Question 1

The figure below shows the copper-antimony Cu-Sb phase diagram.

Figure: copper-antimony Cu-Sb phase diagram

a) Find the chemical formula for the compound marked X (atomic weights of Cu and Sb are 63.54 and 121.75 respectively).

b) The Cu-Sb system contains 2 eutectics, 1 eutectoid, 1 peritectic and 1 peritectoid. Mark them all on the figure, write down the temperature and composition of each point, and identify the phases involved in each reaction, on cooling.

c) An alloy containing 53wt% Sb is cooled slowly to room temperature from the melt. Explain the phase changes that occur during cooling, using schematic sketches of the microstructure at key temperatures to illustrate your answer. Start writing down the unique data for weight percentage of Sb.

d) Sketch a temperature-time curve for the 95 wt% Sb alloy over the range 650 to 450oC and account for the shape of the curve.

Question 2

"To reduce wear on a steel component, a hard wear resistant ceramic coating is applied"

(a) Explain using suitable examples, what is meant by this statement.

why using ceramic coatings on steel

(b) With the aid of diagrams, illustrate three different techniques by which this could be done. Explain how a ceramic coating can be applied and discuss the advantages of the three techniques. You may use appropriate examples and references.