Tantalum Nitride Thin-Film Ratiometer for Electronic Timer of XM732 Proximity Fuze.
Abstract
This report covers the performance evaluation of commercially produced thin-film ratiometers developed for use in the electronic timer of the XM732 Proximity Fuze. The resistor network, consisting of a 432-kilohm linear variable resistor and a 3-kilohm fixed resistor, provides a means of setting a delay time of 2 to 144 s before fuze turn on. The ratiometer elements were fabricated from sputtered tantalum nitride (TaN) and vacuum-evaporated chromium/gold (Cr/Au) or Cr deposited on 99.5 percent alumina. The resistive and conductor/commutator areas were defined by photolithography and selectively etched in a batch process. The TaN films exhibited excellent properties, whereas the Au commutator pads tended to smear under the pressure of the traversing spring contact. Additional investigation found thick Cr films to have the desired wear characteristics. Improved process control successfully demonstrated conformity as to resistor-tolerance, linearity, mechanical, and environmental specifications. The ability to meet these specifications qualified the design and TaN/Cr materials combination for inclusion in the Specification Control Drawing for the Detonator Block Assembly. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1975
- Accession Number
- ADA020670
Entities
People
- Lauren H. Bullis
- Lester A. Kitchman
Organizations
- Harry Diamond Laboratories