pyrofuze


 

General Discussion of Pyrofuze®

PYROFUZE ® consists of two metallic elements in intimate contact with each other. When these two elements are brought to the initiating temperature, they alloy rapidly resulting in instant deflagration without support of oxygen. Initiation is by heat and heat alone. All that is required is the exposure of the composite to the proper minimum temperature. The trigger reaction will reach temperatures in excess of the boiling point of the constituents. Once started, the reaction will not stop until alloying is completed or the unalloyed composite is subjected to some form of massive cooling that overwhelms the composite so that it cannot reach minimum operating temperature. The reaction end products consist normally of tiny discreet particles of the alloy of the participating materials. The present PYROFUZE® composition was chosen for a number of desirable characteristics; it is a composite of alloys of Palladium and Aluminum. It is available in the following physical forms: Wire; and, Ribbon rolled from wire.

It cannot be overemphasized that the PYROFUZE® reaction is not of an explosive or pyrotechnic nature. The only energy released is thermal (approximate minimum reaction temperature 2800° C/5000° F, 325 calories per gram, 2890 calories per cubic centimeter). The minimum initiation temperature is 650° C/1200° F.

Wire

Chemical composition:

  • Outer Jacket
    • 5% Ruthenium
    • Balance Palladium
  • Inner Core
    • #5056 Aluminum

Ribbon

Ribbon can be fabricated from round wire. Maximum practical aspect ratio is 10:1; i.e. width to thickness

Calories per Foot of Selected Sizes of Pyrofuze® Wire

.001" 0.4 cal/ft.
.002" 1.4 cal/ft.
.003" 3.1 cal/ft.
.004" 5.8 cal/ft.
.005" 8.9 cal/ft.
.006" 13.2 cal/ft.
.007" 17.8 cal/ft.
.008" 23.4 cal/ft.
.009" 29.8 cal/ft.
.010" 37.1 cal/ft.
.012" 53.2 cal/ft.
.015" 83.5 cal/ft.
.020"

Threshold Ignition Currents & Other Data for Pyrofuze® Wire

Amperes to Ignite
Diameter (Inches) Milligrams per 20 CM Calculated Resistance/ft. at 25ºC Air Argon Vac.
.020 300.00 0.155 9.50 8.80 6.500
.015 169.00 0.275 6.90 6.00 4.100
.012 108.00 0.430 5.00 4.40 2.800
.010 75.00 0.620 4.00 3.50 2.200
.009 61.00 0.760 3.50 3.00 1.800
.008 48.00 0.970 3.00 2.70 1.500
.007 36.60 1.260 2.60 2.20 1.200
.006 27.00 1.720 2.10 1.85 0.900
.005 18.80 2.500 1.70 1.50 0.650
.004 12.00 3.860 1.30 1.15 0.430
.003 6.75 6.900 0.95 0.80 0.250
.002 3.00 15.500 0.60 0.50 0.100
.0015 1.69 27.500 0.45 0.35 0.060
.001 0.75 62.000 0.30 0.25 0.020
.0009 0.61 76.000 0.26 0.23 0.018