A permeation cell was used to measure rates of H permeation through arc-cast material of better than 3N-purity. The permeation was measured at temperatures ranging from 1300 to 2600C, and at H pressure differentials of 1 and 0.1atm; across isothermal W membranes (table 195). The H permeation rates were almost proportional to the square root of the pressure, were inversely proportional to the membrane thickness, and obeyed:

P (cm mm/min atm½) = 33.2 exp[-33.0(kcal/mol)/RT]

E.A.Aitken, H.C.Brassfield, P.K.Conn, E.C.Duderstadt: Transactions of the Metallurgical Society of AIME, 1967, 239[10], 1565-74

 

Table 195

Permeation of H through Arc-Cast W

 

T (C)

Pressure Gradient (atm)

P (cm mm/min atm½)

1300

1

0.0013

1500

1

0.0023-0.0033

1500

0.1

0.00094-0.0031

1540

1

0.0032

1540

0.1

0.0038

1800

1

0.010-0.012

1840

1

0.011

1840

0.1

0.010

2000

1

0.021-0.025

2000

0.1

0.021-0.022

2040

1

0.024

2200

1

0.033-0.043

2200

0.1

0.041

2240

1

0.042

2240

0.1

0.042

2400

1

0.054-0.071

2400

0.1

0.052-0.071

2440

1

0.070

2500

1

0.064-0.088

2500

0.1

0.063-0.086

2600

1

0.078-0.11

2600

0.1

0.071-0.11