Mound Laboratories has been investigating pyrotechnic materials for several years. Prior studies on the mechanism of ignition have been performed on Ti/KCIO, and Ti/ZB mixtures. Tbese studies have shown the importance of the surface oxides of these materials in determining the mechanism of ignition. In the present study, XPS spectra of fused metal, oxidized fused boron and boron metal powder have been recorded. The spectra are interpeted by including the presence of a continuous boron suboxide layer. The results presented here are different from those previously reported, which suggests that the formation of boron oxide occurs in islets. The predominant suboxide will be shown to be B,O,, where x/y = 3. This oxide was found to be present independent of the degree of oxidation. Including this oxide in thickness calculations shows the oxidation of powders to be five layers or so thick, and also aids in understanding Ti/ZB ignition.
Titanium-boron pyrotechnic reactions are essentially gasless, are very exothermic, and are known to initiate only at extremely high temperatures. The reactants are stable in normal laboratory environments and require no special sample handling, such as inert storage. These factors make the titaniundboron mixture ideal for one-shot thermal heat source applications. Mound has been investigating energetic material ignition properties for a number of years. Pyrotechnic mixtures of TiH,/KCIO, have revealed that the surface composition of the titanium fuel was TiO, and its presence on the fuel's surface controls the TiH, + KCIO, reaction. In the present study the surface chemistry of titanium and of boron have been examined before ignition. To understand the effect of temperature on the reactants and the mixture, titanium powder, boron powder, and blends were analyzed at ambient and elevated temperatures. XPS, TG and DTA results presented will show that the oxide on boron is the controlling factor in the ignition mechanism of the titanium-boron pyrotechnic reaction.
Palladium metal powders used for hydrogen isotope pumping were studied for their bulk and surface chemistry changes during cleaning with hydrogen gas at 150 O C . Cleaning is necessary to promote rapid hydriding and dehydriding and to prevent contaminant ingrowth in the process gas during use. These studies show that heating the powders in vacuum at moderate temperatures (15OOC) in a reducing environment removes surface oxide, leaves a predominately palladium metal surface which presents no significant barrier to hydrogen absorption or desorption, and shows no loss in surface area and pourability. A surface model of PdO is given and XPS results show that the water-forming reaction is the mode of PdO reduction. Thermodynamic data are discussed which support the above results.
Polyetheretherketone (PEEK) is a relatively new high temperature engineering thermoplastic. The stability of neat and fiberglass reinforced PEEK towards air, KClO,, and TiHl 6s/KC104 blend was studied by the surface sensitive technique of X-ray photoelectron spectroscopy (XPS) and bulk technique of thermogravimetric (TG) analysis. Both of these examinations revealed no oxidation in the presence of air or Kclo, at temperatures of 60 or 120°C. In addition, no reduction of PEEK was observed in the presence of a reducing agent such as TiH1.65. The TG results also showed no air oxidation between 120 and 500°C.
have been successfully derncrsbted for this application include weml nickel-based alloys a d a family of Al-contahixg austenitic stainless steels. Seals made between a l i t~a -alumha-silica (US) glass-cezdc and nickel-based allays shm excessive metal attzck by the glass. This is also & m of the Al-containing alloys but the etching action of the glass is less severe. This attack w i l l muse reactions to cccur a t the glass-Ceramic/mw interface.:lot a l l reactions a r e detrimental to t h e seal, but same are and these unwanted reactions can muse the formation of pores and the subsequent loss of hemeticity. In t h i s paper, IAS glass-ceramic w i l l be Sealed to Al-containing alloys that were first oxidized prior t o sealing&led 'preoxidation'. Results w i l l be given that shm 'preoxi.dationl of the alloys -stantially reces the prcbability of glass/metal reactions during seal formation. The reduction in tke amcunt of reaction prcducts t h a t are created improves the o~e r a l l c p d i t y or' the interface without loss of seal bond strength. In addition, the mecham 'sn of surface oxide formation on these Al-containing steels is discussed. Auger data are presented that shm the canpsition of L\e result% oxides t o be a function of the oxidation temperature. =.ere are 3 7 0 theories that e x i s t on the mecharu 'sm of oxidation; one is that oxidation occuls a t the 3k/oxi.de interface (Akdezrazik, et al, 1987) and the other is that oxidation tdkes place a t the oXide/metal interface (Iiirdam and Smeltzer, 1980) In order to study W& is mmect for the Al-cantaining allays, axidation of the alloys were m o m , first in pure I6o2, and then follmed by pure 180~. secondary ion mass spectosco~ (SIMS) imaging results showed no layered structure but did shew a mixtUre of oxides. Thus, themecharusm ' of xidation of these alloys is not simple and must be cccurring in such a manner as to allow DISCLAIMERPortions of this document may be illegible in electronic image products. Images are produced from the best available original document. DISCLAIMERThis report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not nccessarily constitute or imply its endorsement, rcwmmendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.-1 1 -:,"LLLl.!.LIi prcducticn of a glass-ceramic to n e m seal in the mmfacture of pyratechru 'c actuators a ignitors ...
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