Calculating the diffusivity of hydrogen through an alloy coating on a steel container


by mmoadi
Tags: alloy, coating, container, diffusivity, hydrogen, steel
mmoadi
mmoadi is offline
#1
Dec29-09, 12:06 PM
P: 157
1. The problem statement, all variables and given/known data

Constant for the diffusion of hydrogen through steel is D(steal) = 4 x 10^5 cm/s. They try to improve steel tanks for hydrogen storage by applying the coating based on TiAlN alloys. What is the diffusion coefficient Dp of such coating, if the permeability of hydrogen is reduced by 19,000 times? In this attempt the steel had a thickness of
d(steal) = 0.5 mm, and the thickness of the alloys was d(alloy)= 10 nm.

2. Relevant equations

s= 2Dt

3. The attempt at a solution

x= 19,000, D(steal) = 4 x 10^5 cm/s, s(steal)= 0.5 mm, s(alloy)= 10 nm, D(alloy)= ?

s(steal)= 2D(steal)t
s(steal) + s(alloy)= 2D(alloy)xt

s(steal)/ [s(steal) + s(alloy)]= 2D(steal)t/ 2D(alloy)xt
s(steal)/ [s(steal) + s(alloy)]= D(steal)/ D(alloy)x
D(alloy)= D(steal) [s(steal) + s(alloy)]/ s(steal)x
D(alloy)= 21.1 cm/s

Are my calculations correct?

Thank you for helping!
Phys.Org News Partner Science news on Phys.org
Better thermal-imaging lens from waste sulfur
Hackathon team's GoogolPlex gives Siri extra powers
Bright points in Sun's atmosphere mark patterns deep in its interior

Register to reply

Related Discussions
Calculating the diffusivity of hydrogen through an alloy coating on a steel container Introductory Physics Homework 0
Selecting the appropriate carbon steel alloy Materials & Chemical Engineering 0
Estimating Diffusivity of Freon using known Diffusivity of Methane Materials & Chemical Engineering 1