Questions help please

maniac2003

Hi Folks,
Really struggling would really appreciate if anyone can help with these please.

Q1: An X-ray diffraction analysis on a substance, with a cubic structure, gives an inter-planar
spacing (d) of 0.12nm and a lattice parameter (a) of 0.60nm. What is the plane?

Q2: Nickel has FCC crystal structure. If the angle of diffraction for the (220) set of planes occurs
at 16.57 degrees (first order) when monochromatic radiation with a wave length of 0.0711nm
is used; find the inter-planar spacing and the atomic radius.

q3: Calculate the number of vacancies in Nickel (per cubic meter) at 1050oC, 1250oC and
1450oC. The energy of formation of a vacancy is 1.4eV. You may assume density remains
constant with temperature.


Q4: What is the composition, in atomic percent, of an alloy that contains 50g Cu and 50g Ni.


Q5. Determine the carburising time necessary to achieve a carbon concentration of 0.5 wt.% at a
position 3 mm into an iron-carbon alloy that initially contains 0.06 wt.% carbon. The surface
concentration is to be maintained at 0.85 wt.% carbon, and the treatment is to be conducted at
1,000°C.
For C in γ-iron at 1,000°C, the pre-exponential coefficient is given by 2.3x10-5 m
2
/s, and the
activation energy is 148 kJ/mol.

Thanks in advance.
Maniac

zuutroy

Can only help with the first two:
1
d= a/sqrt(h^2+k^2+l^2)

so (h^2+k^2+l^2)= (a/d)^2 = 25. The only plane that satisfies this is the (500).

_______
2
lambda = 2 d sin(theta)
so d = lambda/2sin(theta)
When you have 'd' you can solve for 'a' using the equation in Q1.

For an FCC crystal there are 4 atomic radii across any face, which has a length of (sqrt2)*lattice constant

so a= 4r/sqrt(2)

maniac2003

zuutroy wrote: »

Can only help with the first two:
1
d= a/sqrt(h^2+k^2+l^2)

so (h^2+k^2+l^2)= (a/d)^2 = 25. The only plane that satisfies this is the (500).

_______
2
lambda = 2 d sin(theta)
so d = lambda/2sin(theta)
When you have 'd' you can solve for 'a' using the equation in Q1.

For an FCC crystal there are 4 atomic radii across any face, which has a length of (sqrt2)*lattice constant

so a= 4r/sqrt(2)

thank you so much really big help you've no idea