Stainless Steel Mesh Substrates Research Articles

Field emission characteristics of boron nitride nanofilms deposited on substrate with various work functions

Hexagonal polycrystalline boron nitride (BN) films are synthesized on Si and stainless steel mesh (SSM) substrates by plasma-assisted chemical vapor deposition. The BN film is as thin as 8–10 nm, being called nanofilm here. Field emission characteristics are measured for the substrates before and after deposition of the BN nanofilm. It is demonstrated for the BN nanofilm/flat Si substrate sample that the BN nanofilm reduces the effective potential barrier height through which electrons are tunneled, decreasing the turn-on electric field. In the case of the Ti-evaporated SSM substrate with a lower work function than that of Ni, the turn-on electric field is further reduced. The turn-on electric field as low as 3.0 V/μm is achieved for the BN nanofilm/Ti/SSM sample.

Structure and size distribution of TiO2 nanoparticles deposited on stainless steel mesh

Doped and undoped TiO2 nanoparticles with narrow size distribution were deposited on stainless steel mesh substrates by metalorganic chemical vapor deposition. The chemical composition of TiO2 nanoparticles was measured by energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. X-ray diffraction and transmission electron microscopy were performed to investigate the size and the size distribution of particles as well as the structural phase transitions. For pure TiO2, the results showed that anatase polycrystalline nanoparticles with average size from 23 to 31 nm were obtained for substrate temperatures between 350 and 600 °C. Particles deposited below 350 °C were x-ray amorphous and rutile began to precipitate at temperatures above 700 °C. The particles synthesized at 600 °C had the smallest size and narrowest size distribution. In order to study the dopant effects on the photocatalytic properties, growth temperature of 600 °C was selected to prepare 1 at. % Nd3+ doped TiO2 nanoparticles. The results of photodegradation of the pollutant 2-chlorophenol solution irradiated under ultraviolet light showed that 1 at. % of Nd3+ doped TiO2 had an enhanced degradation of the pollutant. The enhancement of photocatalytic efficiency by doped nanoparticles was ascribed to the large surface area and trapping induced prolonged lifetime of holes.

Characterization and cure of dielectric and conducting polymer thick films

Polymer thick films are screenable polymer pastes which vary from electrically non-conducting to electrically conducting. These materials typically contain significant amounts of high boiling solvents, and cure therefore involves removal of solvent in addition to crosslinking of the polymer matrix. In this study thermogravimetric analysis and dynamic mechanical analysis were utilized to characterize the residual solvent and glass transition behavior, respectively, with cure of the polymer thick films. Thickness was maintained constant at approximately 25μ and 100μ by using stainless steel mesh substrates. Results showed that IR curing, although able to heat more rapidly, did not accelerate the cure beyond that expected from time at temperature. Time-temperature superposition kinetics were employed to measure activation energy of cure, generate master cure curves, and to quantify IR cure time-temperature profiles. Cure models describing Tg and residual cure as a function of time, temperature, and film thickness were developed.