Titanium ignition testing

FIG. 8—Typical Ignition test setup for titanium samples using tensile rupture. 

Heat of combustion, thermal conductivity, surface area and other factors influencing pyrophoricity of aluminium, cobalt, iron, magnesium and nickel powders are discussed [4], The relationship between heat of formation of the metal oxide and particle size of metals in pyrophoric powders is discussed for several metals and alloys including copper [5], Further work on the relationship of surface area and ignition temperature for copper, manganese and silicon [6], and for iron and titanium [7] was reported. The latter also includes a simple calorimetric test to determine ignition temperature. 

Two types of tests were developed for studying the ignition reactions in one, a thin metal disk was fractured either by gas pressure or by a plunger, while in the other, either a thin sheet or a 1/4-in. rod was broken in a tensile manner. In either test, both the composition and pressure of the atmosphere could be varied. With both types of tests, it proved to be surprisingly easy to initiate combustion of titanium. Ignition and complete consumption of both disks and rods occurred when titanium was ruptured, even at room temperature, in a high pressure of pure oxygen. 

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