5. A sheet of BCC iron 1 mm thick was exposed to a carburizing gas atmosphere on one side and a decarburizing atmosphere on the other side at 725 °C. After reaching steady state, the iron was quickly cooled to room temperature . The carbon concentrations at the two surfaces of the sheet were determined to be 0.012 and 0.0075 wt %. Compute the diffusion coefficient if the diffusion flux is 1.5 x 10 -3 kg/ m2 s. The density for carbon and iron is 2.25 and 7.87 g/cm 3, respectively

5. A sheet of BCC iron 1 mm thick was exposed to a carburizing gas atmosphere on one side and a decarburizing atmosphere on the other side at 725 °C. After reaching steady state, the iron was quickly cooled to room temperature . The carbon concentrations at the two surfaces of the sheet were determined to be 0.012 and 0.0075 wt %. Compute the diffusion coefficient if the diffusion flux is 1.5 x 10 -3 kg/ m2 s. The density for carbon and iron is 2.25 and 7.87 g/cm 3, respectively

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter2: Electrical Components And Circuits

Section: Chapter Questions

Problem 2.4QAP

See similar textbooks

Similar questions

A monolayer of CO molecules is adsorbed on the surface of 1.00 g of an Fe/AI2O3 catalyst at 77 K, the boiling point of liquid nitrogen. Upon warming, the carbon monoxide occupies 4.25 cm3 at O oC and 1.00 bar. What is the surface area of the catalyst?
Compute the volume percent of graphite VGr in a 3.8 wt% C cast iron, assuming that all the carbon exists as the graphite phase. Assume densities of 7.9 and 2.3 g/cm3 for ferrite and graphite, respectively. Answer in Vol%
A mixture of He and N2 gas is contained in a tube at 298 K and 101.32 kPa total pressure. At one point the partial pressure of He is pA1=60.79 kPa and at a point 0.25 m distance away, pA2=20.26 kPa. If the total pressure is constant throughout the tube, calculate the flux of He at steady state if DAB of the He-N2 mixture is 0.687x10-4 m2/s.
A monolayer of N2 molecules is adsorbed on the surface of 1.00 g of an Fe/Al2O3 catalyst at 77 K, the boiling point of liquid nitrogen. Upon warming, the nitrogen occupies 3.86 cm3 at 0 °C and 760 Torr. What is the surface area of the catalyst? Use the value of the collision cross-section for N2 (from the Resource section) as an estimate for the area of a molecule.
Chromium is diffused into steel at 980o C to increase its corrosion resistance. If during the diffusion the surface concentration of chromium is maintained constant, how long will it take to achieve 1.8% of the surface concentration at a depth of 0.002 cm below the steel surface? Express your answer in seconds. The diffusivity has a pre-exponential term equal to 0.54 cm2/s and an activation energy of 286 kJ/mole.
Show solution : if 12m³ of nitrogen at constant temp of 30°c and 12kpa abs is permitted to expand to 30m³, what is the resulting pressure? Ans. 50 kpa
Calculate the diffusion constant of argon at 20 °C and (i) 1.00 Pa, (ii) 100 kPa, (iii) 10.0 MPa; take σ = 0.36 nm2. If a pressure gradient of 1.0 bar m−1 is established in a pipe, what is the flow of gas due to diffusion at each pressure?
Fabrication of a pre-stressed multi-layered diefor hydro-extrusion requires fitting of a tungstencylinder with 50.00mm diameter into a thick ring of stainless steel 316with internal diameter 49.94mm. To what temperature must the die components be heated for the cylinderto just fit into the hole?The thermal expansion coefficients for tungsten and steel 316 are a(W) = 4.5 *10^(-6)(°C)^(-1) and a(316 steel) = 16.0 *10^(-6)(°C)^(-1)
A solid surface with dimension 2.5 mm x 3.0 mm is exposed to argon gas at 90 Pa and 500 K. Calculate the (a) collision frequency and (b) number of collisions in 10 s.
The layer thicknesses are L1, L2 = 0.6L1, and L3 = 0.5L1. The thermal conductivities are k1, k2=0.6k1 and k3= 0.9k1. The temperatures at the left side and right side of the wall are TH=30OC and TC= -15OC, respectively. Thermal conduction is steady.What is the temperature difference ΔT2 across layer 2(between the left and right sides of the layer)?
What pressure of nitrogen gas is required to produce a collision rate of 5.00 × 1019 s−1 at 525 K on a circular patch of surface of diameter 2.0 mm?
In a study of the catalytic properties of a titanium surface it was necessary to maintain the surface free from contamination. Calculate the collision frequency per square centimetre of surface made by O2 molecules at 300 K and (a) 100 kPa, (b) 1.00 Pa. Estimate the number of collisions made with a single surface atom in each second. The conclusions underline the importance of working at very low pressures (much lower than 1 Pa, in fact) in order to study the properties of uncontaminated surfaces. Take the nearest neighbour distance as 291 pm.