispersive X-ray spectroscopy (EDS) was performed to determine the elements that make up the observed small dots. As a result, as shown in **Figure 1**, a ternary sulfide consisting of Cu, Fe, and S was detected. This sulfide is a kind of bornite (Cu5FeS4) detected by the X-ray diffraction (XRD) method [9] as shown in **Figure 4**. Only a small peak was observed as bornite (dot references). It may be metastable in the system because it is difficult to crystalize in the phase diagram as

By preparing, bimetal specimens, these procedures are conducted as below. At first, powder was sprayed to a height of 1.0 mm (by leveling off) onto a 3.2-mm-thick steel plate (low-carbon steel). At this time, binding materials such

**Figure 1.** *Calculated phase diagram of sulfide bronze [7].*

*Effects of Dispersed Sulfides in Bronze During Sintering DOI: http://dx.doi.org/10.5772/intechopen.86385*

**Figure 2.** *Microstructure of sulfide bronze of castings.*
