Describe the movement of powder particles during
compaction in powder-metallurgy process. What features are
responsible for the fact that powder does not flow and transmit
pressure like a liquid?
(a) Describe the steps in conventional powder metallurgy shaping
process. What are the advantages and disadvantages of this process?
(b) How does the fabrication of thermoplastic polymer differ from
the processing of thermosetting polymer? (c) What is the heat
affected zone in welding? Why preheating is sometime performed in
welding?
Why are the parts manufactured using powder metallurgy of near
net shape? For mixtures of dissimilar metal powders, explain how
(a) blending/mixing, and (b) compaction are carried out before
sintering. Explain how (i) blending/mixing and (ii) compaction
steps influence the (a) sintering step and (b) porosity development
in the processed part.
Some commercial drain cleaners contain a mixture of sodium
hydroxide and aluminum powder. When the mixture is poured down a
clogged drain, the following reaction occurs:
2NaOH(aq) + 2Al(s) + 6H2O(l) →
2NaAl(OH)4(aq) + 3H2(g)
The heat generated in this reaction helps melt away obstructions
such as grease, and the hydrogen gas released stirs up the solids
clogging the drain. Calculate the volume of H2 formed at
23°C and 1.00 atm if 3.12 g of Al are treated with an...
1. Some commercial drain cleaners contain a mixture of sodium
hydroxide and aluminum powder. When the mixture is poured down a
clogged drain, the following reaction occurs: 2NaOH(aq) + 2Al(s) +
6H2O(l) → 2NaAl(OH)4(aq) + 3H2(g) The heat generated in this
reaction helps melt away obstructions such as grease, and the
hydrogen gas released stirs up the solids clogging the drain.
Calculate the volume of H2 formed at 25.5°C and 1.00 atm if 3.75 g
of Al is treated with...